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Internet Engineering Task Force (IETF)                        R. DanyliwRequest for Comments: 7970                                          CERTObsoletes:5070,6685                                      November 2016Category: Standards TrackISSN: 2070-1721The Incident Object Description Exchange Format Version 2Abstract   The Incident Object Description Exchange Format (IODEF) defines a   data representation for security incident reports and indicators   commonly exchanged by operational security teams for mitigation and   watch and warning.  This document describes an updated information   model for the IODEF and provides an associated data model specified   with the XML schema.  This new information and data model obsoletes   RFCs 5070 and 6685.Status of This Memo   This is an Internet Standards Track document.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Further information on   Internet Standards is available inSection 2 of RFC 7841.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc7970.Danyliw                      Standards Track                    [Page 1]

RFC 7970                     IODEF Version 2               November 2016Copyright Notice   Copyright (c) 2016 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 78 and the IETF Trust's Legal   Provisions Relating to IETF Documents   (http://trustee.ietf.org/license-info) in effect on the date of   publication of this document.  Please review these documents   carefully, as they describe your rights and restrictions with respect   to this document.  Code Components extracted from this document must   include Simplified BSD License text as described in Section 4.e of   the Trust Legal Provisions and are provided without warranty as   described in the Simplified BSD License.   This document may contain material from IETF Documents or IETF   Contributions published or made publicly available before November   10, 2008.  The person(s) controlling the copyright in some of this   material may not have granted the IETF Trust the right to allow   modifications of such material outside the IETF Standards Process.   Without obtaining an adequate license from the person(s) controlling   the copyright in such materials, this document may not be modified   outside the IETF Standards Process, and derivative works of it may   not be created outside the IETF Standards Process, except to format   it for publication as an RFC or to translate it into languages other   than English.Danyliw                      Standards Track                    [Page 2]

RFC 7970                     IODEF Version 2               November 2016Table of Contents1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .51.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .61.2.  Notations . . . . . . . . . . . . . . . . . . . . . . . .61.3.  About the IODEF Data Model  . . . . . . . . . . . . . . .71.4.  Changes fromRFC 5070 . . . . . . . . . . . . . . . . . .72.  IODEF Data Types  . . . . . . . . . . . . . . . . . . . . . .92.1.  Integers  . . . . . . . . . . . . . . . . . . . . . . . .92.2.  Real Numbers  . . . . . . . . . . . . . . . . . . . . . .92.3.  Characters and Strings  . . . . . . . . . . . . . . . . .92.4.  Multilingual Strings  . . . . . . . . . . . . . . . . . .92.5.  Binary Strings  . . . . . . . . . . . . . . . . . . . . .102.5.1.  Base64 Bytes  . . . . . . . . . . . . . . . . . . . .102.5.2.  Hexadecimal Bytes . . . . . . . . . . . . . . . . . .112.6.  Enumerated Types  . . . . . . . . . . . . . . . . . . . .112.7.  Date-Time String  . . . . . . . . . . . . . . . . . . . .112.8.  Timezone String . . . . . . . . . . . . . . . . . . . . .112.9.  Port Lists  . . . . . . . . . . . . . . . . . . . . . . .112.10. Postal Address  . . . . . . . . . . . . . . . . . . . . .122.11. Telephone Number  . . . . . . . . . . . . . . . . . . . .122.12. Email String  . . . . . . . . . . . . . . . . . . . . . .122.13. Uniform Resource Locator Strings  . . . . . . . . . . . .122.14. Identifiers and Identifier References . . . . . . . . . .122.15. Software  . . . . . . . . . . . . . . . . . . . . . . . .132.15.1.  SoftwareReference Class  . . . . . . . . . . . . . .142.16. Extension . . . . . . . . . . . . . . . . . . . . . . . .153.  The IODEF Information Model . . . . . . . . . . . . . . . . .183.1.  IODEF-Document Class  . . . . . . . . . . . . . . . . . .183.2.  Incident Class  . . . . . . . . . . . . . . . . . . . . .203.3.  Common Attributes . . . . . . . . . . . . . . . . . . . .233.3.1.  restriction Attribute . . . . . . . . . . . . . . . .233.3.2.  observable-id Attribute . . . . . . . . . . . . . . .253.4.  IncidentID Class  . . . . . . . . . . . . . . . . . . . .253.5.  AlternativeID Class . . . . . . . . . . . . . . . . . . .263.6.  RelatedActivity Class . . . . . . . . . . . . . . . . . .273.7.  ThreatActor Class . . . . . . . . . . . . . . . . . . . .283.8.  Campaign Class  . . . . . . . . . . . . . . . . . . . . .293.9.  Contact Class . . . . . . . . . . . . . . . . . . . . . .303.9.1.  RegistryHandle Class  . . . . . . . . . . . . . . . .343.9.2.  PostalAddress Class . . . . . . . . . . . . . . . . .353.9.3.  Email Class . . . . . . . . . . . . . . . . . . . . .363.9.4.  Telephone Class . . . . . . . . . . . . . . . . . . .373.10. Discovery Class . . . . . . . . . . . . . . . . . . . . .383.10.1.  DetectionPattern Class . . . . . . . . . . . . . . .403.11. Method Class  . . . . . . . . . . . . . . . . . . . . . .413.11.1.  Reference Class  . . . . . . . . . . . . . . . . . .42Danyliw                      Standards Track                    [Page 3]

RFC 7970                     IODEF Version 2               November 20163.12. Assessment Class  . . . . . . . . . . . . . . . . . . . .433.12.1.  SystemImpact Class . . . . . . . . . . . . . . . . .453.12.2.  BusinessImpact Class . . . . . . . . . . . . . . . .483.12.3.  TimeImpact Class . . . . . . . . . . . . . . . . . .503.12.4.  MonetaryImpact Class . . . . . . . . . . . . . . . .523.12.5.  Confidence Class . . . . . . . . . . . . . . . . . .533.13. History Class . . . . . . . . . . . . . . . . . . . . . .543.13.1.  HistoryItem Class  . . . . . . . . . . . . . . . . .543.14. EventData Class . . . . . . . . . . . . . . . . . . . . .573.14.1.  Relating the Incident and EventData Classes  . . . .593.14.2.  Recursive Definition of EventData  . . . . . . . . .593.15. Expectation Class . . . . . . . . . . . . . . . . . . . .603.16. Flow Class  . . . . . . . . . . . . . . . . . . . . . . .633.17. System Class  . . . . . . . . . . . . . . . . . . . . . .643.18. Node Class  . . . . . . . . . . . . . . . . . . . . . . .673.18.1.  Address Class  . . . . . . . . . . . . . . . . . . .683.18.2.  NodeRole Class . . . . . . . . . . . . . . . . . . .693.18.3.  Counter Class  . . . . . . . . . . . . . . . . . . .733.19. DomainData Class  . . . . . . . . . . . . . . . . . . . .753.19.1.  Nameservers Class  . . . . . . . . . . . . . . . . .773.19.2.  DomainContacts Class . . . . . . . . . . . . . . . .783.20. Service Class . . . . . . . . . . . . . . . . . . . . . .793.20.1.  ServiceName Class  . . . . . . . . . . . . . . . . .803.20.2.  ApplicationHeader Class  . . . . . . . . . . . . . .813.21. EmailData Class . . . . . . . . . . . . . . . . . . . . .823.22. Record Class  . . . . . . . . . . . . . . . . . . . . . .833.22.1.  RecordData Class . . . . . . . . . . . . . . . . . .843.22.2.  RecordPattern Class  . . . . . . . . . . . . . . . .853.23. WindowsRegistryKeysModified Class . . . . . . . . . . . .873.23.1.  Key Class  . . . . . . . . . . . . . . . . . . . . .883.24. CertificateData Class . . . . . . . . . . . . . . . . . .893.24.1.  Certificate Class  . . . . . . . . . . . . . . . . .903.25. FileData Class  . . . . . . . . . . . . . . . . . . . . .903.25.1.  File Class . . . . . . . . . . . . . . . . . . . . .913.26. HashData Class  . . . . . . . . . . . . . . . . . . . . .923.26.1.  Hash Class . . . . . . . . . . . . . . . . . . . . .943.26.2.  FuzzyHash Class  . . . . . . . . . . . . . . . . . .953.27. SignatureData Class . . . . . . . . . . . . . . . . . . .953.28. IndicatorData Class . . . . . . . . . . . . . . . . . . .963.29. Indicator Class . . . . . . . . . . . . . . . . . . . . .963.29.1.  IndicatorID Class  . . . . . . . . . . . . . . . . .993.29.2.  AlternativeIndicatorID Class . . . . . . . . . . . .1003.29.3.  Observable Class . . . . . . . . . . . . . . . . . .1013.29.4.  IndicatorExpression Class  . . . . . . . . . . . . .1063.29.5.  Expressions with IndicatorExpression . . . . . . . .1083.29.6.  ObservableReference Class  . . . . . . . . . . . . .1103.29.7.  IndicatorReference Class . . . . . . . . . . . . . .1103.29.8.  AttackPhase Class  . . . . . . . . . . . . . . . . .111Danyliw                      Standards Track                    [Page 4]

RFC 7970                     IODEF Version 2               November 20164.  Processing Considerations . . . . . . . . . . . . . . . . . .1124.1.  Encoding  . . . . . . . . . . . . . . . . . . . . . . . .1124.2.  IODEF Namespace . . . . . . . . . . . . . . . . . . . . .1124.3.  Validation  . . . . . . . . . . . . . . . . . . . . . . .1124.4.  Incompatibilities with v1 . . . . . . . . . . . . . . . .1135.  Extending the IODEF . . . . . . . . . . . . . . . . . . . . .1145.1.  Extending the Enumerated Values of Attributes . . . . . .1145.1.1.  Private Extension of Enumerated Values  . . . . . . .1145.1.2.  Public Extension of Enumerated Values . . . . . . . .1155.2.  Extending Classes . . . . . . . . . . . . . . . . . . . .1155.3.  Deconflicting Private Extensions  . . . . . . . . . . . .1176.  Internationalization Issues . . . . . . . . . . . . . . . . .1187.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .1197.1.  Minimal Example . . . . . . . . . . . . . . . . . . . . .1197.2.  Indicators from a Campaign  . . . . . . . . . . . . . . .1208.  The IODEF Data Model (XML Schema) . . . . . . . . . . . . . .1219.  Security Considerations . . . . . . . . . . . . . . . . . . .1619.1.  Security  . . . . . . . . . . . . . . . . . . . . . . . .1619.2.  Privacy . . . . . . . . . . . . . . . . . . . . . . . . .16210. IANA Considerations . . . . . . . . . . . . . . . . . . . . .16310.1.  Namespace and Schema . . . . . . . . . . . . . . . . . .16310.2.  Enumerated Value Registries  . . . . . . . . . . . . . .16310.3.  Expert Review of IODEF-Related XML Registry Entries  . .16611. References  . . . . . . . . . . . . . . . . . . . . . . . . .16711.1.  Normative References . . . . . . . . . . . . . . . . . .16711.2.  Informative References . . . . . . . . . . . . . . . . .170   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .171   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .1721.  Introduction   Organizations require help from other parties to mitigate malicious   activity targeting their network and to gain insight into potential   threats.  This coordination might entail working with an ISP to   filter attack traffic, contacting a remote site to take down a   botnet, or sharing watch lists of known malicious indicators in a   consortium.   The Incident Object Description Exchange Format (IODEF) is a format   for representing computer security information commonly exchanged   between Computer Security Incident Response Teams (CSIRTs) or other   operational security teams.  It provides an XML representation for   conveying:   o  indicators to characterize a threat;   o  security incident reports to document attacks against an      organization;Danyliw                      Standards Track                    [Page 5]

RFC 7970                     IODEF Version 2               November 2016   o  response activity taken or that could be taken in response to an      incident; and   o  metadata so that these various classes of information can be      exchanged among parties.   The purpose of the IODEF is to enhance the operational capabilities   of CSIRTs.  Adoption of the IODEF will improve the ability of a CSIRT   to resolve security incidents; understand threats; and coordinate   response activities and proactive mitigations by simplifying   collaboration and data sharing with its partners.  This structured   format provided by the IODEF allows for:   o  machine-to-machine exchange of incident and indicator data;   o  automated processing of this data whereby allowing more rapid      execution of appropriate courses of action; and   o  the development of an ecosystem of interoperable tools enabling      security operations.   Sharing and coordinating with other organizations is not strictly a   technical problem.  There are numerous procedural, cultural, legal,   and trust-related barriers to overcome.  The IODEF does not attempt   to address them directly.  However, operational implementations of   the IODEF will need to consider these challenges.Section 1 provides the background for the IODEF.  Sections3 and8   specify the IODEF information and data model, respectively.  The data   types used in this document are described inSection 2.  Processing   considerations, extending the specification, internationalization,   and security issues are covered in Sections4,5,6, and9,   respectively.  Examples are listed inSection 7.1.1.  Terminology   The key words "MUST," "MUST NOT," "REQUIRED," "SHALL," "SHALL NOT,"   "SHOULD," "SHOULD NOT," "RECOMMENDED," "MAY," and "OPTIONAL" in this   document are to be interpreted as described in [RFC2119].1.2.  Notations   The IODEF is specified as an Extensible Markup Language (XML)   [W3C.XML] schema [W3C.SCHEMA].  The normative IODEF data model is   found in the XML schema inSection 8.  To aid in the understanding of   the data elements,Section 3 also depicts the underlying information   model using Unified Modeling Language (UML).  This abstract   presentation of the IODEF is not normative.Danyliw                      Standards Track                    [Page 6]

RFC 7970                     IODEF Version 2               November 2016   For clarity in this document, the term "XML document" will be used   when referring generically to any instance of an XML document.  The   term "IODEF document" will be used to refer to an XML document   conforming to the IODEF specification.  The terms "schema" will be   used to refer toSection 8 of this document.  The terms "data model"   and "schema" will be used interchangeably.  The terms "class" and   "element" will be used to reference either the corresponding data   element in the UML-based information or XML schema-based data models,   respectively.1.3.  About the IODEF Data Model   A number of considerations were made in the design of the IODEF data   model.   o  The data model found in this document is an evolution of the one      previously specified in [RFC5070].  New fields were added to      represent additional information.  [RFC5070] was developed      primarily to represent incident reports.  This document builds      upon it by adding support for indicators and revising it to      reflect the current challenges faced by CSIRTs.  An attempt was      made to preserve backward compatibility, but this was not possible      in all cases.  SeeSection 4.4.  This document obsoletes      [RFC5070].   o  The IODEF is a transport format.  Therefore, the data model may      not be the optimal archival or in-memory processing format.   o  The IODEF is intended to be a framework to convey only commonly      exchanged information.  It ensures that there are mechanisms for      extensibility to support organization-specific information and      techniques to reference information kept outside of the data      model.   o  Not all commonly exchanged information has a well-defined format      or taxonomy.  The IODEF attempts to strike a balance between      enforcing sufficient structure to allow automated processing and      supporting free-form content that enables maximum flexibility.   o  The IODEF fits into a broader ecosystem of standards and      conventions.  An attempt was made to harmonize the data model with      this context.1.4.  Changes fromRFC 5070   A detailed list of additions made to the data model in [RFC5070] are   enumerated in this section.  SeeSection 4.4 for a list of   incompatible changes.Danyliw                      Standards Track                    [Page 7]

RFC 7970                     IODEF Version 2               November 2016   o  Updated the data types (Section 2) to improve      internationalization, clarify ambiguity, and ensure consistency in      extensions.   o  Added the observable-id attribute (Section 3.3.2) and      IndicatorData class (Section 3.28) to represent indicators.   o  Added the private-enum-name and private-enum-id attributes to the      IODEF-Document class (Section 3.1) to disambiguate private      extensions.   o  Updated the Incident class (Section 3.2) to represent additional      timing and workflow information.   o  Added the ThreatActor (Section 3.7) and Campaign (Section 3.8)      classes to represent attack attribution information.   o  Updated the Contact class (Section 3.9) and its children to      improve internationalization and represent additional information      about an entity.   o  Updated the Method class (Section 3.11) to improve extensibility      through externally referenced resources.   o  Added the Discovery class (Section 3.10) to describe how an      incident was discovered.   o  Updated the Assessment class (Section 3.12) to enable more      descriptive characterizations of the impact of an incident.   o  Updated the HistoryItem (Section 3.13.1) and Expectation      (Section 3.15) classes to support a reference to a course of      action.   o  Updated the EventData class (Section 3.14) with additional      metadata added to the Incident class.   o  Updated the System class (Section 3.17) with additional metadata.   o  Updated the Counter class (Section 3.18.3) to support additional      rate metrics.   o  Added DomainData (Section 3.19), EmailData (Section 3.21),      WindowsRegistryKeysModified (Section 3.23), CertificateData      (Section 3.24), and FileData (Section 3.25) classes to improve the      description of an incident and support this data as indicators.Danyliw                      Standards Track                    [Page 8]

RFC 7970                     IODEF Version 2               November 2016   o  Added the SignatureData (Section 3.27) and HashData (Section 3.26)      classes to represent digital signatures and hashes.   o  Added support for public enumerated attribute extensions using      IANA registries (Section 5.1.2).   o  Updated numerous enumerated attributes for completeness.2.  IODEF Data Types   The IODEF uses a number of simple and complex types.  This section   describes these data types.2.1.  Integers   An integer is represented in the information model by the INTEGER   data type.  Integer data MUST be encoded in Base 10.   The INTEGER data type is implemented in the data model as an   "xs:integer" type per Section 3.3.13 of [W3C.SCHEMA.DTYPES].2.2.  Real Numbers   A real (floating-point) number is represented in the information   model by the REAL data type.  Real data MUST be encoded in Base 10.   The REAL data type is implemented in the data model as an "xs:float"   type per Section 3.2.4 of [W3C.SCHEMA.DTYPES].2.3.  Characters and Strings   A single character is represented in the information model by the   CHARACTER data type.  A string is represented by the STRING data   type.  Special characters MUST be encoded using entity references.   SeeSection 4.1.   The CHARACTER and STRING data types are implemented in the data model   as an "xs:string" type per Section 3.2.1 of [W3C.SCHEMA.DTYPES].2.4.  Multilingual Strings   A string that needs to be represented in a human-readable language   different than the default encoding of the document is represented in   the information model by the ML_STRING data type.   The ML_STRING data type is implemented in the data model as the   "iodef:MLStringType" type.  This type extends the "xs:string" to   include two attributes.Danyliw                      Standards Track                    [Page 9]

RFC 7970                     IODEF Version 2               November 2016   +------------------------+   | iodef:MLStringType     |   +------------------------+   | xs:string              |   |                        |   | ENUM xml:lang          |   | STRING translation-id  |   +------------------------+                   Figure 1: The iodef:MLStringType Type   The content of the class is a character string of type "xs:string"   whose language MAY be specified by the xml:lang attribute.   The attributes of the iodef:MLStringType type are:   xml:lang      Optional.  ENUM.  A language identifier per Section 2.12 of      [W3C.XML] whose values and format are described in [RFC5646].  The      interpretation of this code is described inSection 6.   translation-id      Optional.  STRING.  An identifier to relate other instances of      this class with the same parent as translations of this text.  The      scope of this identifier is limited to all of the direct, peer      child classes of a given parent class.   Using this class enables representing translations of the same text   in multiple languages.  Each translation is a distinct instance of   this class with a common parent.  A group of classes each with a   translated instance of text is related by setting a common identifier   in the translation-id attribute.  The language of a given class is   set by the xml:lang attribute.  SeeSection 6 for more details on   representing translations of free-form text.2.5.  Binary Strings   Binary octets can be represented with two encodings.2.5.1.  Base64 Bytes   A binary octet encoded with base64 is represented in the information   model by the BYTE data type.  A sequence of these octets is of the   BYTE[] data type.   The BYTE and BYTE[] data types are implemented in the data model as   an "xs:base64Binary" type per Section 3.2.16 of [W3C.SCHEMA.DTYPES].Danyliw                      Standards Track                   [Page 10]

RFC 7970                     IODEF Version 2               November 20162.5.2.  Hexadecimal Bytes   A binary octet encoded as a character tuple consistent of two   hexadecimal digits is represented in the information model by the   HEXBIN data type.  A sequence of these octets is of the HEXBIN[] data   type.   The HEXBIN and HEXBIN[] data types are implemented in the data model   as an "xs:hexBinary" type per Section 3.2.15 of [W3C.SCHEMA.DTYPES].2.6.  Enumerated Types   An enumerated type is represented in the information model by the   ENUM data type.  It is an ordered list of acceptable string values.   Each value has a representative keyword.  Within the data model, the   enumerated type keywords are used as attribute values.   The ENUM data type is implemented in the data model as values of an   "xs:NMTOKEN" type per Section 3.3.4 of [W3C.SCHEMA.DTYPES].2.7.  Date-Time String   A date-time string that describes a particular instant in time is   represented in the information model by the DATETIME data type.   Ranges are not supported.   The DATETIME data type is implemented in the data model as an   "xs:dateTime" type per Section 3.2.7 of [W3C.SCHEMA.DTYPES].2.8.  Timezone String   A timezone offset from UTC is represented in the information model by   the TIMEZONE data type.  It is formatted according to the following   regular expression: "Z|[\+\-](0[0-9]|1[0-4]):[0-5][0-9]".   The TIMEZONE data type is implemented in the data model as an   "iodef:TimezoneType" type.2.9.  Port Lists   A list of network ports is represented in the information model by   the PORTLIST data type.  A PORTLIST consists of a comma-separated   list of numbers and ranges (N-M means ports N through M, inclusive).   It is formatted according to the following regular expression:   "\d+(\-\d+)?(,\d+(\-\d+)?)*".  For example,   "2,5-15,30,32,40-50,55-60".Danyliw                      Standards Track                   [Page 11]

RFC 7970                     IODEF Version 2               November 2016   The PORTLIST data type is implemented in the data model as an   "iodef:PortlistType" type.2.10.  Postal Address   A postal address is represented in the information model by the   POSTAL data type.  The format of the POSTAL data type is documented   inSection 2.23 of [RFC4519] as a free-form multi-line string   separated by the "$" character.   The POSTAL data type is implemented in the data model as an   "iodef:MLStringType" type.2.11.  Telephone Number   A telephone number is represented in the information model by the   PHONE data type.  The format of the PHONE data type is documented in   [E.164].   The PHONE data type is implemented in the data model as an   "xs:string" type per Section 3.2.1 of [W3C.SCHEMA.DTYPES].2.12.  Email String   An email address is represented in the information model by the EMAIL   data type.  The format of the EMAIL data type is documented inSection 3.4.1 of [RFC5322] andSection 3.3 of [RFC6531].   The EMAIL data type is implemented in the data model as an   "xs:string" type per Section 3.2.1 of [W3C.SCHEMA.DTYPES].2.13.  Uniform Resource Locator Strings   A uniform resource locator (URL) is represented in the information   model by the URL data type.  The format of the URL data type is   documented in [RFC3986].   The URL data type is implemented as an "xs:anyURI" type per   Section 3.2.17 of [W3C.SCHEMA.DTYPES].2.14.  Identifiers and Identifier References   An identifier unique to the IODEF document is represented in the   information model by the ID data type.  A reference to this   identifier is represented by the IDREF data type.Danyliw                      Standards Track                   [Page 12]

RFC 7970                     IODEF Version 2               November 2016   The ID and IDREF data types are implemented in the model as "xs:ID"   and "xs:IDREF" types per Sections3.3.8 and3.3.9 of   [W3C.SCHEMA.DTYPES].2.15.  Software   A particular version of software is represented in the information   model by the SOFTWARE data type.  This software can be described by   using a reference, a URL, or with free-form text.   The SOFTWARE data type is implemented in the data model as the   "iodef:SoftwareType" type.   +--------------------+   | iodef:SoftwareType |   +--------------------+   |                    |<>--{0..1}--[ SoftwareReference ]   |                    |<>--{0..*}--[ URL               ]   |                    |<>--{0..*}--[ Description       ]   +--------------------+                      Figure 2: The SoftwareType Type   The aggregate classes of the SoftwareType type are:   SoftwareReference      Zero or one.  Reference to a software application.  SeeSection 2.15.1.   URL      Zero or more.  URL.  A URL to a resource describing the software.   Description      Zero or more.  ML_STRING.  A free-form text description of the      software.   At least one of these classes MUST be present.   The iodef:SoftwareType type has no attributes.Danyliw                      Standards Track                   [Page 13]

RFC 7970                     IODEF Version 2               November 20162.15.1.  SoftwareReference Class   The SoftwareReference class is a reference to a particular version of   software.   +----------------------+   | SoftwareReference    |   +----------------------+   | xs:any               |   |                      |   | ENUM spec-name       |   | STRING ext-spec-name |   | ENUM dtype           |   | STRING ext-dtype     |   +----------------------+                   Figure 3: The SoftwareReference Class   The element content varies according to the value of the spec-name   attribute.  It is defined in the data model as "xs:any" per   [W3C.SCHEMA].   The attributes of the SoftwareReference class are:   spec-name      Required.  ENUM.  Identifies the format and semantics of the      element body of this class.  Formal standards and specifications      can be referenced as well as a free-form text description with a      user-provided data type.  These values are maintained in the      "SoftwareReference-spec-id" IANA registry perSection 10.2      1.  custom.  The element content is free-form and of the data type          specified by the dtype attribute.  If this value is selected,          then the dtype attribute MUST be set.      2.  cpe.  The element content describes a Common Platform          Enumeration (CPE) entry per [NIST.CPE].      3.  swid.  The element content describes a software identification          (SWID) tag per [ISO19770].      4.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 14]

RFC 7970                     IODEF Version 2               November 2016   ext-spec-name      Optional.  STRING.  A means by which to extend the spec-name      attribute.  SeeSection 5.1.1.   dtype      Optional.  ENUM.  The data type of the element content.  The      permitted values for this attribute are shown below.  The default      value is "string".  These values are maintained in the      "SoftwareReference-dtype" IANA registry perSection 10.2.      1.  bytes.  The element content is of type HEXBIN.      2.  integer.  The element content is of type INTEGER.      3.  real.  The element content is of type REAL.      4.  string.  The element content is of type STRING.      5.  xml.  The element content is XML.  SeeSection 5.2.      6.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-dtype      Optional.  STRING.  A means by which to extend the dtype      attribute.  SeeSection 5.1.1.2.16.  Extension   Information not otherwise represented in the IODEF can be added using   the EXTENSION data type.  This data type is a generic extension   mechanism.   The EXTENSION data type is implemented in the data model as the   "iodef:ExtensionType" type.   The data type of an EXTENSION is described by the dtype attribute.   For simple information, atomic data types (e.g., integers, strings)   are supported.  Their semantics are further described by the meaning   and formatid attributes.  Encapsulating XML documents conforming to   another schema is also supported.  A detailed discussion of extending   the schema can be found inSection 5.  Additional coordination may be   required to ensure that a recipient of a document using this type can   parse and process it.Danyliw                      Standards Track                   [Page 15]

RFC 7970                     IODEF Version 2               November 2016   +------------------------+   | iodef:ExtensionType    |   +------------------------+   | xs:any                 |   |                        |   | STRING name            |   | ENUM dtype             |   | STRING ext-dtype       |   | STRING meaning         |   | STRING formatid        |   | ENUM restriction       |   | STRING ext-restriction |   | ID observable-id       |   +------------------------+                  Figure 4: The iodef:ExtensionType Type   The element content of this type is the extension being added to the   data model.  This content is defined in the data model as "xs:any"   per [W3C.SCHEMA].   The attributes of the iodef:ExtensionType type are:   name      Optional.  STRING.  A free-form name of the field or data element.   dtype      Required.  ENUM.  The data type of the element content.  The      default value is "string".  These values are maintained in the      "ExtensionType-dtype" IANA registry perSection 10.2.      1.   boolean.  The element content is of type BOOLEAN.      2.   byte.  The element content is of type BYTE.      3.   bytes.  The element content is of type HEXBIN.      4.   character.  The element content is of type CHARACTER.      5.   date-time.  The element content is of type DATETIME.      6.   ntpstamp.  Same as date-time.      7.   integer.  The element content is of type INTEGER.      8.   portlist.  The element content is of type PORTLIST.      9.   real.  The element content is of type REAL.Danyliw                      Standards Track                   [Page 16]

RFC 7970                     IODEF Version 2               November 2016      10.  string.  The element content is of type STRING.      11.  file.  The element content is a base64-encoded binary file           encoded as a BYTE[] type.      12.  path.  The element content is a file-system path encoded as a           STRING type.      13.  frame.  The element content is a Layer 2 frame encoded as a           HEXBIN type.      14.  packet.  The element content is a Layer 3 packet encoded as a           HEXBIN type.      15.  ipv4-packet.  The element content is an IPv4 packet encoded           as a HEXBIN type.      16.  ipv6-packet.  The element content is an IPv6 packet encoded           as a HEXBIN type.      17.  url.  The element content is of type URL.      18.  csv.  The element content is a comma-separated value (CSV)           list perSection 2 of [RFC4180] encoded as a STRING type.      19.  winreg.  The element content is a Microsoft Windows registry           key encoded as a STRING type.      20.  xml.  The element content is XML.  SeeSection 5.2.      21.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-dtype      Optional.  STRING.  A means by which to extend the dtype      attribute.  SeeSection 5.1.1.   meaning      Optional.  STRING.  A free-form text description of the element      content.   formatid      Optional.  STRING.  An identifier referencing the format or      semantics of the element content.Danyliw                      Standards Track                   [Page 17]

RFC 7970                     IODEF Version 2               November 2016   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.  The IODEF Information Model   The specifics of the IODEF information model are discussed in this   section.  Each class and its relationships with the other classes is   described.  When necessary, clarifications are made about translating   this information model to the schema inSection 8.3.1.  IODEF-Document Class   The IODEF-Document class is the top level class in the IODEF data   model.  All IODEF documents are an instance of this class.   +--------------------------+   | IODEF-Document           |   +--------------------------+   | STRING version           |<>--{1..*}--[ Incident       ]   | ENUM xml:lang            |<>--{0..*}--[ AdditionalData ]   | STRING format-id         |   | STRING private-enum-name |   | STRING private-enum-id   |   +--------------------------+                    Figure 5: The IODEF-Document Class   The aggregate classes of the IODEF-Document class are:   Incident      One or more.  The information related to a single incident.  SeeSection 3.2.   AdditionalData      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model.Danyliw                      Standards Track                   [Page 18]

RFC 7970                     IODEF Version 2               November 2016   The attributes of the IODEF-Document class are:   version      Required.  STRING.  The IODEF specification version number to      which this IODEF document conforms.  The value of this attribute      MUST be "2.00".   xml:lang      Optional.  ENUM.  A language identifier per Section 2.12 of      [W3C.XML] whose values and form are described in [RFC5646].  The      interpretation of this code is described inSection 6.   format-id      Optional.  STRING.  A free-form string to convey processing      instructions to the recipient of the document.  Its semantics must      be negotiated out of band.   private-enum-name      Optional.  STRING.  A globally unique identifier for the CSIRT      generating the document to deconflict private extensions used in      the document.  The fully qualified domain name (FQDN) associated      with the CSIRT MUST be used as the identifier.  SeeSection 5.3.   private-enum-id      Optional.  STRING.  An organizationally unique identifier for an      extension used in the document.  If this attribute is set, the      private-enum-name MUST also be set.  SeeSection 5.3.Danyliw                      Standards Track                   [Page 19]

RFC 7970                     IODEF Version 2               November 20163.2.  Incident Class   The Incident class describes commonly exchanged information when   reporting or sharing derived analysis from security incidents.   +-------------------------+   | Incident                |   +-------------------------+   | ENUM purpose            |<>----------[ IncidentID      ]   | STRING ext-purpose      |<>--{0..1}--[ AlternativeID   ]   | ENUM status             |<>--{0..*}--[ RelatedActivity ]   | STRING ext-status       |<>--{0..1}--[ DetectTime      ]   | ENUM xml:lang           |<>--{0..1}--[ StartTime       ]   | ENUM restriction        |<>--{0..1}--[ EndTime         ]   | STRING ext-restriction  |<>--{0..1}--{ RecoveryTime    ]   | ID observable-id        |<>--{0..1}--[ ReportTime      ]   |                         |<>----------[ GenerationTime  ]   |                         |<>--{0..*}--[ Description     ]   |                         |<>--{0..*}  [ Discovery       ]   |                         |<>--{0..*}--[ Assessment      ]   |                         |<>--{0..*}--[ Method          ]   |                         |<>--{1..*}--[ Contact         ]   |                         |<>--{0..*}--[ EventData       ]   |                         |<>--{0..1}--[ IndicatorData   ]   |                         |<>--{0..1}--[ History         ]   |                         |<>--{0..*}--[ AdditionalData  ]   +-------------------------+                       Figure 6: The Incident Class   The aggregate classes of the Incident class are:   IncidentID      One.  An incident tracking number assigned to this incident by the      CSIRT that generated the IODEF document.  SeeSection 3.4.   AlternativeID      Zero or one.  The incident tracking numbers used by other CSIRTs      to refer to the incident described in the document.  SeeSection 3.5.   RelatedActivity      Zero or more.  Related activity and attribution of this activity.      SeeSection 3.6.   DetectTime      Zero or one.  DATETIME.  The time the incident was first detected.Danyliw                      Standards Track                   [Page 20]

RFC 7970                     IODEF Version 2               November 2016   StartTime      Zero or one.  DATETIME.  The time the incident started.   EndTime      Zero or one.  DATETIME.  The time the incident ended.   RecoveryTime      Zero or one.  DATETIME.  The time the site recovered from the      incident.   ReportTime      Zero or one.  DATETIME.  The time the incident was reported.   GenerationTime      One.  DATETIME.  The time the content in this Incident class was      generated.   Description      Zero or more.  ML_STRING.  A free-form text description of the      incident.   Discovery      Zero or more.  The means by which this incident was detected.  SeeSection 3.10.   Assessment      Zero or more.  A characterization of the impact of the incident.      SeeSection 3.12.   Method      Zero or more.  The techniques used by the threat actor in the      incident.  SeeSection 3.11.   Contact      One or more.  Contact information for the parties involved in the      incident.  SeeSection 3.9.   EventData      Zero or more.  Description of the events comprising the incident.      SeeSection 3.14.   IndicatorData      Zero or one.  Indicators from the analysis of an incident.  SeeSection 3.28.   History      Zero or one.  A log of significant events or actions that occurred      during the course of handling the incident.  SeeSection 3.13.Danyliw                      Standards Track                   [Page 21]

RFC 7970                     IODEF Version 2               November 2016   AdditionalData      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model.   The attributes of the Incident class are:   purpose      Required.  ENUM.  The purpose attribute describes the rationale      for documenting the information in this class.  It is closely      related to the Expectation class (Section 3.15).  These values are      maintained in the "Incident-purpose" IANA registry perSection 10.2.  This attribute is defined as an enumerated list:      1.  traceback.  The incident was sent for trace-back purposes.      2.  mitigation.  The incident was sent to request aid in          mitigating the described activity.      3.  reporting.  The incident was sent to comply with reporting          requirements.      4.  watch.  The incident was sent to convey indicators that should          be monitored.      5.  other.  The incident was sent for purposes specified in the          Expectation class.      6.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-purpose      Optional.  STRING.  A means by which to extend the purpose      attribute.  SeeSection 5.1.1.   status      Optional.  ENUM.  The status attribute conveys the state in a      workflow where the incident is currently found.  These values are      maintained in the "Incident-status" IANA registry perSection 10.2.  This attribute is defined as an enumerated list:      1.  new.  The incident is newly reported, and no action has been          taken.      2.  in-progress.  The incident is under investigation.      3.  forwarded.  The incident has been forwarded to another party          for handling.Danyliw                      Standards Track                   [Page 22]

RFC 7970                     IODEF Version 2               November 2016      4.  resolved.  The investigation into the activity in this          incident has concluded.      5.  future.  The described activity has not yet been detected.      6.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-status      Optional.  STRING.  A means by which to extend the status      attribute.  SeeSection 5.1.1.   xml:lang      Optional.  ENUM.  A language identifier per Section 2.12 of      [W3C.XML] whose values and form are described in [RFC5646].  The      interpretation of this code is described inSection 6.   restriction      Optional.  ENUM.  SeeSection 3.3.1.  The default value is      "private".   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.3.  Common Attributes   There are a number of recurring attributes used in the information   model.  They are documented in this section.3.3.1.  restriction Attribute   The restriction attribute indicates the disclosure guidelines to   which the sender expects the recipient to adhere for the information   represented in this class and its children.  This guideline provides   no security since there are no technical means to ensure that the   recipient of the document handles the information as the sender   requested.   The value of this attribute is logically inherited by the children of   this class.  That is to say, the disclosure rules applied to this   class also apply to its children.Danyliw                      Standards Track                   [Page 23]

RFC 7970                     IODEF Version 2               November 2016   It is possible to set a granular disclosure policy, since all of the   high-level classes (i.e., children of the Incident class) have a   restriction attribute.  Therefore, a child can override the   guidelines of a parent class, be it to restrict or relax the   disclosure rules (e.g., a child has a weaker policy than an ancestor;   or an ancestor has a weak policy, and the children selectively apply   more rigid controls).  The implicit value of the restriction   attribute for a class that did not specify one can be found in the   closest ancestor that did specify a value.   This attribute is defined as an enumerated value with a default value   of "private".  Note that the default value of the restriction   attribute is only defined in the context of the Incident class.  In   other classes where this attribute is used, no default is specified.   These values are maintained in the "Restriction" IANA registry perSection 10.2.   1.   public.  The information can be freely distributed without        restriction.   2.   partner.  The information may be shared within a closed        community of peers, partners, or affected parties, but cannot be        openly published.   3.   need-to-know.  The information may be shared only within the        organization with individuals that have a need to know.   4.   private.  The information may not be shared.   5.   default.  The information can be shared according to an        information disclosure policy pre-arranged by the communicating        parties.   6.   white.  Same as 'public'.   7.   green.  Same as 'partner'.   8.   amber.  Same as 'need-to-know'.   9.   red.  Same as 'private'.   10.  ext-value.  A value used to indicate that this attribute is        extended and the actual value is provided using the        corresponding ext-* attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 24]

RFC 7970                     IODEF Version 2               November 20163.3.2.  observable-id Attribute   The observable-id attribute tags information in the document as an   observable so that it can be referenced later in the description of   an indicator.  The value of this attribute is a unique identifier in   the scope of the document.  It is used by the ObservableReference   class to enumerate observables when defining an indicator with the   IndicatorData class.3.4.  IncidentID Class   The IncidentID class represents a tracking number that is unique in   the context of the CSIRT.  It serves as an identifier for an incident   or a document identifier when sharing indicators.  This identifier   would serve as an index into a CSIRT's incident handling or knowledge   management system.   The combination of the name attribute and the string in the element   content MUST be a globally unique identifier describing the activity.   Documents generated by a given CSIRT MUST NOT reuse the same value   unless they are referencing the same incident.   +------------------------+   | IncidentID             |   +------------------------+   | STRING                 |   |                        |   | STRING name            |   | STRING instance        |   | ENUM restriction       |   | STRING ext-restriction |   +------------------------+                      Figure 7: The IncidentID Class   The content of the class is an incident identifier of type STRING.   The attributes of the IncidentID class are:   name      Required.  STRING.  An identifier describing the CSIRT that      created the document.  In order to have a globally unique CSIRT      name, the fully qualified domain name associated with the CSIRT      MUST be used.Danyliw                      Standards Track                   [Page 25]

RFC 7970                     IODEF Version 2               November 2016   instance      Optional.  STRING.  An identifier referencing a subset of the      named incident.   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.5.  AlternativeID Class   The AlternativeID class lists the tracking numbers used by CSIRTs,   other than the one generating the document, to refer to the identical   activity described in the IODEF document.  A tracking number listed   as an AlternativeID references the same incident detected by another   CSIRT.  The tracking numbers of the CSIRT that generated the IODEF   document must never be considered an AlternativeID.   +------------------------+   | AlternativeID          |   +------------------------+   | ENUM restriction       |<>--{1..*}--[ IncidentID ]   | STRING ext-restriction |   +------------------------+                     Figure 8: The AlternativeID Class   The aggregate class of the AlternativeID class is:   IncidentID      One or more.  The tracking number of another CSIRT.  SeeSection 3.4.   The attributes of the AlternativeID class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 26]

RFC 7970                     IODEF Version 2               November 20163.6.  RelatedActivity Class   The RelatedActivity class relates the information described in the   rest of the document to previously observed incidents or activity and   allows attribution to a specific actor or campaign.   +------------------------+   | RelatedActivity        |   +------------------------+   | ENUM restriction       |<>--{0..*}--[ IncidentID     ]   | STRING ext-restriction |<>--{0..*}--[ URL            ]   |                        |<>--{0..*}--[ ThreatActor    ]   |                        |<>--{0..*}--[ Campaign       ]   |                        |<>--{0..*}--[ IndicatorID    ]   |                        |<>--{0..1}--[ Confidence     ]   |                        |<>--{0..*}--[ Description    ]   |                        |<>--{0..*}--[ AdditionalData ]   +------------------------+                    Figure 9: The RelatedActivity Class   The aggregate classes of the RelatedActivity class are:   IncidentID      Zero or more.  The tracking number of a related incident.  SeeSection 3.4.   URL      Zero or more.  URL.  A URL to activity related to this incident.   ThreatActor      Zero or more.  The threat actor to whom the incident activity is      attributed.  SeeSection 3.7.   Campaign      Zero or more.  The campaign of a given threat actor to whom the      described activity is attributed.  SeeSection 3.8.   IndicatorID      Zero or more.  A reference to a related indicator.  SeeSection 3.4.   Confidence      Zero or one.  An estimate of the confidence in attributing this      RelatedActivity to the events described in the document.  SeeSection 3.12.5.Danyliw                      Standards Track                   [Page 27]

RFC 7970                     IODEF Version 2               November 2016   Description      Zero or more.  ML_STRING.  A description of how these      relationships were derived.   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.   The RelatedActivity class MUST have at least one instance of any of   the following child classes: IncidentID, URL, ThreatActor, Campaign,   Description, or AdditionalData.   The attributes of the RelatedActivity class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.7.  ThreatActor Class   The ThreatActor class describes a threat actor.   +------------------------+   | ThreatActor            |   +------------------------+   | ENUM restriction       |<>--{0..*}--[ ThreatActorID  ]   | STRING ext-restriction |<>--{0..*}--[ URL            ]   |                        |<>--{0..*}--[ Description    ]   |                        |<>--{0..*}--[ AdditionalData ]   +------------------------+                     Figure 10: The ThreatActor Class   The aggregate classes of the ThreatActor class are:   ThreatActorID      Zero or more.  STRING.  An identifier for the threat actor.   URL      Zero or more.  URL.  A URL to a reference describing the threat      actor.   Description      Zero or more.  ML_STRING.  A description of the threat actor.Danyliw                      Standards Track                   [Page 28]

RFC 7970                     IODEF Version 2               November 2016   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.   The ThreatActor class MUST have at least one instance of a child   class.   The attributes of the ThreatActor class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.8.  Campaign Class   The Campaign class describes a campaign of attacks by a threat actor.   +------------------------+   | Campaign               |   +------------------------+   | ENUM restriction       |<>--{0..*}--[ CampaignID     ]   | STRING ext-restriction |<>--{0..*}--[ URL            ]   |                        |<>--{0..*}--[ Description    ]   |                        |<>--{0..*}--[ AdditionalData ]   +------------------------+                       Figure 11: The Campaign Class   The aggregate classes of the Campaign class are:   CampaignID      Zero or more.  STRING.  An identifier for the campaign.   URL      Zero or more.  URL.  A URL to a reference describing the campaign.   Description      Zero or more.  ML_STRING.  A description of the campaign.   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.   The Campaign class MUST have at least one instance of a child class.Danyliw                      Standards Track                   [Page 29]

RFC 7970                     IODEF Version 2               November 2016   The attributes of the Campaign class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.9.  Contact Class   The Contact class describes contact information for organizations and   personnel involved in the incident.  This class allows for the naming   of the involved party, specifying contact information for them, and   identifying their role in the incident.   People and organizations are treated interchangeably as contacts; one   can be associated with the other using the recursive definition of   the class (the Contact class is aggregated into the Contact class).   The type attribute disambiguates the type of contact information   being provided.   The recursive definition of Contact provides a way to relate   information without requiring the explicit use of identifiers or   duplication of data.  A complete point of contact is derived by a   particular traversal from the root Contact class to the leaf Contact   class.  Each child Contact class logically inherits contact   information from its ancestors.   +------------------------+   | Contact                |   +------------------------+   | ENUM role              |<>--{0..*}--[ ContactName    ]   | STRING ext-role        |<>--{0..*}--[ ContactTitle   ]   | ENUM type              |<>--{0..*}--[ Description    ]   | STRING ext-type        |<>--{0..*}--[ RegistryHandle ]   | ENUM restriction       |<>--{0..*}--[ PostalAddress  ]   | STRING ext-restriction |<>--{0..*}--[ Email          ]   |                        |<>--{0..*}--[ Telephone      ]   |                        |<>--{0..1}--[ Timezone       ]   |                        |<>--{0..*}--[ Contact        ]   |                        |<>--{0..*}--[ AdditionalData ]   +------------------------+                       Figure 12: The Contact ClassDanyliw                      Standards Track                   [Page 30]

RFC 7970                     IODEF Version 2               November 2016   The aggregate classes of the Contact class are:   ContactName      Zero or more.  ML_STRING.  The name of the contact.  The contact      may either be an organization or a person.  The type attribute      disambiguates the semantics.   ContactTitle      Zero or more.  ML_STRING.  The title for the individual named in      the ContactName.   Description      Zero or more.  ML_STRING.  A free-form text description of the      contact.   RegistryHandle      Zero or more.  A handle name into the registry of the contact.      SeeSection 3.9.1.   PostalAddress      Zero or more.  The postal address of the contact.  SeeSection 3.9.2.   Email      Zero or more.  The email address of the contact.  SeeSection 3.9.3.   Telephone      Zero or more.  The telephone number of the contact.  SeeSection 3.9.4.   Timezone      Zero or one.  TIMEZONE.  The timezone in which the contact      resides.   Contact      Zero or more.  A recursive definition of the Contact class.  This      definition can be used to group common data pertaining to multiple      points of contact and is especially useful when listing multiple      contacts at the same organization.   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.   At least one of the aggregate classes MUST be present in an instance   of the Contact class.Danyliw                      Standards Track                   [Page 31]

RFC 7970                     IODEF Version 2               November 2016   The attributes of the Contact class are:   role      Required.  ENUM.  Indicates the role the contact fulfills.  These      values are maintained in the "Contact-role" IANA registry perSection 10.2.      1.   creator.  The entity that generates the document.      2.   reporter.  The entity that reported the information.      3.   admin.  An administrative contact or business owner for an           asset or organization.      4.   tech.  An entity responsible for the day-to-day management of           technical issues for an asset or organization.      5.   provider.  An external hosting provider for an asset.      6.   user.  An end-user of an asset or part of an organization.      7.   billing.  An entity responsible for billing issues for an           asset or organization.      8.   legal.  An entity responsible for legal issues related to an           asset or organization.      9.   irt.  An entity responsible for handling security issues for           an asset or organization.      10.  abuse.  An entity responsible for handling abuse originating           from an asset or organization.      11.  cc.  An entity that is to be kept informed about the events           related to an asset or organization.      12.  cc-irt.  A CSIRT or information-sharing organization           coordinating activity related to an asset or organization.      13.  leo.  A law enforcement organization supporting the           investigation of activity affecting an asset or organization.      14.  vendor.  The vendor that produces an asset.      15.  vendor-support.  A vendor that provides services.      16.  victim.  A victim in the incident.Danyliw                      Standards Track                   [Page 32]

RFC 7970                     IODEF Version 2               November 2016      17.  victim-notified.  A victim in the incident who has been           notified.      18.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-role      Optional.  STRING.  A means by which to extend the role attribute.      SeeSection 5.1.1.   type      Required.  ENUM.  Indicates the type of contact being described.      This attribute is defined as an enumerated list.  These values are      maintained in the "Contact-type" IANA registry perSection 10.2.      1.  person.  The information for this contact references an          individual.      2.  organization.  The information for this contact references an          organization.      3.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 33]

RFC 7970                     IODEF Version 2               November 20163.9.1.  RegistryHandle Class   The RegistryHandle class represents a handle into an Internet   registry or community-specific database.   +---------------------+   | RegistryHandle      |   +---------------------+   | STRING              |   |                     |   | ENUM registry       |   | STRING ext-registry |   +---------------------+                    Figure 13: The RegistryHandle Class   The content of the class is a handle into a registry of type STRING.   The attributes of the RegistryHandle class are:   registry      Required.  ENUM.  The database to which the handle belongs.  These      values are maintained in the "RegistryHandle-registry" IANA      registry perSection 10.2.  The possible values are:      1.  internic.  Internet Network Information Center      2.  apnic.  Asia Pacific Network Information Center      3.  arin.  American Registry for Internet Numbers      4.  lacnic.  Latin American and Caribbean Internet Addresses          Registry      5.  ripe.  Reseaux IP Europeens      6.  afrinic.  African Network Information Center      7.  local.  A database local to the CSIRT      8.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-registry      Optional.  STRING.  A means by which to extend the registry      attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 34]

RFC 7970                     IODEF Version 2               November 20163.9.2.  PostalAddress Class   The PostalAddress class specifies a postal address and associated   annotation.   +--------------------+   | PostalAddress      |   +--------------------+   | ENUM type          |<>----------[ PAddress         ]   | STRING ext-type    |<>--{0..*}--[ Description      ]   +--------------------+                    Figure 14: The PostalAddress Class   The aggregate classes of the PostalAddress class are:   PAddress      One.  POSTAL.  A postal address.   Description      Zero or more.  ML_STRING.  A free-form text description of the      address.   The attributes of the PostalAddress class are:   type      Optional.  ENUM.  Categorizes the type of address described in the      PAddress class.  These values are maintained in the      "PostalAddress-type" IANA registry perSection 10.2.      1.  street.  An address describing a physical location.      2.  mailing.  An address to which correspondence should be sent.      3.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 35]

RFC 7970                     IODEF Version 2               November 20163.9.3.  Email Class   The Email class specifies an email address and associated annotation.   +--------------------+   | Email              |   +--------------------+   | ENUM type          |<>----------[ EmailTo          ]   | STRING ext-type    |<>--{0..*}--[ Description      ]   +--------------------+                        Figure 15: The Email Class   The aggregate classes of the Email class are:   EmailTo      One.  EMAIL.  An email address.   Description      Zero or more.  ML_STRING.  A free-form text description of the      email address.   The attributes of the Email class are:   type      Optional.  ENUM.  Categorizes the type of email address described      in the EmailTo class.  These values are maintained in the "Email-      type" IANA registry perSection 10.2.      1.  direct.  An email address of an individual.      2.  hotline.  An email address regularly monitored for operational          purposes.      3.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 36]

RFC 7970                     IODEF Version 2               November 20163.9.4.  Telephone Class   The Telephone class describes a telephone number and associated   annotation.   +--------------------+   | Telephone          |   +--------------------+   | ENUM type          |<>----------[ TelephoneNumber  ]   | STRING ext-type    |<>--{0..*}--[ Description      ]   +--------------------+                      Figure 16: The Telephone Class   The aggregate classes of the Telephone class are:   TelephoneNumber      One.  PHONE.  A telephone number.   Description      Zero or more.  ML_STRING.  A free-form text description of the      phone number.   The attributes of the Telephone class are:   type      Optional.  ENUM.  Categorizes the type of telephone number      described in the TelephoneNumber class.  These values are      maintained in the "Telephone-type" IANA registry perSection 10.2.      1.  wired.  A number of a wire-line (land-line) phone.      2.  mobile.  A number of a mobile phone.      3.  fax.  A number to a fax machine.      4.  hotline.  A number to a regularly monitored operational          hotline.      5.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 37]

RFC 7970                     IODEF Version 2               November 20163.10.  Discovery Class   The Discovery class describes how an incident was detected.   +------------------------+   | Discovery              |   +------------------------+   | ENUM source            |<>--{0..*}--[ Description      ]   | STRING ext-source      |<>--{0..*}--[ Contact          ]   | ENUM restriction       |<>--{0..*}--[ DetectionPattern ]   | STRING ext-restriction |   +------------------------+                      Figure 17: The Discovery Class   The aggregate classes of the Discovery class are:   Description      Zero or more.  ML_STRING.  A free-form text description of how      this incident was detected.   Contact      Zero or more.  Contact information for the party that discovered      the incident.  SeeSection 3.9.   DetectionPattern      Zero or more.  Describes an application-specific configuration      that detected the incident.  SeeSection 3.10.1.   The attributes of the Discovery class are:   source      Optional.  ENUM.  Categorizes the techniques used to discover the      incident.  These values are partially derived from Table 3-1 of      [NIST800.61rev2].  These values are maintained in the "Discovery-      source" IANA registry perSection 10.2.      1.   nidps.  Network Intrusion Detection or Prevention System.      2.   hips.  Host-based Intrusion Prevention System.      3.   siem.  Security Information and Event Management System.      4.   av.  Antivirus or antispam software.      5.   third-party-monitoring.  Contracted third-party monitoring           service.Danyliw                      Standards Track                   [Page 38]

RFC 7970                     IODEF Version 2               November 2016      6.   incident.  The activity was discovered while investigating an           unrelated incident.      7.   os-log.  Operating system logs.      8.   application-log.  Application logs.      9.   device-log.  Network device logs.      10.  network-flow.  Network flow analysis.      11.  passive-dns.  Passive DNS analysis.      12.  investigation.  Manual investigation initiated based on           notification of a new vulnerability or exploit.      13.  audit.  Security audit.      14.  internal-notification.  A party within the organization           reported the activity.      15.  external-notification.  A party outside of the organization           reported the activity.      16.  leo.  A law enforcement organization notified the victim           organization.      17.  partner.  A customer or business partner reported the           activity to the victim organization.      18.  actor.  The threat actor directly or indirectly reported this           activity to the victim organization.      19.  unknown.  Unknown detection approach.      20.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-source      Optional.  STRING.  A means by which to extend the source      attribute.  SeeSection 5.1.1.   restriction      Optional.  ENUM.  SeeSection 3.3.1.Danyliw                      Standards Track                   [Page 39]

RFC 7970                     IODEF Version 2               November 2016   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.10.1.  DetectionPattern Class   The DetectionPattern class describes a configuration or signature   that can be used by an Intrusion Detection System (IDS) / Intrusion   Prevention System (IPS), SIEM, antivirus, endpoint protection,   network analysis, malware analysis, or host forensics tool to   identify a particular phenomenon.  This class requires the   identification of the target application and allows the configuration   to be described in either free form or machine-readable form.   +------------------------+   | DetectionPattern       |   +------------------------+   | ENUM restriction       |<>----------[ Application            ]   | STRING ext-restriction |<>--{0..*}--[ Description            ]   | ID observable-id       |<>--{0..*}--[ DetectionConfiguration ]   +------------------------+                   Figure 18: The DetectionPattern Class   The aggregate classes of the DetectionPattern class are:   Application      One.  SOFTWARE.  The application for which the      DetectionConfiguration or Description is being provided.   Description      Zero or more.  ML_STRING.  A free-form text description of how to      use the information provided in the Application or      DetectionConfiguration classes.   DetectionConfiguration      Zero or more.  STRING.  A machine-consumable configuration to find      a pattern of activity.   An instance of either the Description or DetectionConfiguration class   MUST be present.   The attributes of the DetectionPattern class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.Danyliw                      Standards Track                   [Page 40]

RFC 7970                     IODEF Version 2               November 2016   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.11.  Method Class   The Method class describes the tactics, techniques, procedures, or   weakness used by the threat actor in an incident.  This class   consists of both a list of references describing the attack methods   and weaknesses and a free-form text description.   +------------------------+   | Method                 |   +------------------------+   | ENUM restriction       |<>--{0..*}--[ Reference         ]   | STRING ext-restriction |<>--{0..*}--[ Description       ]   |                        |<>--{0..*}--[ sci:AttackPattern ]   |                        |<>--{0..*}--[ sci:Vulnerability ]   |                        |<>--{0..*}--[ sci:Weakness      ]   |                        |<>--{0..*}--[ AdditionalData    ]   +------------------------+                        Figure 19: The Method Class   The aggregate classes of the Method class are:   Reference      Zero or more.  A reference to a vulnerability, malware sample,      advisory, or analysis of an attack technique.  SeeSection 3.11.1.   Description      Zero or more.  ML_STRING.  A free-form text description of      techniques, tactics, or procedures used by the threat actor.   sci:AttackPattern      Zero or more.  A reference to a pattern of attack or exploitation      per [RFC7203].   sci:Vulnerability      Zero or more.  A reference to a vulnerability per [RFC7203].   sci:Weakness      Zero or more.  A reference to the exploited weakness per      [RFC7203].Danyliw                      Standards Track                   [Page 41]

RFC 7970                     IODEF Version 2               November 2016   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.   An instance of one of these children MUST be present.   The attributes of the Method class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.11.1.  Reference Class   The Reference class is an external reference to relevant information   such as a vulnerability, IDS alert, malware sample, advisory, or   attack technique.   +-------------------------+   | Reference               |   +-------------------------+   | ID observable-id        |<>--{0..1}--[ enum:ReferenceName ]   |                         |<>--{0..*}--[ URL                ]   |                         |<>--{0..*}--[ Description        ]   +-------------------------+                      Figure 20: The Reference Class   The aggregate classes of the Reference class are:   enum:ReferenceName      Zero or one.  Reference identifier per [RFC7495].   URL      Zero or more.  URL.  A URL to a reference.   Description      Zero or more.  ML_STRING.  A free-form text description of this      reference.   At least one of these classes MUST be present.Danyliw                      Standards Track                   [Page 42]

RFC 7970                     IODEF Version 2               November 2016   The attribute of the Reference class is:   observable-id      Optional.  ID.  SeeSection 3.3.2.3.12.  Assessment Class   The Assessment class describes the repercussions of the incident to   the victim.   +-------------------------+   | Assessment              |   +-------------------------+   | ENUM occurrence         |<>--{0..*}--[ IncidentCategory ]   | ENUM restriction        |<>--{0..*}--[ SystemImpact     ]   | STRING ext-restriction  |<>--{0..*}--[ BusinessImpact   ]   | ID observable-id        |<>--{0..*}--[ TimeImpact       ]   |                         |<>--{0..*}--[ MonetaryImpact   ]   |                         |<>--{0..*}--[ IntendedImpact   ]   |                         |<>--{0..*}--[ Counter          ]   |                         |<>--{0..*}--[ MitigatingFactor ]   |                         |<>--{0..*}--[ Cause            ]   |                         |<>--{0..1}--[ Confidence       ]   |                         |<>--{0..*}--[ AdditionalData   ]   +-------------------------+                      Figure 21: The Assessment Class   The aggregate classes of the Assessment class are:   IncidentCategory      Zero or more.  ML_STRING.  A free-form text description      categorizing the type of incident.   SystemImpact      Zero or more.  A technical characterization of the impact of the      incident activity on the victim's enterprise.  SeeSection 3.12.1.   BusinessImpact      Zero or more.  Impact of the incident activity on the business      functions of the victim organization.  SeeSection 3.12.2.   TimeImpact      Zero or more.  A characterization of the victim organization due      to the incident activity as a function of time.  SeeSection 3.12.3.Danyliw                      Standards Track                   [Page 43]

RFC 7970                     IODEF Version 2               November 2016   MonetaryImpact      Zero or more.  The financial loss due to the incident activity.      SeeSection 3.12.4.   IntendedImpact      Zero or more.  The intended outcome to the victim sought by the      threat actor.  Defined identically to the BusinessImpact defined      inSection 3.12.2 but describes intent rather than the realized      impact.   Counter      Zero or more.  A counter with which to summarize the magnitude of      the activity.  SeeSection 3.18.3.   MitigatingFactor      Zero or more.  ML_STRING.  A description of a mitigating factor      relative to the impact on the victim organization.   Cause      Zero or more.  ML_STRING.  A description of an underlying cause of      the impact.   Confidence      Zero or one.  An estimate of confidence in the impact assessment.      SeeSection 3.12.5.   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.   At least one instance of the possible five impact classes (i.e.,   SystemImpact, BusinessImpact, TimeImpact, MonetaryImpact, or   IntendedImpact) MUST be present.   The attributes of the Assessment class are:   occurrence      Optional.  ENUM.  Specifies whether the assessment is describing      actual or potential outcomes.      1.  actual.  This assessment describes activity that has occurred.      2.  potential.  This assessment describes potential activity that          might occur.   restriction      Optional.  ENUM.  SeeSection 3.3.1.Danyliw                      Standards Track                   [Page 44]

RFC 7970                     IODEF Version 2               November 2016   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.12.1.  SystemImpact Class   The SystemImpact class describes the technical impact of the incident   to the systems on the network.   +-----------------------+   | SystemImpact          |   +-----------------------+   | ENUM severity         |<>--{0..*}--[ Description ]   | ENUM completion       |   | ENUM type             |   | STRING ext-type       |   +-----------------------+                     Figure 22: The SystemImpact Class   The aggregate class of the SystemImpact class is:   Description      Zero or more.  ML_STRING.  A free-form text description of the      impact to the system.   The attributes of the SystemImpact class are:   severity      Optional.  ENUM.  An estimate of the relative severity of the      activity.  The permitted values are shown below.  There is no      default value.      1.  low.  Low severity      2.  medium.  Medium severity      3.  high.  High severityDanyliw                      Standards Track                   [Page 45]

RFC 7970                     IODEF Version 2               November 2016   completion      Optional.  ENUM.  An indication whether the described activity was      successful.  The permitted values are shown below.  There is no      default value.      1.  failed.  The attempted activity was not successful.      2.  succeeded.  The attempted activity succeeded.   type      Required.  ENUM.  Classifies the impact.  The permitted values are      shown below.  The default value is "unknown".  These values are      maintained in the "SystemImpact-type" IANA registry perSection 10.2.      1.   takeover-account.  Control was taken of a given account.      2.   takeover-service.  Control was taken of a given service.      3.   takeover-system.  Control was taken of a given system.      4.   cps-manipulation.  A cyber-physical system was manipulated.      5.   cps-damage.  A cyber-physical system was damaged.      6.   availability-data.  Access to particular data was degraded or           denied.      7.   availability-account.  Access to an account was degraded or           denied.      8.   availability-service.  Access to a service was degraded or           denied.      9.   availability-system.  Access to a system was degraded or           denied.      10.  damaged-system.  Hardware on a system was irreparably           damaged.      11.  damaged-data.  Data on a system was deleted.      12.  breach-proprietary.  Sensitive or proprietary information was           accessed or exfiltrated.      13.  breach-privacy.  Personally identifiable information was           accessed or exfiltrated.Danyliw                      Standards Track                   [Page 46]

RFC 7970                     IODEF Version 2               November 2016      14.  breach-credential.  Credential information was accessed or           exfiltrated.      15.  breach-configuration.  System configuration or data inventory           was access or exfiltrated.      16.  integrity-data.  Data on the system was modified.      17.  integrity-configuration.  Application or system configuration           was modified.      18.  integrity-hardware.  Firmware of a hardware component was           modified.      19.  traffic-redirection.  Network traffic on the system was           redirected      20.  monitoring-traffic.  Network traffic emerging from a host or           enclave was monitored.      21.  monitoring-host.  System activity (e.g., running processes,           keystrokes) were monitored.      22.  policy.  Activity violated the system owner's acceptable use           policy.      23.  unknown.  The impact is unknown.      24.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 47]

RFC 7970                     IODEF Version 2               November 20163.12.2.  BusinessImpact Class   The BusinessImpact class describes and characterizes the degree to   which the function of the organization was impacted by the incident.   +-------------------------+   | BusinessImpact          |   +-------------------------+   | ENUM severity           |<>--{0..*}--[ Description ]   | STRING ext-severity     |   | ENUM type               |   | STRING ext-type         |   +-------------------------+                    Figure 23: The BusinessImpact Class   The aggregate class of the BusinessImpact class is:   Description      Zero or more.  ML_STRING.  A free-form text description of the      impact to the organization.   The attributes of the BusinessImpact class are:   severity      Optional.  ENUM.  Characterizes the severity of the incident on      business functions.  The permitted values are shown below.  They      were derived from Table 3-2 of [NIST800.61rev2].  The default      value is "unknown".  These values are maintained in the      "BusinessImpact-severity" IANA registry perSection 10.2.      1.  none.  No effect to the organization's ability to provide all          services to all users.      2.  low.  Minimal effect as the organization can still provide all          critical services to all users but has lost efficiency.      3.  medium.  The organization has lost the ability to provide a          critical service to a subset of system users.      4.  high.  The organization is no longer able to provide some          critical services to any users.      5.  unknown.  The impact is not known.      6.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 48]

RFC 7970                     IODEF Version 2               November 2016   ext-severity      Optional.  STRING.  A means by which to extend the severity      attribute.  SeeSection 5.1.1.   type      Required.  ENUM.  Characterizes the effect this incident had on      the business.  The permitted values are shown below.  The default      value is "unknown".  These values are maintained in the      "BusinessImpact-type" IANA registry perSection 10.2.      1.   breach-proprietary.  Sensitive or proprietary information was           accessed or exfiltrated.      2.   breach-privacy.  Personally identifiable information was           accessed or exfiltrated.      3.   breach-credential.  Credential information was accessed or           exfiltrated.      4.   loss-of-integrity.  Sensitive or proprietary information was           changed or deleted.      5.   loss-of-service.  Service delivery was disrupted.      6.   theft-financial.  Money was stolen.      7.   theft-service.  Services were misappropriated.      8.   degraded-reputation.  The reputation of the organization's           brand was diminished.      9.   asset-damage.  A cyber-physical system was damaged.      10.  asset-manipulation.  A cyber-physical system was manipulated.      11.  legal.  The incident resulted in legal or regulatory action.      12.  extortion.  The incident resulted in actors extorting the           victim organization.      13.  unknown.  The impact is unknown.      14.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 49]

RFC 7970                     IODEF Version 2               November 2016   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.3.12.3.  TimeImpact Class   The TimeImpact class describes the impact of the incident on an   organization as a function of time.  It provides a way to convey down   time and recovery time.   +---------------------+   | TimeImpact          |   +---------------------+   | REAL                |   |                     |   | ENUM severity       |   | ENUM metric         |   | STRING ext-metric   |   | ENUM duration       |   | STRING ext-duration |   +---------------------+                      Figure 24: The TimeImpact Class   The content of the class is of type REAL and specifies an amount of   time.  The duration attribute provides units for this content, and   the metric attribute explains what this content is measuring.   The attributes of the TimeImpact class are:   severity      Optional.  ENUM.  An estimate of the relative severity of the      activity.  The permitted values are shown below.  There is no      default value.      1.  low.  Low severity      2.  medium.  Medium severity      3.  high.  High severity   metric      Required.  ENUM.  Defines the meaning of the value in the element      content.  These values are maintained in the "TimeImpact-metric"      IANA registry perSection 10.2.      1.  labor.  Total staff time to recovery from the activity (e.g.,          2 employees working 4 hours each would be 8 hours).Danyliw                      Standards Track                   [Page 50]

RFC 7970                     IODEF Version 2               November 2016      2.  elapsed.  Elapsed time from the beginning of the recovery to          its completion (i.e., wall-clock time).      3.  downtime.  Duration of time for which some provided service(s)          was not available.      4.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-metric      Optional.  STRING.  A means by which to extend the metric      attribute.  SeeSection 5.1.1.   duration      Optional.  ENUM.  Defines the unit of time for the value in the      element content.  The default value is "hour".  These values are      maintained in the "TimeImpact-duration" IANA registry perSection 10.2.      1.  second.  The unit of the element content is seconds.      2.  minute.  The unit of the element content is minutes.      3.  hour.  The unit of the element content is hours.      4.  day.  The unit of the element content is days.      5.  month.  The unit of the element content is months.      6.  quarter.  The unit of the element content is quarters.      7.  year.  The unit of the element content is years.      8.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-duration      Optional.  STRING.  A means by which to extend the duration      attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 51]

RFC 7970                     IODEF Version 2               November 20163.12.4.  MonetaryImpact Class   The MonetaryImpact class describes the financial impact of the   activity on an organization.  For example, this impact may consider   losses due to the cost of the investigation or recovery, diminished   productivity of the staff, or a tarnished reputation that will affect   future opportunities.   +------------------+   | MonetaryImpact   |   +------------------+   | REAL             |   |                  |   | ENUM severity    |   | STRING currency  |   +------------------+                    Figure 25: The MonetaryImpact Class   The content of the class is of type REAL and specifies a quantity of   money.  The currency attribute defines the currency of this value.   The attributes of the MonetaryImpact class are:   severity      Optional.  ENUM.  An estimate of the relative severity of the      activity.  The permitted values are shown below.  There is no      default value.      1.  low.  Low severity      2.  medium.  Medium severity      3.  high.  High severity   currency      Optional.  STRING.  Defines the currency in which the value in the      element content is expressed.  The permitted values are defined in      "Codes for the representation of currencies" [ISO4217].  There is      no default value.Danyliw                      Standards Track                   [Page 52]

RFC 7970                     IODEF Version 2               November 20163.12.5.  Confidence Class   The Confidence class represents an estimate of the validity and   accuracy of data expressed in the document.  This estimate can be   expressed as a category or a numeric calculation.   +-------------------+   | Confidence        |   +-------------------+   | REAL              |   |                   |   | ENUM rating       |   | STRING ext-rating |   +-------------------+                      Figure 26: The Confidence Class   The content of the class is of type REAL and specifies a numerical   assessment in the confidence of the data when the value of the rating   attribute is "numeric".  Otherwise, this element MUST be empty.   The attributes of the Confidence class are:   rating      Required.  ENUM.  A qualitative assessment of confidence.  These      values are maintained in the "Confidence-rating" IANA registry perSection 10.2      1.  low.  Low confidence.      2.  medium.  Medium confidence.      3.  high.  High confidence.      4.  numeric.  The element content contains a number that conveys          the confidence of the data.  The semantics of this number is          outside the scope of this specification.      5.  unknown.  The confidence rating value is not known.      6.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-rating      Optional.  STRING.  A means by which to extend the rating      attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 53]

RFC 7970                     IODEF Version 2               November 20163.13.  History Class   The History class is a log of the significant events or actions   performed by the involved parties during the course of handling the   incident.   The level of detail maintained in this log is left up to the   discretion of those handling the incident.   +------------------------+   | History                |   +------------------------+   | ENUM restriction       |<>--{1..*}--[ HistoryItem ]   | STRING ext-restriction |   +------------------------+                       Figure 27: The History Class   The aggregate classes of the History class are:   HistoryItem      One or more.  An entry in the history log of significant events or      actions performed by the involved parties.  SeeSection 3.13.1.   The attributes of the History class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.13.1.  HistoryItem Class   The HistoryItem class is an entry in the History (Section 3.13) log   that documents a particular action or event that occurred in the   course of handling the incident.  The details of the entry are a   free-form text description, but each can be categorized with the type   attribute.Danyliw                      Standards Track                   [Page 54]

RFC 7970                     IODEF Version 2               November 2016   +-------------------------+   | HistoryItem             |   +-------------------------+   | ENUM action             |<>----------[ DateTime       ]   | STRING ext-action       |<>--{0..1}--[ IncidentID     ]   | ENUM restriction        |<>--{0..1}--[ Contact        ]   | STRING ext-restriction  |<>--{0..*}--[ Description    ]   | ID observable-id        |<>--{0..*}--[ DefinedCOA     ]   |                         |<>--{0..*}--[ AdditionalData ]   +-------------------------+                     Figure 28: The HistoryItem Class   The aggregate classes of the HistoryItem class are:   DateTime      One.  DATETIME.  A timestamp of this entry in the history log.   IncidentID      Zero or one.  In a history log created by multiple parties, the      IncidentID provides a mechanism to specify which CSIRT created a      particular entry and references this organization's tracking      number.  When a single organization is maintaining the log, this      class can be ignored.  SeeSection 3.4.   Contact      Zero or one.  Provides contact information for the entity that      performed the action documented in this class.  SeeSection 3.9.   Description      Zero or more.  ML_STRING.  A free-form text description of the      action or event.   DefinedCOA      Zero or more.  STRING.  An identifier meaningful to the sender and      recipient of this document that references a course of action      (COA).  This class MUST be present if the action attribute is set      to "defined-coa".   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.Danyliw                      Standards Track                   [Page 55]

RFC 7970                     IODEF Version 2               November 2016   The attributes of the HistoryItem class are:   action      Required.  ENUM.  Classifies a performed action or occurrence      documented in this history log entry.  As activity will likely      have been instigated either through a previously conveyed      expectation or through an internal investigation, this attribute      is identical to the action attribute of the Expectation class.      The difference is only one of tense.  When an action is in this      class, it has been completed.  SeeSection 3.15.   ext-action      Optional.  STRING.  A means by which to extend the action      attribute.  SeeSection 5.1.1.   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.Danyliw                      Standards Track                   [Page 56]

RFC 7970                     IODEF Version 2               November 20163.14.  EventData Class   The EventData class is a container class to organize data about   events that occurred during an incident.   +-------------------------+   | EventData               |   +-------------------------+   | ENUM restriction        |<>--{0..*}--[ Description    ]   | STRING ext-restriction  |<>--{0..1}--[ DetectTime     ]   | ID observable-id        |<>--{0..1}--[ StartTime      ]   |                         |<>--{0..1}--[ EndTime        ]   |                         |<>--{0..1}--[ RecoveryTime   ]   |                         |<>--{0..1}--[ ReportTime     ]   |                         |<>--{0..*}--[ Contact        ]   |                         |<>--{0..*}--[ Discovery      ]   |                         |<>--{0..1}--[ Assessment     ]   |                         |<>--{0..*}--[ Method         ]   |                         |<>--{0..*}--[ Flow           ]   |                         |<>--{0..*}--[ Expectation    ]   |                         |<>--{0..1}--[ Record         ]   |                         |<>--{0..*}--[ EventData      ]   |                         |<>--{0..*}--[ AdditionalData ]   +-------------------------+                      Figure 29: The EventData Class   The aggregate classes of the EventData class are:   Description      Zero or more.  ML_STRING.  A free-form text description of the      event.   DetectTime      Zero or one.  DATETIME.  The time the event was detected.   StartTime      Zero or one.  DATETIME.  The time the event started.   EndTime      Zero or one.  DATETIME.  The time the event ended.   RecoveryTime      Zero or one.  DATETIME.  The time the site recovered from the      event.   ReportTime      Zero or one.  DATETIME.  The time the event was reported.Danyliw                      Standards Track                   [Page 57]

RFC 7970                     IODEF Version 2               November 2016   Contact      Zero or more.  Contact information for the parties involved in the      event.  SeeSection 3.9.   Discovery      Zero or more.  The means by which the event was detected.  SeeSection 3.10.   Assessment      Zero or one.  The impact of the event on the victim and the      actions taken.  SeeSection 3.12.   Method      Zero or more.  The technique used by the threat actor in the      event.  SeeSection 3.11.   Flow      Zero or more.  A description of the systems or networks involved.      SeeSection 3.16.   Expectation      Zero or more.  The expected action to be performed by the      recipient for the described event.  SeeSection 3.15.   Record      Zero or one.  Supportive data (e.g., log files) that provides      additional information about the event.  SeeSection 3.22.   EventData      Zero or more.  A recursive definition of the EventData class.  SeeSection 3.14.2 for an explanation on using this class.   AdditionalData      Zero or more.  EXTENSION.  An extension mechanism for data not      explicitly represented in the data model.   At least one of the aggregate classes MUST be present in an instance   of the EventData class.   The attributes of the EventData class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.  The default value is      "default".   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 58]

RFC 7970                     IODEF Version 2               November 2016   observable-id      Optional.  ID.  SeeSection 3.3.2.3.14.1.  Relating the Incident and EventData Classes   There is substantial overlap in the child classes aggregated in the   Incident and EventData classes.  Nevertheless, the semantics of these   classes are quite different.  The Incident class provides summary   information about the entire incident, while the EventData class   provides information about the individual events comprising the   incident.  In the common case, the EventData class will provide more   specific information for the general description provided in the   Incident class.  However, in the case where the summarized   information in the Incident class conflicts with the detailed   information in an EventData class, the more specific EventData class   MUST supersede the more generic information provided in the Incident   class.3.14.2.  Recursive Definition of EventData   The EventData class is a container for the properties of an event in   an incident.  These properties include: the hosts involved, impact of   the incident activity on the hosts, forensic logs, etc.  The   recursive definition of EventData allows for the grouping of related   information with common properties.  This approach eliminates the   need for explicit identifiers to relate information or duplicate it.   Instead, the relative depth (nesting) of a class is used to group   (relate) information.   For example, consider a case where two hosts experience different   impacts during an incident.  However, these two hosts have common   contact information.  A depiction of how this situation would be   represented can be found in Figure 30.  EventData (2) and (3) group   each of the two hosts with their unique impact.  EventData (1)   describes the common Contact class these two hosts share.Danyliw                      Standards Track                   [Page 59]

RFC 7970                     IODEF Version 2               November 2016   +------------------+   | EventData (1)    |   +------------------+   |                  |<>----[ Contact    ]   |                  |   |                  |<>----[ EventData (2) ]<>----[ Flow       ]   |                  |      [               ]<>----[ Assessment ]   |                  |   |                  |<>----[ EventData (3) ]<>----[ Flow       ]   |                  |      [               ]<>----[ Assessment ]   +------------------+                Figure 30: Recursion in the EventData Class3.15.  Expectation Class   The Expectation class conveys to the recipient of the IODEF document   the actions the sender is requesting.   +-------------------------+   | Expectation             |   +-------------------------+   | ENUM action             |<>--{0..*}--[ Description ]   | STRING ext-action       |<>--{0..*}--[ DefinedCOA  ]   | ENUM severity           |<>--{0..1}--[ StartTime   ]   | ENUM restriction        |<>--{0..1}--[ EndTime     ]   | STRING ext-restriction  |<>--{0..1}--[ Contact     ]   | ID observable-id        |   +-------------------------+                     Figure 31: The Expectation Class   The aggregate classes of the Expectation class are:   Description      Zero or more.  ML_STRING.  A free-form text description of the      desired action(s).   DefinedCOA      Zero or more.  STRING.  A unique identifier meaningful to the      sender and recipient of this document that references a course of      action.  This class MUST be present if the action attribute is set      to "defined-coa".Danyliw                      Standards Track                   [Page 60]

RFC 7970                     IODEF Version 2               November 2016   StartTime      Zero or one.  DATETIME.  The time at which the sender would like      the action performed.  A timestamp that is earlier than the      ReportTime specified in the Incident class denotes that the sender      would like the action performed as soon as possible.  The absence      of this element indicates no expectations of when the recipient      would like the action performed.   EndTime      Zero or one.  DATETIME.  The time by which the sender expects the      recipient to complete the action.  If the recipient cannot      complete the action before EndTime, the recipient MUST NOT carry      out the action.  Because of transit delays and clock drift, the      sender MUST be prepared for the recipient to have carried out the      action, even if it completes past EndTime.   Contact      Zero or one.  The entity expected to perform the action.  SeeSection 3.9.   The attributes of the Expectation class are:   action      Optional.  ENUM.  Classifies the type of action requested.  The      default value of "other".  These values are maintained in the      "Expectation-action" IANA registry perSection 10.2.      1.   nothing.  No action is requested.  Do nothing with the           information.      2.   contact-source-site.  Contact the site(s) identified as the           source of the activity.      3.   contact-target-site.  Contact the site(s) identified as the           target of the activity.      4.   contact-sender.  Contact the originator of the document.      5.   investigate.  Investigate the system(s) listed in the event.      6.   block-host.  Block traffic from the machine(s) listed as           sources in the event.      7.   block-network.  Block traffic from the network(s) lists as           sources in the event.      8.   block-port.  Block the port listed as sources in the event.Danyliw                      Standards Track                   [Page 61]

RFC 7970                     IODEF Version 2               November 2016      9.   rate-limit-host.  Rate-limit the traffic from the machine(s)           listed as sources in the event.      10.  rate-limit-network.  Rate-limit the traffic from the           network(s) lists as sources in the event.      11.  rate-limit-port.  Rate-limit the port(s) listed as sources in           the event.      12.  redirect-traffic.  Redirect traffic from the intended           recipient for further analysis.      13.  honeypot.  Redirect traffic from systems listed in the event           to a honeypot for further analysis.      14.  upgrade-software.  Upgrade or patch the software or firmware           on an asset listed in the event.      15.  rebuild-asset.  Reinstall the operating system or           applications on an asset listed in the event.      16.  harden-asset.  Change the configuration of an asset listed in           the event to reduce the attack surface.      17.  remediate-other.  Remediate the activity in a way other than           by rate-limiting or blocking.      18.  status-triage.  Confirm receipt and begin triaging the           incident.      19.  status-new-info.  Notify the sender when new information is           received for this incident.      20.  watch-and-report.  Watch for the described activity or           indicators, and notify the sender when seen.      21.  training.  Train user to identify or mitigate the described           threat.      22.  defined-coa.  Perform a predefined course of action (COA).           The COA is named in the DefinedCOA class.      23.  other.  Perform a custom action described in the Description           class.      24.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 62]

RFC 7970                     IODEF Version 2               November 2016   ext-action      Optional.  STRING.  A means by which to extend the action      attribute.  SeeSection 5.1.1.   severity      Optional.  ENUM.  Indicates the desired priority of the action.      This attribute is an enumerated list with no default value, and      the semantics of these relative measures are context dependent.      1.  low.  Low priority      2.  medium.  Medium priority      3.  high.  High priority   restriction      Optional.  ENUM.  SeeSection 3.3.1.  The default value is      "default".   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.16.  Flow Class   The Flow class describes the systems and networks involved in the   incident and the relationships between them.   +------------------+   | Flow             |   +------------------+   |                  |<>--{1..*}--[ System   ]   +------------------+                         Figure 32: The Flow Class   The aggregate class of the Flow class is:   System      One or More.  A host or network involved in an event.  SeeSection 3.17.   The Flow class has no attributes.Danyliw                      Standards Track                   [Page 63]

RFC 7970                     IODEF Version 2               November 20163.17.  System Class   The System class describes a system or network involved in an event.   +------------------------+   | System                 |   +------------------------+   | ENUM category          |<>----------[ Node            ]   | STRING ext-category    |<>--{0..*}--[ NodeRole        ]   | STRING interface       |<>--{0..*}--[ Service         ]   | ENUM spoofed           |<>--{0..*}--[ OperatingSystem ]   | ENUM virtual           |<>--{0..*}--[ Counter         ]   | ENUM ownership         |<>--{0..*}--[ AssetID         ]   | STRING ext-ownership   |<>--{0..*}--[ Description     ]   | ENUM restriction       |<>--{0..*}--[ AdditionalData  ]   | STRING ext-restriction |   | ID observable-id       |   +------------------------+                        Figure 33: The System Class   The aggregate classes of the System class are:   Node      One.  A host or network involved in the incident.  SeeSection 3.18.   NodeRole      Zero or more.  The intended purpose of the system.  SeeSection 3.18.2.   Service      Zero or more.  A network service running on the system.  SeeSection 3.20.   OperatingSystem      Zero or more.  SOFTWARE.  The operating system running on the      system.   Counter      Zero or more.  A counter with which to summarize properties of      this host or network.  SeeSection 3.18.3.   AssetID      Zero or more.  STRING.  An asset identifier for the System.Danyliw                      Standards Track                   [Page 64]

RFC 7970                     IODEF Version 2               November 2016   Description      Zero or more.  ML_STRING.  A free-form text description of the      System.   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.   The attributes of the System class are:   category      Optional.  ENUM.  Classifies the role the host or network played      in the incident.  These values are maintained in the "System-      category" IANA registry perSection 10.2.      1.  source.  The System was the source of the event.      2.  target.  The System was the target of the event.      3.  intermediate.  The System was an intermediary in the event.      4.  sensor.  The System was a sensor monitoring the event.      5.  infrastructure.  The System was an infrastructure node of the          IODEF document exchange.      6.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-category      Optional.  STRING.  A means by which to extend the category      attribute.  SeeSection 5.1.1.   interface      Optional.  STRING.  Specifies the interface on which the event(s)      on this System originated.  If the Node class specifies a network      rather than a host, this attribute has no meaning.   spoofed      Optional.  ENUM.  An indication of confidence in whether this      System was the true target or attacking host.  The permitted      values for this attribute are shown below.  The default value is      "unknown".      1.  unknown.  The accuracy of the category attribute value is          unknown.Danyliw                      Standards Track                   [Page 65]

RFC 7970                     IODEF Version 2               November 2016      2.  yes.  The category attribute value is likely incorrect.  In          the case of a source, the System is likely a decoy; with a          target, the System was likely not the intended victim.      3.  no.  The category attribute value is believed to be correct.   virtual      Optional.  ENUM.  Indicates whether this System is a virtual or      physical device.  The default value is "unknown".      1.  yes.  The System is a virtual device.      2.  no.  The System is a physical device.      3.  unknown.  It is not known if the System is virtual.   ownership      Optional.  ENUM.  Describes the ownership of this System relative      to the victim in the incident.  These values are maintained in the      "System-ownership" IANA registry perSection 10.2.      1.  organization.  Corporate or enterprise owned.      2.  personal.  Personally owned by an employee or affiliate of the          corporation or enterprise.      3.  partner.  Owned by a partner of the corporation or enterprise.      4.  customer.  Owned by a customer of the corporation or          enterprise.      5.  no-relationship.  Owned by an entity that has no known          relationship with the victim organization.      6.  unknown.  Ownership is unknown.      7.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-ownership      Optional.  STRING.  A means by which to extend the ownership      attribute.  SeeSection 5.1.1.   restriction      Optional.  ENUM.  SeeSection 3.3.1.Danyliw                      Standards Track                   [Page 66]

RFC 7970                     IODEF Version 2               November 2016   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.18.  Node Class   The Node class identifies a system, asset, or network and its   location.   +---------------+   | Node          |   +---------------+   |               |<>--{0..*}--[ DomainData    ]   |               |<>--{0..*}--[ Address       ]   |               |<>--{0..1}--[ PostalAddress ]   |               |<>--{0..*}--[ Location      ]   |               |<>--{0..*}--[ Counter       ]   +---------------+                         Figure 34: The Node Class   The aggregate classes of the Node class are:   DomainData      Zero or more.  The domain (DNS) information associated with this      node.  If an Address is not provided, at least one DomainData MUST      be specified.  SeeSection 3.19.   Address      Zero or more.  The hardware, network, or application address of      the node.  If a DomainData is not provided, at least one Address      MUST be specified.  SeeSection 3.18.1.   PostalAddress      Zero or one.  POSTAL.  The postal address of the node.   Location      Zero or more.  ML_STRING.  A free-form text description of the      physical location of the node.  This description may provide a      more detailed description of where at the address specified by the      PostalAddress class this node is found (e.g., room number, rack      number, or slot number in a chassis).Danyliw                      Standards Track                   [Page 67]

RFC 7970                     IODEF Version 2               November 2016   Counter      Zero or more.  A counter with which to summarize properties of      this host or network.  SeeSection 3.18.3.   The Node class has no attributes.3.18.1.  Address Class   The Address class represents a hardware (Layer 2), network (Layer 3),   or application (Layer 7) address.   +-------------------------+   | Address                 |   +-------------------------+   | STRING                  |   |                         |   | ENUM category           |   | STRING ext-category     |   | STRING vlan-name        |   | INTEGER vlan-num        |   | ID observable-id        |   +-------------------------+                       Figure 35: The Address Class   The content of the class is an address of type STRING whose semantics   are determined by the category attribute.   The attributes of the Address class are:   category      Required.  ENUM.  The type of address represented.  The default      value is "ipv6-addr".  These values are maintained in the      "Address-category" IANA registry perSection 10.2.      1.   asn.  Autonomous System Number.      2.   atm.  Asynchronous Transfer Mode (ATM) address.      3.   e-mail.  Email address, per the EMAIL data type.      4.   ipv4-addr.  IPv4 host address in dotted-decimal notation           (i.e., a.b.c.d).      5.   ipv4-net.  IPv4 network address in dotted-decimal notation,           slash, significant bits (i.e., a.b.c.d/nn).Danyliw                      Standards Track                   [Page 68]

RFC 7970                     IODEF Version 2               November 2016      6.   ipv4-net-masked.  A sanitized IPv4 address with significant           bits per "ipv4-net" but with the character 'x' replacing any           digit(s) in the address or prefix.      7.   ipv4-net-mask.  IPv4 network address in dotted-decimal           notation, slash, network mask in dotted-decimal notation           (i.e., a.b.c.d/w.x.y.z).      8.   ipv6-addr.  IPv6 host address perSection 4 of [RFC5952].      9.   ipv6-net.  IPv6 network address, slash, prefix perSection 2.3 of [RFC4291].      10.  ipv6-net-masked.  A sanitized IPv6 address and prefix per           "ipv6-net" but with the character 'x' replacing any           hexadecimal digit(s) in the address or digit(s) in the           prefix.      11.  mac.  Media Access Control (MAC) address (i.e.,           aa:bb:cc:dd:ee:ff).      12.  site-uri.  A URL or URI for a resource, per the URL data           type.      13.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-category      Optional.  STRING.  A means by which to extend the category      attribute.  SeeSection 5.1.1.   vlan-name      Optional.  STRING.  The name of the Virtual LAN to which the      address belongs.   vlan-num      Optional.  INTEGER.  The number of the Virtual LAN to which the      address belongs.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.18.2.  NodeRole Class   The NodeRole class describes the function performed by or role of a   particular system, asset, or network.Danyliw                      Standards Track                   [Page 69]

RFC 7970                     IODEF Version 2               November 2016   +-----------------------+   | NodeRole              |   +-----------------------+   | ENUM category         |<>--{0..*}--[ Description ]   | STRING ext-category   |   +-----------------------+                       Figure 36: The NodeRole Class   The aggregate class of the NodeRole class is:   Description      Zero or more.  ML_STRING.  A free-form text description of the      role of the system.   The attributes of the NodeRole class are:   category      Required.  ENUM.  Function or role of a node.  These values are      maintained in the "NodeRole-category" IANA registry perSection 10.2.      1.   client.  Client computer.      2.   client-enterprise.  Client computer on the enterprise           network.      3.   client-partner.  Client computer on network of a partner.      4.   client-remote.  Client computer remotely connected to the           enterprise network.      5.   client-kiosk.  Client computer serving as a kiosk.      6.   client-mobile.  Mobile device.      7.   server-internal.  Server with internal services.      8.   server-public.  Server with public services.      9.   www.  WWW server.      10.  mail.  Mail server.      11.  webmail.  Web mail server.      12.  messaging.  Messaging server (e.g., NNTP, IRC, IM).Danyliw                      Standards Track                   [Page 70]

RFC 7970                     IODEF Version 2               November 2016      13.  streaming.  Streaming-media server.      14.  voice.  Voice server (e.g., SIP, H.323).      15.  file.  File server.      16.  ftp.  FTP server.      17.  p2p.  Peer-to-peer node.      18.  name.  Name server (e.g., DNS, WINS).      19.  directory.  Directory server (e.g., LDAP, finger, whois).      20.  credential.  Credential server (e.g., domain controller,           Kerberos).      21.  print.  Print server.      22.  application.  Application server.      23.  database.  Database server.      24.  backup.  Backup server.      25.  dhcp.  DHCP server.      26.  assessment.  Assessment server (e.g., vulnerability scanner,           endpoint assessment).      27.  source-control.  Source code control server.      28.  config-management.  Configuration management server.      29.  monitoring.  Security monitoring server (e.g., IDS).      30.  infra.  Infrastructure server (e.g., router, firewall, DHCP).      31.  infra-firewall.  Firewall.      32.  infra-router.  Router.      33.  infra-switch.  Switch.      34.  camera.  Camera and video system.      35.  proxy.  Proxy server.Danyliw                      Standards Track                   [Page 71]

RFC 7970                     IODEF Version 2               November 2016      36.  remote-access.  Remote access server.      37.  log.  Log server (e.g., syslog).      38.  virtualization.  Server running virtual machines.      39.  pos.  Point-of-sale device.      40.  scada.  Supervisory control and data acquisition (SCADA)           system.      41.  scada-supervisory.  Supervisory system for a SCADA.      42.  sinkhole.  Traffic sinkhole destination.      43.  honeypot.  Honeypot server.      44.  anonymization.  Anonymization server (e.g., Tor node).      45.  c2-server.  Malicious command and control server.      46.  malware-distribution.  Server that distributes malware      47.  drop-server.  Server to which exfiltrated content is           uploaded.      48.  hop-point.  Intermediary server used to get to a victim.      49.  reflector.  A system used in a reflector attack.      50.  phishing-site.  Site hosting phishing content.      51.  spear-phishing-site.  Site hosting spear-phishing content.      52.  recruiting-site.  Site to recruit.      53.  fraudulent-site.  Fraudulent site.      54.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-category      Optional.  STRING.  A means by which to extend the category      attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 72]

RFC 7970                     IODEF Version 2               November 20163.18.3.  Counter Class   The Counter class summarizes multiple occurrences of an event or   conveys counts or rates of various features.   The complete semantics of this class are context dependent based on   the class in which it is aggregated.   +---------------------+   | Counter             |   +---------------------+   | REAL                |   |                     |   | ENUM type           |   | STRING ext-type     |   | ENUM unit           |   | STRING ext-unit     |   | STRING meaning      |   | ENUM duration       |   | STRING ext-duration |   +---------------------+                       Figure 37: The Counter Class   The content of the class is a value of type REAL whose meaning and   units are determined by the type and duration attributes,   respectively.  If the duration attribute is present, the element   content is a rate.  Otherwise, it is a simple counter.   The attributes of the Counter class are:   type      Required.  ENUM.  Specifies the type of counter specified in the      element content.  These values are maintained in the "Counter-      type" IANA registry perSection 10.2.      1.  count.  The Counter class value is a counter.      2.  peak.  The Counter class value is a peak value.      3.  average.  The Counter class value is an average.      4.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 73]

RFC 7970                     IODEF Version 2               November 2016   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.   unit      Required.  ENUM.  Specifies the units of the element content.      These values are maintained in the "Counter-unit" IANA registry      perSection 10.2.      1.   byte.  Bytes transferred.      2.   mbit.  Megabits (Mbits) transferred.      3.   packet.  Packets.      4.   flow.  Network flow records.      5.   session.  Sessions.      6.   alert.  Notifications generated by another system (e.g., IDS           or SIEM system).      7.   message.  Messages (e.g., mail messages).      8.   event.  Events.      9.   host.  Hosts.      10.  site.  Site.      11.  organization.  Organizations.      12.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-unit      Optional.  STRING.  A means by which to extend the unit attribute.      SeeSection 5.1.1.   meaning      Optional.  STRING.  A free-form text description of the metric      represented by the Counter.Danyliw                      Standards Track                   [Page 74]

RFC 7970                     IODEF Version 2               November 2016   duration      Optional.  ENUM.  If present, the Counter class represents a rate.      This attribute specifies a unit of time over which the rate whose      units are specified in the unit attribute is being conveyed.  This      attribute is the denominator of the rate (where the unit attribute      specified the nominator).  The possible values of this attribute      are defined in the duration attribute ofSection 3.12.3   ext-duration      Optional.  STRING.  A means by which to extend the duration      attribute.  SeeSection 5.1.1.3.19.  DomainData Class   The DomainData class describes a domain name and metadata associated   with this domain.   +--------------------------+   | DomainData               |   +--------------------------+   | ENUM system-status       |<>----------[ Name                 ]   | STRING ext-system-status |<>--{0..1}--[ DateDomainWasChecked ]   | ENUM domain-status       |<>--{0..1}--[ RegistrationDate     ]   | STRING ext-domain-status |<>--{0..1}--[ ExpirationDate       ]   | ID observable-id         |<>--{0..*}--[ RelatedDNS           ]   |                          |<>--{0..*}--[ Nameservers          ]   |                          |<>--{0..1}--[ DomainContacts       ]   +--------------------------+                      Figure 38: The DomainData Class   The aggregate classes of the DomainData class are:   Name      One.  STRING.  The domain name of a system.   DateDomainWasChecked      Zero or one.  DATETIME.  A timestamp of when the domain listed in      the Name class was resolved.   RegistrationDate      Zero or one.  DATETIME.  A timestamp of when domain listed in the      Name class was registered.   ExpirationDate      Zero or one.  DATETIME.  A timestamp of when the domain listed in      the Name class is set to expire.Danyliw                      Standards Track                   [Page 75]

RFC 7970                     IODEF Version 2               November 2016   RelatedDNS      Zero or more.  EXTENSION.  Additional DNS records associated with      this domain.   Nameservers      Zero or more.  The nameservers identified for the domain listed in      the Name class.  SeeSection 3.19.1.   DomainContacts      Zero or one.  Contact information for the domain listed in the      Name class supplied by the registrar or through a whois query.   The attributes of the DomainData class are:   system-status      Required.  ENUM.  Assesses the domain's involvement in the event.      These values are maintained in the "DomainData-system-status" IANA      registry perSection 10.2.      1.  spoofed.  This domain was spoofed.      2.  fraudulent.  This domain was operated with fraudulent          intentions.      3.  innocent-hacked.  This domain was compromised by a third          party.      4.  innocent-hijacked.  This domain was deliberately hijacked.      5.  unknown.  No categorization for this domain known.      6.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-system-status      Optional.  STRING.  A means by which to extend the system-status      attribute.  SeeSection 5.1.1.   domain-status      Required.  ENUM.  Categorizes the registry status of the domain at      the time the document was generated.  These values and their      associated descriptions are derived fromSection 3.2.2 of      [RFC3982].  These values are maintained in the      "DomainData-domain-status" IANA registry perSection 10.2.      1.   reservedDelegation.  The domain is permanently inactive.Danyliw                      Standards Track                   [Page 76]

RFC 7970                     IODEF Version 2               November 2016      2.   assignedAndActive.  The domain is in a normal state.      3.   assignedAndInactive.  The domain has an assigned           registration, but the delegation is inactive.      4.   assignedAndOnHold.  The domain is in dispute.      5.   revoked.  The domain is in the process of being purged from           the database.      6.   transferPending.  The domain is pending a change in           authority.      7.   registryLock.  The domain is on hold by the registry.      8.   registrarLock.  Same as "registryLock".      9.   other.  The domain has a known status, but it is not one of           the redefined enumerated values.      10.  unknown.  The domain has an unknown status.      11.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-domain-status      Optional.  STRING.  A means by which to extend the domain-status      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.19.1.  Nameservers Class   The Nameservers class describes the nameservers associated with a   given domain.   +--------------------+   | Nameservers        |   +--------------------+   |                    |<>----------[ Server  ]   |                    |<>--{1..*}--[ Address ]   +--------------------+                     Figure 39: The Nameservers ClassDanyliw                      Standards Track                   [Page 77]

RFC 7970                     IODEF Version 2               November 2016   The aggregate classes of the Nameservers class are:   Server      One.  STRING.  The domain name of the nameserver.   Address      One or more.  The address of the nameserver.  The value of the      category attribute MUST be either "ipv4-addr" or "ipv6-addr".  SeeSection 3.18.1.   The Nameservers class has no attributes.3.19.2.  DomainContacts Class   The DomainContacts class describes the contact information for a   given domain provided either by the registrar or through a whois   query.   This contact information can be explicitly described through a   Contact class, or a reference can be provided to a domain with   identical contact information.  Either a single SameDomainContact or   one or more Contact classes MUST be present.   +--------------------+   | DomainContacts     |   +--------------------+   |                    |<>--{0..1}--[ SameDomainContact ]   |                    |<>--{1..*}--[ Contact ]   +--------------------+                    Figure 40: The DomainContacts Class   The aggregate classes of the DomainContacts class are:   SameDomainContact      Zero or one.  STRING.  A domain name already cited in this      document or through previous exchange that contains the identical      contact information as the domain name in question.  The domain      contact information associated with this domain should be used      instead of an explicit definition with the Contact class.   Contact      One or more.  Contact information for the domain.  SeeSection 3.9.   The DomainContacts class has no attributes.Danyliw                      Standards Track                   [Page 78]

RFC 7970                     IODEF Version 2               November 20163.20.  Service Class   The Service class describes a network service.  The service is   described by a protocol, port, protocol header field, and application   providing or using the service.   +-------------------------+   | Service                 |   +-------------------------+   | INTEGER ip-protocol     |<>--{0..1}--[ ServiceName       ]   | ID observable-id        |<>--{0..1}--[ Port              ]   |                         |<>--{0..1}--[ Portlist          ]   |                         |<>--{0..1}--[ ProtoCode         ]   |                         |<>--{0..1}--[ ProtoType         ]   |                         |<>--{0..1}--[ ProtoField        ]   |                         |<>--{0..1}--[ ApplicationHeader ]   |                         |<>--{0..1}--[ EmailData         ]   |                         |<>--{0..1}--[ Application       ]   +-------------------------+                       Figure 41: The Service Class   The aggregate classes of the Service class are:   ServiceName      Zero or one.  A protocol name.   Port      Zero or one.  INTEGER.  A port number.   Portlist      Zero or one.  PORTLIST.  A list of port numbers.   ProtoCode      Zero or one.  INTEGER.  A transport-layer (Layer 4) protocol-      specific code field (e.g., ICMP code field).   ProtoType      Zero or one.  INTEGER.  A transport-layer (Layer 4) protocol-      specific type field (e.g., ICMP type field).   ProtoField      Zero or one.  INTEGER.  A transport-layer (Layer 4) protocol-      specific flag field (e.g., TCP flag field).   ApplicationHeader      Zero or one.  A protocol header.  SeeSection 3.20.2.Danyliw                      Standards Track                   [Page 79]

RFC 7970                     IODEF Version 2               November 2016   EmailData      Zero or one.  Headers associated with an email message.  SeeSection 3.21.   Application      Zero or one.  SOFTWARE.  The application acting as either the      client or the server for the service.   At least one of these classes MUST be present.   When a given System class with category="source" and another with   category="target" are aggregated into a single Flow class, and each   of these System classes has a Service and Portlist class, an implicit   relationship between these Portlists exists.  If N ports are listed   for a System@category="source", and M ports are listed for   System@category="target", the number of ports in N must be equal to   M.  Likewise, the ports MUST be listed in an identical sequence such   that the n-th port in the source corresponds to the n-th port of the   target.  If N is greater than 1, a given instance of a Flow class   MUST only have a single instance of a System@category="source" and   System@category="target".   The attributes of the Service class are:   ip-protocol      Optional.  INTEGER.  The IANA-assigned IP protocol number per      [IANA.Protocols].  The attribute MUST be set if a Port, Portlist,      ProtoCode, ProtoType, or ProtoField class is present.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.20.1.  ServiceName Class   The ServiceName class identifies an application protocol.  It can be   described by referencing an IANA-registered protocol, by referencing   a URL, or with free-form text.   +--------------------+   | ServiceName        |   +--------------------+   |                    |<>--{0..1}--[ IANAService       ]   |                    |<>--{0..*}--[ URL               ]   |                    |<>--{0..*}--[ Description       ]   +--------------------+                     Figure 42: The ServiceName ClassDanyliw                      Standards Track                   [Page 80]

RFC 7970                     IODEF Version 2               November 2016   The aggregate classes of the ServiceName class are:   IANAService      Zero or one.  STRING.  The name of the service per the "Service      Name" field of the registry [IANA.Ports].   URL      Zero or more.  URL.  A URL to a resource describing the service.   Description      Zero or more.  ML_STRING.  A free-form text description of the      service.   At least one of these classes MUST be present.   The ServiceName class has no attributes.3.20.2.  ApplicationHeader Class   The ApplicationHeader class describes arbitrary fields from a   protocol header and its corresponding value.   +--------------------------+   | ApplicationHeader        |   +--------------------------+   |                          |<>--{1..*}--[ ApplicationHeaderField ]   +--------------------------+                  Figure 43: The ApplicationHeader Class   The aggregate class of the ApplicationHeader class is:   ApplicationHeaderField      One or more.  EXTENSION.  A field name and value in a protocol      header.  The name attribute MUST be set to the field name.  The      field value MUST be set in the element content.   The ApplicationHeader class has no attributes.Danyliw                      Standards Track                   [Page 81]

RFC 7970                     IODEF Version 2               November 20163.21.  EmailData Class   The EmailData class describes headers from an email message and   cryptographic hashes and signatures applied to it.   +-------------------------+   | EmailData               |   +-------------------------+   | ID observable-id        |<>--{0..*}--[ EmailTo          ]   |                         |<>--{0..1}--[ EmailFrom        ]   |                         |<>--{0..1}--[ EmailSubject     ]   |                         |<>--{0..1}--[ EmailX-Mailer    ]   |                         |<>--{0..*}--[ EmailHeaderField ]   |                         |<>--{0..1}--[ EmailHeaders     ]   |                         |<>--{0..1}--[ EmailBody        ]   |                         |<>--{0..1}--[ EmailMessage     ]   |                         |<>--{0..*}--[ HashData         ]   |                         |<>--{0..*}--[ SignatureData    ]   +-------------------------+                        Figure 44: EmailData Class   The aggregate classes of the EmailData class are:   EmailTo      Zero or more.  EMAIL.  The value of the "To:" header field      (Section 3.6.3 of [RFC5322]) in an email.   EmailFrom      Zero or one.  EMAIL.  The value of the "From:" header field      (Section 3.6.2 of [RFC5322]) in an email.   EmailSubject      Zero or one.  STRING.  The value of the "Subject:" header field in      an email.  SeeSection 3.6.5 of [RFC5322].   EmailX-Mailer      Zero or one.  STRING.  The value of the "X-Mailer:" header field      in an email.   EmailHeaderField      Zero or more.  EXTENSION.  The header name and value of an      arbitrary header field of the email message.  The name attribute      MUST be set to the header name.  The header value MUST be set in      the element body.  The dtype attribute MUST be set to "string".   EmailHeaders      Zero or one.  STRING.  The headers of an email message.Danyliw                      Standards Track                   [Page 82]

RFC 7970                     IODEF Version 2               November 2016   EmailBody      Zero or one.  STRING.  The body of an email message.   EmailMessage      Zero or one.  STRING.  The headers and body of an email message.   HashData      Zero or more.  Hash(es) associated with this email message.  SeeSection 3.26.   SignatureData      Zero or more.  Signature(s) associated with this email message.      SeeSection 3.27.   The attribute of the EmailData class is:   observable-id      Optional.  ID.  SeeSection 3.3.2.3.22.  Record Class   The Record class is a container class for log and audit data that   provides supportive information about the events in an incident.  The   source of this data will often be the output of monitoring tools.   These logs substantiate the activity described in the document.   +------------------------+   | Record                 |   +------------------------+   | ENUM restriction       |<>--{1..*}--[ RecordData ]   | STRING ext-restriction |   +------------------------+                        Figure 45: The Record Class   The aggregate classes of the Record class are:   RecordData      One or more.  Log or audit data generated by a particular tool.      Separate instances of the RecordData class SHOULD be used for each      type of log.  SeeSection 3.22.1.   The attributes of the Record class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.Danyliw                      Standards Track                   [Page 83]

RFC 7970                     IODEF Version 2               November 2016   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.22.1.  RecordData Class   The RecordData class describes or references log or audit data from a   given type of tool and provides a means to annotate the output.   +------------------------+   | RecordData             |   +------------------------+   | ENUM restriction       |<>--{0..1}--[ DateTime               ]   | STRING ext-restriction |<>--{0..*}--[ Description            ]   | ID observable-id       |<>--{0..1}--[ Application            ]   |                        |<>--{0..*}--[ RecordPattern          ]   |                        |<>--{0..*}--[ RecordItem             ]   |                        |<>--{0..*}--[ URL                    ]   |                        |<>--{0..*}--[ FileData               ]   |                        |<>--{0..*}--   |                        |       [ WindowsRegistryKeysModified ]   |                        |<>--{0..*}--[ CertificateData        ]   |                        |<>--{0..*}--[ AdditionalData         ]   +------------------------+                      Figure 46: The RecordData Class   The aggregate classes of the RecordData class are:   DateTime      Zero or one.  DATETIME.  A timestamp of the data found in the      RecordItem or URL classes.   Description      Zero or more.  ML_STRING.  A free-form text description of the      data provided in the RecordItem or URL classes.   Application      Zero or one.  SOFTWARE.  Identifies the tool used to generate the      data in the RecordItem or URL classes.   RecordPattern      Zero or more.  A search string to precisely find the relevant data      in the RecordItem or URL classes.  SeeSection 3.22.2.   RecordItem      Zero or more.  EXTENSION.  Log, audit, or forensic data to support      the conclusions made during the course of analyzing the incident.Danyliw                      Standards Track                   [Page 84]

RFC 7970                     IODEF Version 2               November 2016   URL      Zero or more.  URL.  A URL reference to a log or audit data.   FileData      Zero or one.  The files involved in the incident.  SeeSection 3.25.   WindowsRegistryKeysModified      Zero or more.  The registry keys that were involved in the      incident.  SeeSection 3.23.   CertificateData      Zero or more.  The certificates that were involved in the      incident.  SeeSection 3.24.   AdditionalData      Zero or more.  EXTENSION.  An extension mechanism for data not      explicitly represented in the data model.   At least one of the following classes MUST be present: RecordItem,   URL, FileData, WindowsRegistryKeysModified, CertificateData, or   AdditionalData.   The attributes of the RecordData class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.22.2.  RecordPattern Class   The RecordPattern class describes where in the log data provided or   referenced in the RecordData class relevant information can be found.   It provides a way to reference subsets of information, identified by   a pattern, in a large log file, audit trail, or forensic data.Danyliw                      Standards Track                   [Page 85]

RFC 7970                     IODEF Version 2               November 2016   +-----------------------+   | RecordPattern         |   +-----------------------+   | STRING                |   |                       |   | ENUM type             |   | STRING ext-type       |   | INTEGER offset        |   | ENUM offsetunit       |   | STRING ext-offsetunit |   | INTEGER instance      |   +-----------------------+                    Figure 47: The RecordPattern Class   The content of the class is of type STRING and specifies a search   pattern.   The attributes of the RecordPattern class are:   type      Required.  ENUM.  Describes the type of pattern being specified in      the element content.  The default is "regex".  These values are      maintained in the "RecordPattern-type" IANA registry perSection 10.2.      1.  regex.  Regular expression as defined by POSIX Extended          Regular Expressions (ERE) in Chapter 9 of [IEEE.POSIX].      2.  binary.  Binhex-encoded binary pattern, per the HEXBIN data          type.      3.  xpath.  XML Path (XPath) [W3C.XPATH].      4.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.   offset      Optional.  INTEGER.  Amount of units (determined by the offsetunit      attribute) to seek into the RecordItem data before matching the      pattern.Danyliw                      Standards Track                   [Page 86]

RFC 7970                     IODEF Version 2               November 2016   offsetunit      Optional.  ENUM.  Describes the units of the offset attribute.      The default is "line".  These values are maintained in the      "RecordPattern-offsetunit" IANA registry perSection 10.2.      1.  line.  Offset is a count of lines.      2.  byte.  Offset is a count of bytes.      3.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-offsetunit      Optional.  STRING.  A means by which to extend the offsetunit      attribute.  SeeSection 5.1.1.   instance      Optional.  INTEGER.  Number of times to apply the specified      pattern.3.23.  WindowsRegistryKeysModified Class   The WindowsRegistryKeysModified class describes Windows operating   system registry keys and the operations that were performed on them.   This class was derived from [RFC5901].   +-----------------------------+   | WindowsRegistryKeysModified |   +-----------------------------+   | ID observable-id            |<>--{1..*}--[ Key ]   +-----------------------------+             Figure 48: The WindowsRegistryKeysModified Class   The aggregate classes of the WindowsRegistryKeysModified class are:   Key      One or more.  The Windows registry key.  SeeSection 3.23.1.   The attribute of the WindowsRegistryKeysModified class is:   observable-id      Optional.  ID.  SeeSection 3.3.2.Danyliw                      Standards Track                   [Page 87]

RFC 7970                     IODEF Version 2               November 20163.23.1.  Key Class   The Key class describes a Windows operating system registry key name   and value pair, as well as the operation performed on it.   +---------------------------+   | Key                       |   +---------------------------+   | ENUM registryaction       |<>----------[ KeyName  ]   | STRING ext-registryaction |<>--{0..1}--[ KeyValue ]   | ID observable-id          |   +---------------------------+                         Figure 49: The Key Class   The aggregate classes of the Key class are:   KeyName      One.  STRING.  The name of a Windows operating system registry key      (e.g., [HKEY_LOCAL_MACHINE\Software\Test\KeyName]).   KeyValue      Zero or one.  STRING.  The value of the registry key identified in      the KeyName class encoded per the .reg file format [KB310516].   The attributes of the Key class are:   registryaction      Optional.  ENUM.  The type of action taken on the registry key.      These values are maintained in the "Key-registryaction" IANA      registry perSection 10.2.      1.  add-key.  Registry key added.      2.  add-value.  Value added to a registry key.      3.  delete-key.  Registry key deleted.      4.  delete-value.  Value deleted from a registry key.      5.  modify-key.  Registry key modified.      6.  modify-value.  Value modified in a registry key.      7.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                   [Page 88]

RFC 7970                     IODEF Version 2               November 2016   ext-registryaction      Optional.  STRING.  A means by which to extend the registryaction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.24.  CertificateData Class   The CertificateData class describes X.509 certificates.   +------------------------+   | CertificateData        |   +------------------------+   | ENUM restriction       |<>--{1..*}--[ Certificate    ]   | STRING ext-restriction |   | ID observable-id       |   +------------------------+                   Figure 50: The CertificateData Class   The aggregate classes of the CertificateData class are:   Certificate      One or more.  A description of an X.509 certificate or certificate      chain.  SeeSection 3.24.1.   The attributes of the CertificateData class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.Danyliw                      Standards Track                   [Page 89]

RFC 7970                     IODEF Version 2               November 20163.24.1.  Certificate Class   The Certificate class describes a given X.509 certificate or   certificate chain.   +--------------------------+   | Certificate              |   +--------------------------+   | ID observable-id         |<>----------[ ds:X509Data    ]   |                          |<>--{0..*}--[ Description    ]   +--------------------------+                     Figure 51: The Certificate Class   The aggregate classes of the Certificate class are:   ds:X509Data      One.  A given X.509 certificate or chain.  See Section 4.4.4 of      [W3C.XMLSIG].   Description      Zero or more.  ML_STRING.  A free-form text description explaining      the context of this certificate.   The attributes of the Certificate class are:   observable-id      Optional.  ID.  SeeSection 3.3.2.3.25.  FileData Class   The FileData class describes a file or set of files.   +------------------------+   | FileData               |   +------------------------+   | ENUM restriction       |<>--{1..*}--[ File      ]   | STRING ext-restriction |   | ID observable-id       |   +------------------------+                       Figure 52: The FileData Class   The aggregate classes of the FileData class are:   File      One or more.  A description of a file.  SeeSection 3.25.1.Danyliw                      Standards Track                   [Page 90]

RFC 7970                     IODEF Version 2               November 2016   The attributes of the FileData class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.   observable-id      Optional.  ID.  SeeSection 3.3.2.3.25.1.  File Class   The File class describes a file; its associated metadata; and   cryptographic hashes and signatures applied to it.   +-----------------------+   | File                  |   +-----------------------+   | ID observable-id      |<>--{0..1}--[ FileName           ]   |                       |<>--{0..1}--[ FileSize           ]   |                       |<>--{0..1}--[ FileType           ]   |                       |<>--{0..*}--[ URL                ]   |                       |<>--{0..1}--[ HashData           ]   |                       |<>--{0..1}--[ SignatureData      ]   |                       |<>--{0..1}--[ AssociatedSoftware ]   |                       |<>--{0..*}--[ FileProperties     ]   +-----------------------+                         Figure 53: The File Class   The aggregate classes of the File class are:   FileName      Zero or one.  STRING.  The name of the file.   FileSize      Zero or one.  INTEGER.  The size of the file in bytes.   FileType      Zero or one.  STRING.  The type of file per the IANA "Media Types"      registry [IANA.Media].  Valid values correspond to the text in the      "Template" column (e.g., "application/pdf").   URL      Zero or more.  URL.  A URL reference to the file.Danyliw                      Standards Track                   [Page 91]

RFC 7970                     IODEF Version 2               November 2016   HashData      Zero or one.  Hash(es) associated with this file.  SeeSection 3.26.   SignatureData      Zero or one.  Signature(s) associated with this file.  SeeSection 3.27.   AssociatedSoftware      Zero or one.  SOFTWARE.  The software application or operating      system to which this file belongs or by which it can be processed.   FileProperties      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model to describe properties of the file.   The attributes of the File class are:   observable-id      Optional.  ID.  SeeSection 3.3.2.3.26.  HashData Class   The HashData class describes different types of hashes on a given   object (e.g., file, part of a file, email).   +--------------------------+   | HashData                 |   +--------------------------+   | ENUM scope               |<>--{0..1}--[ HashTargetID ]   |                          |<>--{0..*}--[ Hash         ]   |                          |<>--{0..*}--[ FuzzyHash    ]   +--------------------------+                       Figure 54: The HashData Class   The aggregate classes of the HashData class are:   HashTargetID      Zero or one.  STRING.  An identifier that references a subset of      the object being hashed.  The semantics of this identifier are      specified by the scope attribute.   Hash      Zero or more.  The hash of an object.  SeeSection 3.26.1.   FuzzyHash      Zero or more.  The fuzzy hash of an object.  SeeSection 3.26.2.Danyliw                      Standards Track                   [Page 92]

RFC 7970                     IODEF Version 2               November 2016   At least one instance of either Hash or FuzzyHash MUST be present.   The attribute of the HashData class is:   scope      Required.  ENUM.  Describes on which part of the object the hash      should be applied.  These values are maintained in the "HashData-      scope" IANA registry perSection 10.2.      1.  file-contents.  A hash computed over the entire contents of a          file.      2.  file-pe-section.  A hash computed on a given section of a          Windows Portable Executable (PE) file.  If set to this value,          the HashTargetID class MUST identify the section being hashed.          A section is identified by an ordinal number (starting at 1)          corresponding to the order in which the given section header          was defined in the Section Table of the PE file header.      3.  file-pe-iat.  A hash computed on the Import Address          Table (IAT) of a PE file.  As IAT hashes are often tool          dependent, if this value is set, the Application class of          either the Hash or FuzzyHash classes MUST specify the tool          used to generate the hash.      4.  file-pe-resource.  A hash computed on a given resource in a PE          file.  If set to this value, the HashTargetID class MUST          identify the resource being hashed.  A resource is identified          by an ordinal number (starting at 1) corresponding to the          order in which the given resource is declared in the Resource          Directory of the Data Dictionary in the PE file header.      5.  file-pdf-object.  A hash computed on a given object in a          Portable Document Format (PDF) file.  If set to this value,          the HashTargetID class MUST identify the object being hashed.          This object is identified by its offset in the PDF file.      6.  email-hash.  A hash computed over the headers and body of an          email message.      7.  email-headers-hash.  A hash computed over all of the headers          of an email message.      8.  email-body-hash.  A hash computed over the body of an email          message.Danyliw                      Standards Track                   [Page 93]

RFC 7970                     IODEF Version 2               November 2016      9.  ext-value.  A value used to indicate that this attribute is          extended and the actual value is provided using the          corresponding ext-* attribute.  SeeSection 5.1.1.   ext-scope      Optional.  STRING.  A means by which to extend the scope      attribute.  SeeSection 5.1.1.3.26.1.  Hash Class   The Hash class describes a cryptographic hash value; the algorithm   and application used to generate it; and the canonicalization method   applied to the object being hashed.   +----------------+   | Hash           |   +----------------+   |                |<>----------[ ds:DigestMethod            ]   |                |<>----------[ ds:DigestValue             ]   |                |<>--{0..1}--[ ds:CanonicalizationMethod  ]   |                |<>--{0..1}--[ Application                ]   +----------------+                         Figure 55: The Hash Class   The aggregate classes of the Hash class are:   ds:DigestMethod      One.  The hash algorithm used to generate the hash.  See      Section 4.3.3.5 of [W3C.XMLSIG].   ds:DigestValue      One.  The computed hash value.  See Section 4.3.3.6 of      [W3C.XMLSIG].   ds:CanonicalizationMethod      Zero or one.  The canonicalization method used on the object being      hashed.  See Section 4.3.1 of [W3C.XMLSIG].   Application      Zero or one.  SOFTWARE.  The application used to calculate the      hash.   The HashData class has no attributes.Danyliw                      Standards Track                   [Page 94]

RFC 7970                     IODEF Version 2               November 20163.26.2.  FuzzyHash Class   The FuzzyHash class describes a fuzzy hash and the application used   to generate it.   +--------------------------+   | FuzzyHash                |   +--------------------------+   |                          |<>--{1..*}--[ FuzzyHashValue ]   |                          |<>--{0..1}--[ Application    ]   |                          |<>--{0..*}--[ AdditionalData ]   +--------------------------+                      Figure 56: The FuzzyHash Class   The aggregate classes of the FuzzyHash class are:   FuzzyHashValue      One or more.  EXTENSION.  The computed fuzzy hash value.   Application      Zero or one.  SOFTWARE.  The application used to calculate the      hash.   AdditionalData      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model.   The FuzzyData class has no attributes.3.27.  SignatureData Class   The SignatureData class describes different types of digital   signatures on an object.   +--------------------------+   | SignatureData            |   +--------------------------+   |                          |<>--{1..*}--[ ds:Signature ]   +--------------------------+                    Figure 57: The SignatureData ClassDanyliw                      Standards Track                   [Page 95]

RFC 7970                     IODEF Version 2               November 2016   The aggregate class of the SignatureData class is:   Signature      One or more.  A given signature.  See Section 4.2 of [W3C.XMLSIG].   The SignatureData class has no attributes.3.28.  IndicatorData Class   The IndicatorData class describes indicators and metadata associated   with them.   +--------------------------+   | IndicatorData            |   +--------------------------+   |                          |<>--{1..*}--[ Indicator      ]   +--------------------------+                    Figure 58: The IndicatorData Class   The aggregate class of the IndicatorData class is:   Indicator      One or more.  A description of an indicator.  SeeSection 3.29.   The IndicatorData class has no attributes.3.29.  Indicator Class   The Indicator class describes an indicator.  An indicator consists of   observable features and phenomenon that aid in the forensic or   proactive detection of malicious activity and associated metadata.   An indicator can be described outright by referencing or composing   previously defined indicators or by referencing observables described   in the incident report found in this document.Danyliw                      Standards Track                   [Page 96]

RFC 7970                     IODEF Version 2               November 2016   +------------------------+   | Indicator              |   +------------------------+   | ENUM restriction       |<>----------[ IndicatorID            ]   | STRING ext-restriction |<>--{0..*}--[ AlternativeIndicatorID ]   |                        |<>--{0..*}--[ Description            ]   |                        |<>--{0..1}--[ StartTime              ]   |                        |<>--{0..1}--[ EndTime                ]   |                        |<>--{0..1}--[ Confidence             ]   |                        |<>--{0..*}--[ Contact                ]   |                        |<>--{0..1}--[ Observable             ]   |                        |<>--{0..1}--[ ObservableReference    ]   |                        |<>--{0..1}--[ IndicatorExpression    ]   |                        |<>--{0..1}--[ IndicatorReference     ]   |                        |<>--{0..*}--[ NodeRole               ]   |                        |<>--{0..*}--[ AttackPhase            ]   |                        |<>--{0..*}--[ Reference              ]   |                        |<>--{0..*}--[ AdditionalData         ]   +------------------------+                      Figure 59: The Indicator Class   The aggregate classes of the Indicator class are:   IndicatorID      One.  An identifier for this indicator.  SeeSection 3.29.1.   AlternativeIndicatorID      Zero or more.  An alternative identifier for this indicator.  SeeSection 3.29.2.   Description      Zero or more.  ML_STRING.  A free-form text description of the      indicator.   StartTime      Zero or one.  DATETIME.  A timestamp of the start of the time      period during which this indicator is valid.   EndTime      Zero or one.  DATETIME.  A timestamp of the end of the time period      during which this indicator is valid.   Confidence      Zero or one.  An estimate of the confidence in the quality of the      indicator.  SeeSection 3.12.5.Danyliw                      Standards Track                   [Page 97]

RFC 7970                     IODEF Version 2               November 2016   Contact      Zero or more.  Contact information for this indicator.  SeeSection 3.9.   Observable      Zero or one.  An observable feature or phenomenon of this      indicator.  SeeSection 3.29.3.   ObservableReference      Zero or one.  A reference to an observable feature or phenomenon      defined elsewhere in the document.  SeeSection 3.29.6.   IndicatorExpression      Zero or one.  A composition of observables.  SeeSection 3.29.4.   IndicatorReference      Zero or one.  A reference to an indicator.  SeeSection 3.29.7.   NodeRole      Zero or more.  The role of the system in the attack should this      indicator be matched to it.  SeeSection 3.18.2.   AttackPhase      Zero or more.  The phase in an attack life cycle during which this      indicator might be seen.  SeeSection 3.29.8.   Reference      Zero or more.  A reference to additional information relevant to      this indicator.  SeeSection 3.11.1.   AdditionalData      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model.   The Indicator class MUST have exactly one instance of an Observable,   IndicatorExpression, ObservableReference, or IndicatorReference   class.   The StartTime and EndTime classes can be used to define an interval   during which the indicator is valid.  If both classes are present,   the indicator is consider valid only during the described interval.   If neither class is provided, the indicator is considered valid   during any time interval.  If only a StartTime is provided, the   indicator is valid anytime after this timestamp.  If only an EndTime   is provided, the indicator is valid anytime prior to this timestamp.Danyliw                      Standards Track                   [Page 98]

RFC 7970                     IODEF Version 2               November 2016   The attributes of the Indicator class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.29.1.  IndicatorID Class   The IndicatorID class identifies an indicator with a globally unique   identifier.  The combination of the name and version attributes and   the element content form this identifier.  Indicators generated by   given CSIRT MUST NOT reuse the same value unless they are referencing   the same indicator.   +------------------+   | IndicatorID      |   +------------------+   | ID               |   |                  |   | STRING name      |   | STRING version   |   +------------------+                     Figure 60: The IndicatorID Class   The content of the class is of type ID and specifies an identifier   for an indicator.   The attributes of the IndicatorID class are:   name      Required.  STRING.  An identifier describing the CSIRT that      created the indicator.  In order to have a globally unique CSIRT      name, the fully qualified domain name associated with the CSIRT      MUST be used.  This format is identical to the IncidentID@name      attribute inSection 3.4.   version      Required.  STRING.  A version number of an indicator.Danyliw                      Standards Track                   [Page 99]

RFC 7970                     IODEF Version 2               November 20163.29.2.  AlternativeIndicatorID Class   The AlternativeIndicatorID class lists alternative identifiers for an   indicator.   +-------------------------+   | AlternativeIndicatorID  |   +-------------------------+   | ENUM restriction        |<>--{1..*}--[ IndicatorReference ]   | STRING ext-restriction  |   +-------------------------+                Figure 61: The AlternativeIndicatorID Class   The aggregate class of the AlternativeIndicatorID class is:   IndicatorReference      One or more.  A reference to an indicator.  SeeSection 3.29.7.   The attributes of the AlternativeIndicatorID class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.Danyliw                      Standards Track                  [Page 100]

RFC 7970                     IODEF Version 2               November 20163.29.3.  Observable Class   The Observable class describes a feature and phenomenon that can be   observed or measured for the purposes of detecting malicious   behavior.   +------------------------+   | Observable             |   +------------------------+   | ENUM restriction       |<>--{0..1}--[ System                      ]   | STRING ext-restriction |<>--{0..1}--[ Address                     ]   |                        |<>--{0..1}--[ DomainData                  ]   |                        |<>--{0..1}--[ Service                     ]   |                        |<>--{0..1}--[ EmailData                   ]   |                        |<>--{0..1}--[ WindowsRegistryKeysModified ]   |                        |<>--{0..1}--[ FileData                    ]   |                        |<>--{0..1}--[ CertificateData             ]   |                        |<>--{0..1]--[ RegistryHandle              ]   |                        |<>--{0..1}--[ RecordData                  ]   |                        |<>--{0..1}--[ EventData                   ]   |                        |<>--{0..1}--[ Incident                    ]   |                        |<>--{0..1}--[ Expectation                 ]   |                        |<>--{0..1}--[ Reference                   ]   |                        |<>--{0..1}--[ Assessment                  ]   |                        |<>--{0..1}--[ DetectionPattern            ]   |                        |<>--{0..1}--[ HistoryItem                 ]   |                        |<>--{0..1}--[ BulkObservable              ]   |                        |<>--{0..*}--[ AdditionalData              ]   +------------------------+                      Figure 62: The Observable Class   The aggregate classes of the Observable class are:   System      Zero or one.  A System observable.  SeeSection 3.17.   Address      Zero or one.  An Address observable.  SeeSection 3.18.1.   DomainData      Zero or one.  A DomainData observable.  SeeSection 3.19.   Service      Zero or one.  A Service observable.  SeeSection 3.20.   EmailData      Zero or one.  An EmailData observable.  SeeSection 3.21.Danyliw                      Standards Track                  [Page 101]

RFC 7970                     IODEF Version 2               November 2016   WindowsRegistryKeysModified      Zero or one.  A WindowsRegistryKeysModified observable.  SeeSection 3.23.   FileData      Zero or one.  A FileData observable.  SeeSection 3.25.   CertificateData      Zero or one.  A CertificateData observable.  SeeSection 3.24.   RegistryHandle      Zero or one.  A RegistryHandle observable.  SeeSection 3.9.1.   RecordData      Zero or one.  A RecordData observable.  SeeSection 3.22.1.   EventData      Zero or one.  An EventData observable.  SeeSection 3.14.   Incident      Zero or one.  An Incident observable.  SeeSection 3.2.   Expectation      Zero or one.  An Expectation observable.  SeeSection 3.15.   Reference      Zero or one.  A Reference observable.  SeeSection 3.11.1.   Assessment      Zero or one.  An Assessment observable.  SeeSection 3.12.   DetectionPattern      Zero or one.  A DetectionPattern observable.  SeeSection 3.10.1.   HistoryItem      Zero or one.  A HistoryItem observable.  SeeSection 3.13.1.   BulkObservable      Zero or one.  A bulk list of observables.  SeeSection 3.29.3.1.   AdditionalData      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model.   The Observable class MUST have exactly one of the possible child   classes.Danyliw                      Standards Track                  [Page 102]

RFC 7970                     IODEF Version 2               November 2016   The attributes of the Observable class are:   restriction      Optional.  ENUM.  SeeSection 3.3.1.   ext-restriction      Optional.  STRING.  A means by which to extend the restriction      attribute.  SeeSection 5.1.1.3.29.3.1.  BulkObservable Class   The BulkObservable class allows the enumeration of a single type of   observable without requiring each one to be encoded individually in   multiple instances of the same class.   The type attribute describes the type of observable listed in the   child BulkObservableList class.  The BulkObservableFormat class   optionally provides additional metadata.   +---------------------------+   | BulkObservable            |   +---------------------------+   | ENUM type                 |<>--{0..1}--[ BulkObservableFormat ]   | STRING ext-type           |<>----------[ BulkObservableList   ]   |                           |<>--{0..*}--[ AdditionalData       ]   +---------------------------+                    Figure 63: The BulkObservable Class   The aggregate classes of the BulkObservable class are:   BulkObservableFormat      Zero or one.  Provides additional metadata about the observables      enumerated in the BulkObservableList class.  SeeSection 3.29.3.1.1.   BulkObservableList      One.  STRING.  A list of observables, one per line.  Each line is      separated with either a LF character or CR and LF characters.  The      type attribute specifies which observables will be listed.   AdditionalData      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model.Danyliw                      Standards Track                  [Page 103]

RFC 7970                     IODEF Version 2               November 2016   The attributes of the BulkObservable class are:   type      Optional.  ENUM.  The type of the observable listed in the child      ObservableList class.  These values are maintained in the      "BulkObservable-type" IANA registry perSection 10.2.      1.   asn.  Autonomous System Number (per the Address@category           attribute).      2.   atm.  Asynchronous Transfer Mode (ATM) address (per the           Address@category attribute).      3.   e-mail.  Email address (per the Address@category attribute).      4.   ipv4-addr.  IPv4 host address in dotted-decimal notation,           e.g., 192.0.2.1 (per the Address@category attribute).      5.   ipv4-net.  IPv4 network address in dotted-decimal notation,           slash, significant bits, e.g., 192.0.2.0/24 (per the           Address@category attribute).      6.   ipv4-net-mask.  IPv4 network address in dotted-decimal           notation, slash, network mask in dotted-decimal notation,           i.e., 192.0.2.0/255.255.255.0 (per the Address@category           attribute).      7.   ipv6-addr.  IPv6 host address, e.g., 2001:DB8::3 (per the           Address@category attribute).      8.   ipv6-net.  IPv6 network address, slash, significant bits,           e.g., 2001:DB8::/32 (per the Address@category attribute).      9.   ipv6-net-mask.  IPv6 network address, slash, network mask           (per the Address@category attribute).      10.  mac.  Media Access Control (MAC) address, i.e., a:b:c:d:e:f           (per the Address@category attribute).      11.  site-uri.  A URL or URI for a resource (per the           Address@category attribute).      12.  domain-name.  A fully qualified domain name or part of a name           (e.g., fqdn.example.com, example.com).      13.  domain-to-ipv4.  A mapping of FQDN to IPv4 address specified           as a comma-separated list (e.g., "fqdn.example.com,           192.0.2.1").Danyliw                      Standards Track                  [Page 104]

RFC 7970                     IODEF Version 2               November 2016      14.  domain-to-ipv6.  A mapping of FQDN to IPv6 address specified           as a comma-separated list (e.g., "fqdn.example.com,           2001:DB8::3").      15.  domain-to-ipv4-timestamp.  Same as domain-to-ipv4 but with a           timestamp (in the DATETIME format) of the resolution (e.g.,           "fqdn.example.com, 192.0.2.1, 2015-06-11T00:38:31-06:00").      16.  domain-to-ipv6-timestamp.  Same as domain-to-ipv6 but with a           timestamp (in the DATETIME format) of the resolution (e.g.,           "fqdn.example.com, 2001:DB8::3, 2015-06-11T00:38:31-06:00").      17.  ipv4-port.  An IPv4 address, port, and protocol tuple (e.g.,           192.0.2.1, 80, TCP).  The protocol name corresponds to the           "Keyword" column in the "Assigned Internet Protocol Numbers"           registry [IANA.Protocols].      18.  ipv6-port.  An IPv6 address, port, and protocol tuple (e.g.,           2001:DB8::3, 80, TCP).  The protocol name corresponds to the           "Keyword" column in the "Assigned Internet Protocol Numbers"           registry [IANA.Protocols].      19.  windows-reg-key.  A Microsoft Windows registry key.      20.  file-hash.  A file hash.  The format of this hash is           described in the Hash class that MUST be present in a sibling           BulkObservableFormat class.      21.  email-x-mailer.  An X-Mailer field from an email.      22.  email-subject.  An email subject line.      23.  http-user-agent.  A User Agent field from an HTTP request           header (e.g., "Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0)           Gecko/20100101 Firefox/38.0").      24.  http-request-uri.  The Request URI from an HTTP request           header.      25.  mutex.  The name of a system mutex (mutual exclusion lock).      26.  file-path.  A file path (e.g., "/tmp/local/file",           "c:\windows\system32\file.sys").      27.  user-name.  A username.Danyliw                      Standards Track                  [Page 105]

RFC 7970                     IODEF Version 2               November 2016      28.  ext-value.  A value used to indicate that this attribute is           extended and the actual value is provided using the           corresponding ext-* attribute.  SeeSection 5.1.1.   ext-type      Optional.  STRING.  A means by which to extend the type attribute.      SeeSection 5.1.1.3.29.3.1.1.  BulkObservableFormat Class   The ObservableFormat class specifies metadata about the format of an   observable enumerated in a sibling BulkObservableList class.   +---------------------------+   | BulkObservableFormat      |   +---------------------------+   |                           |<>--{0..1}--[ Hash             ]   |                           |<>--{0..*}--[ AdditionalData   ]   +---------------------------+                 Figure 64: The BulkObservableFormat Class   The aggregate classes of the BulkObservableFormat class are:   Hash      Zero or one.  Describes the format of a hash.  SeeSection 3.26.1.   AdditionalData      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model.   The BulkObservableFormat class has no attributes.   Either Hash or AdditionalData MUST be present.3.29.4.  IndicatorExpression Class   The IndicatorExpression describes an expression composed of observed   phenomenon, features, or indicators.  Elements of the expression can   be described directly, reference relevant data from other parts of a   given IODEF document, or reference previously defined indicators.   All child classes of a given instance of IndicatorExpression form a   boolean algebraic expression where the operator between them is   determined by the operator attribute.Danyliw                      Standards Track                  [Page 106]

RFC 7970                     IODEF Version 2               November 2016   +--------------------------+   | IndicatorExpression      |   +--------------------------+   | ENUM operator            |<>--{0..*}--[ IndicatorExpression  ]   | STRING ext-operator      |<>--{0..*}--[ Observable           ]   |                          |<>--{0..*}--[ ObservableReference  ]   |                          |<>--{0..*}--[ IndicatorReference   ]   |                          |<>--{0..1}--[ Confidence           ]   |                          |<>--{0..*}--[ AdditionalData       ]   +--------------------------+                 Figure 65: The IndicatorExpression Class   The aggregate classes of the IndicatorExpression class are:   IndicatorExpression      Zero or more.  An expression composed of other observables or      indicators.  SeeSection 3.29.4.   Observable      Zero or more.  A description of an observable.  SeeSection 3.29.3.   ObservableReference      Zero or more.  A reference to an observable.  SeeSection 3.29.6.   IndicatorReference      Zero or more.  A reference to an indicator.  SeeSection 3.29.7.   Confidence      Zero or one.  An estimate of the confidence in the quality of the      terms expressed in the expression.  SeeSection 3.12.5.   AdditionalData      Zero or more.  EXTENSION.  Mechanism by which to extend the data      model.   The attributes of the IndicatorExpression class are:   operator      Optional.  ENUM.  The operator to be applied between the child      elements.  SeeSection 3.29.5 for parsing guidance.  The default      value is "and".  These values are maintained in the      "IndicatorExpression-operator" IANA registry perSection 10.2.      1.  not.  negation operator.      2.  and.  conjunction operator.Danyliw                      Standards Track                  [Page 107]

RFC 7970                     IODEF Version 2               November 2016      3.  or.  disjunction operator.      4.  xor.  exclusive disjunction operator.   ext-operator      Optional.  STRING.  A means by which to extend the operator      attribute.  SeeSection 5.1.1.3.29.5.  Expressions with IndicatorExpression   Boolean algebraic expressions can be used to specify relationships   between observables and indicators.  These expressions are   constructed through the use of the operator attribute and parent-   child relationships in IndicatorExpressions.  These expressions   should be parsed as follows:   1.  The operator specified by the operator attribute is applied       between each of the child elements of the immediate parent       IndicatorExpression element.  If no operator attribute is       specified, it should be assumed to be the conjunction operator       (i.e., operator="and").   2.  A nested IndicatorExpression element with a parent       IndicatorExpression is the equivalent of a parentheses in the       expression.   The following examples in Figures 66 through 70 illustrate these   parsing rules:   1     : <IndicatorExpression>   2 [O1]:    <Observable>..</Observable>   3 [O2]:    <Observable>..</Observable>   4     : </IndicatorExpression>   Equivalent expression: (O1 AND O2)      Figure 66: Nested Elements in an IndicatorExpression without an                       Operator Attribute Specified   1     : <IndicatorExpression operator="or">   2 [O1]:    <Observable>..</Observable>   3 [O2]:    <Observable>..</Observable>   4     : </IndicatorExpression>   Equivalent expression: (O1 OR O2)   Figure 67: Nested Elements in an IndicatorExpression with an Operator                            Attribute SpecifiedDanyliw                      Standards Track                  [Page 108]

RFC 7970                     IODEF Version 2               November 2016   1     : <IndicatorExpression operator="or">   2     :    <IndicatorExpression operator="or">   3 [O1]:      <Observable>..</Observable>   4 [O2]:      <Observable>..</Observable>   5     :    </IndicatorExpression>   6 [O3]:    <Observable>..</Observable>   7     : </IndicatorExpression>   Equivalent expression: ((O1 OR O2) OR O3)   Figure 68: Nested Elements with a Recursive IndicatorExpression with                      an Operator Attribute Specified   1     : <IndicatorExpression operator="not">   2     :    <IndicatorExpression operator="and">   3 [O1]:      <Observable>..</Observable>   4 [O2]:      <Observable>..</Observable>   5     :    </IndicatorExpression>   6     : </IndicatorExpression>   Equivalent expression: (NOT (O1 AND O2))   Figure 69: A Recursive IndicatorExpression with an Operator Attribute                                 Specified    1                          :    <IndicatorExpression operator="or">    2                          :      <IndicatorExpression>    3 [O1 with low confidence] :        <Observable>..</Observable>    4                          :        <Confidence rating="low" />    5                          :      </IndicatorExpression>    6                          :      <IndicatorExpression>    7 [O2 with high confidence]:        <Observable>..</Observable>    8                          :        <Confidence rating="high" />    9                          :      </IndicatorExpression>   10                          :    </IndicatorExpression>   Equivalent expression: ((O1) OR (O2))          Figure 70: Varying Confidence on Particular Observables   Invalid algebraic expressions while valid XML MUST NOT be specified.Danyliw                      Standards Track                  [Page 109]

RFC 7970                     IODEF Version 2               November 20163.29.6.  ObservableReference Class   The ObservableReference describes a reference to an observable   feature or phenomenon described elsewhere in the document.   The ObservableReference class has no content.   +-------------------------+   | ObservableReference     |   +-------------------------+   | IDREF uid-ref           |   +-------------------------+                 Figure 71: The ObservableReference Class   The ObservableReference class has no content.   The attribute of the ObservableReference class is:   uid-ref      Required.  IDREF.  An identifier that serves as a reference to a      class in the IODEF document.  The referenced class will have this      identifier set in its observable-id attribute.3.29.7.  IndicatorReference Class   The IndicatorReference describes a reference to an indicator.  This   reference may be to an indicator described in this IODEF document or   in a previously exchanged IODEF document.   The IndicatorReference class has no content.   +--------------------------+   | IndicatorReference       |   +--------------------------+   | IDREF uid-ref            |   | STRING euid-ref          |   | STRING version           |   +--------------------------+                  Figure 72: The IndicatorReference Class   The attributes of the IndicatorReference class are:   uid-ref      Optional.  IDREF.  An identifier that references an Indicator      class in the IODEF document.  The referenced Indicator class will      have this identifier set in its IndicatorID class.Danyliw                      Standards Track                  [Page 110]

RFC 7970                     IODEF Version 2               November 2016   euid-ref      Optional.  STRING.  An identifier that references an IndicatorID      not in this IODEF document.   version      Optional.  STRING.  A version number of an indicator.   Either the uid-ref or the euid-ref attribute MUST be set.3.29.8.  AttackPhase Class   The AttackPhase class describes a particular phase of an attack life   cycle.   +------------------------+   | AttackPhase            |   +------------------------+   |                        |<>--{0..*}--[ AttackPhaseID  ]   |                        |<>--{0..*}--[ URL            ]   |                        |<>--{0..*}--[ Description    ]   |                        |<>--{0..*}--[ AdditionalData ]   +------------------------+                     Figure 73: The AttackPhase Class   The aggregate classes of the AttackPhase class are:   AttackPhaseID      Zero or more.  STRING.  An identifier for the phase of the attack.   URL      Zero or more.  URL.  A URL to a resource describing this phase of      the attack.   Description      Zero or more.  ML_STRING.  A free-form text description of this      phase of the attack.   AdditionalData      Zero or more.  EXTENSION.  A mechanism by which to extend the data      model.   AttackPhase MUST have at least one instance of a child class.   The AttackPhase class has no attributes.Danyliw                      Standards Track                  [Page 111]

RFC 7970                     IODEF Version 2               November 20164.  Processing Considerations   This section provides additional requirements and guidance on   creating and processing IODEF documents.4.1.  Encoding   Every IODEF document MUST begin with an XML declaration and MUST   specify the XML version used.  The character encoding MUST also be   explicitly specified.  UTF-8 [RFC3629] SHOULD be used unless UTF-16   [RFC2781] is necessary.  Encodings other than UTF-8 and UTF-16 SHOULD   NOT be used.  The IODEF conforms to all XML data-encoding conventions   and constraints.   The XML declaration with UTF-8 character encoding will read as   follows:   <?xml version="1.0" encoding="UTF-8" ?>   Certain characters have special meaning in XML and MUST not appear in   literal form.  Per Section 2.4 of [W3C.XML], these characters MUST be   escaped with a numeric character or entity reference.4.2.  IODEF Namespace   The IODEF schema declares a namespace of   "urn:ietf:params:xml:ns:iodef-2.0" and registers it per [W3C.XMLNS].   Each IODEF document MUST include a valid reference to the IODEF   schema using the "xsi:schemaLocation" attribute.  An example of such   a declaration would look as follows:   <IODEF-Document      version="2.00" lang="en-US"      xmlns:iodef="urn:ietf:params:xml:ns:iodef-2.0"      xsi:schemaLocation="urn:ietf:params:xmls:schema:iodef-2.0" ...>4.3.  Validation   IODEF documents MUST be well-formed XML.  It is RECOMMENDED that   recipients validate the document against the schema described inSection 8.  However, mere conformance to this schema is not   sufficient for a semantically valid IODEF document.  The text ofSection 3 describes further formatting and constraints, including   some that cannot be conveniently encoded in the schema.  These MUST   also be considered by an IODEF implementation.  Furthermore, the   enumerated values present in this document are a static list that   will be incomplete over time as select attributes can be extended by   a corresponding IANA registry perSection 10.2.  Therefore, IODEFDanyliw                      Standards Track                  [Page 112]

RFC 7970                     IODEF Version 2               November 2016   implementations SHOULD periodically update their schema and MAY need   to update their parsing algorithms to incorporate newly registered   values.4.4.  Incompatibilities with v1   The IODEF data model in this document makes a number of changes to   [RFC5070].  These changes were largely additive -- classes and   enumerated values were added.  However, some incompatibilities   between [RFC5070] and this new specification were introduced.  These   incompatibilities are as follows:   o  The IODEF-Document@version attribute is set to "2.0".   o  Attributes with enumerated values can now also be extended with      IANA registries.   o  All iodef:MLStringType classes use xml:lang.  IODEF-Document also      uses xml:lang.   o  The Service@ip_protocol attribute was renamed to @ip-protocol.   o  The Node/NodeName class was removed in favor of representing      domain names with Node/DomainData/Name class.  The Node/DataTime      class was also removed, so that the Node/DomainData/      DateDomainWasChecked class can represent the time at which the      name-to-address resolution occurred.   o  The Node/NodeRole class was moved to System/NodeRole.   o  The Reference class is now defined by [RFC7495].   o  The data previously represented in the Impact class is now in the      SystemImpact and IncidentCategory classes.  The Impact class has      been removed.   o  The semantics of Counter@type are now represented in Counter@unit.   o  The IODEF-Document@formatid attribute has been renamed to @format-      id.   o  The Incident/ReportTime class is no longer required.  However, the      GenerationTime class is required.   o  The Fax class was removed and is now represented by a generic      Telephone class.Danyliw                      Standards Track                  [Page 113]

RFC 7970                     IODEF Version 2               November 2016   o  The Telephone, Email, and PostalAddress classes were redefined      from improved internationalization.   o  The "ipv6-net-mask" value was removed from the category attribute      of Address.5.  Extending the IODEF   In order to support the dynamic nature of security operations, the   IODEF data model will need to continue to evolve.  This section   discusses how new data elements can be incorporated into the IODEF.   There is support to add additional enumerated values and new classes.   Adding additional attributes to existing classes is not supported.   These extension mechanisms are designed so that adding new data   elements is possible without requiring modifications to this   document.  Extensions can be implemented publicly or privately.  With   proven value, well-documented extensions can be incorporated into   future versions of the specification.5.1.  Extending the Enumerated Values of Attributes   Additional enumerated values can be added to select attributes either   through the use of specially marked attributes with the "ext-" prefix   or through a set of corresponding IANA registries.  The former   approach allows for the extension to remain private.  The latter   approach is public.5.1.1.  Private Extension of Enumerated Values   The data model supports adding new enumerated values to an attribute   without public registration.  For each attribute that supports this   extension technique, there is a corresponding attribute in the same   element whose name is identical but with a prefix of "ext-".  This   special attribute is referred to as the extension attribute.  The   attribute being extended is referred to as an extensible attribute.   For example, an extensible attribute named "foo" will have a   corresponding extension attribute named "ext-foo".  An element may   have many extensible attributes.   In addition to a corresponding extension attribute, each extensible   attribute has "ext-value" as one its possible enumerated values.   Selection of this particular value in an extensible attribute signals   that the extension attribute contains data.  Otherwise, this   "ext-value" value has no meaning.Danyliw                      Standards Track                  [Page 114]

RFC 7970                     IODEF Version 2               November 2016   In order to add a new enumerated value to an extensible attribute,   the value of this attribute MUST be set to "ext-value", and the new   desired value MUST be set in the corresponding extension attribute.   For example, extending the type attribute of the SystemImpact class   would look as follows:    <SystemImpact type="ext-value" ext-type="new-attack-type">   A given extension attribute MUST NOT be set unless the corresponding   extensible attribute has been set to "ext-value".5.1.2.  Public Extension of Enumerated Values   The data model also supports publicly extending select enumerated   attributes.  A new entry can be added by registering a new entry in   the appropriate IANA registry.Section 10.2 provides a mapping   between the extensible attributes and their corresponding registry.Section 4.3 discusses the XML validation implications of this type of   extension.  All extensible attributes that support private extensions   also support public extensions.5.2.  Extending Classes   Classes of the EXTENSION (iodef:ExtensionType) type can extend the   data model.  They provide the ability to have new atomic or XML-   encoded data elements in all of the top-level classes of the Incident   class and in a few of the complex subordinate classes.  As there are   multiple instances of the extensible classes in the data model, there   is discretion on where to add a new data element.  It is RECOMMENDED   that the extension be placed in the most closely related class to the   new information.   Extensions using the atomic data types (i.e., all values of the dtype   attributes other than "xml") MUST:   1.  Set the element content to the desired value, and   2.  Set the dtype attribute to correspond to the data type of the       element content.Danyliw                      Standards Track                  [Page 115]

RFC 7970                     IODEF Version 2               November 2016   The following guidelines exist for extensions using XML (i.e.,   dtype="xml"):   1.  The element content of the extensible class MUST be set to the       desired value, and the dtype attribute MUST be set to "xml".   2.  The extension schema MUST declare a separate namespace.  It is       RECOMMENDED that these extensions have the prefix "iodef-".  This       recommendation makes readability of the document easier by       allowing the reader to infer which namespaces relate to IODEF by       inspection.   3.  It is RECOMMENDED that extension schemas follow the naming       convention of the IODEF data model.  This too improves the       readability of extended IODEF documents.  The names of all       elements SHOULD be capitalized.  For elements with composed       names, a capital letter SHOULD be used for each word.  Attribute       names SHOULD be in lowercase.  Attributes with composed names       SHOULD be separated by a hyphen.   4.  Implementations that encounter an unrecognized element,       attribute, or attribute value in a supported namespace SHOULD       reject the document as a syntax error.   5.  There are security and performance implications in requiring       implementations to dynamically download schemas at runtime.       Therefore, implementations MUST NOT download schemas at runtime       unless the appropriate precautions are taken.  Implementations       also need to contend with the potential of significant network       and processing issues.   6.  Some adopters of the IODEF may have private schema definitions       that are not publicly available.  Thus, implementations may       encounter IODEF documents with references to private schemas that       may not be resolvable.  Hence, IODEF document recipients MUST be       prepared for a schema definition in an IODEF document never to       resolve.Danyliw                      Standards Track                  [Page 116]

RFC 7970                     IODEF Version 2               November 2016   The following schema and XML document excerpt provide a template for   an extension schema and its use in the IODEF document.   This example schema defines a namespace of "iodef-extension1" and a   single element named "newdata".     <xs:schema        targetNamespace="iodef-extension1.xsd"        xmlns:iodef-extension1="iodef-extension1.xsd"        xmlns:xs="http://www.w3.org/2001/XMLSchema">        attributeFormDefault="unqualified"        elementFormDefault="qualified">      <xs:import           namespace="urn:ietf:params:xml:ns:iodef-2.0"           schemaLocation=" urn:ietf:params:xml:schema:iodef-2.0"/>        <xs:element name="newdata" type="xs:string" />     </xs:schema>   The following XML excerpt demonstrates the use of the above schema as   an extension to the IODEF.        <IODEF-Document             version="2.00" lang="en-US"             xmlns="urn:ietf:params:xml:ns:iodef-2.0"             xmlns:iodef=" urn:ietf:params:xml:ns:iodef-2.0"             xmlns:iodef-extension1="iodef-extension1.xsd"             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"             xsi:schemaLocation="iodef-extension1.xsd">            <Incident purpose="reporting">            ...              <AdditionalData dtype="xml" meaning="xml">                <iodef-extension1:newdata>                 Field that could not be represented elsewhere                </iodef-extension1:newdata>              </AdditionalData>            </Incident>      </IODEF-Document>5.3.  Deconflicting Private Extensions   To disambiguate which private extension is used in an IODEF document,   the data model provides a means to identify the source of an   extension.  Two attributes in the IODEF-Document class,   private-enum-name and private-enum-id, are used to specify this   attribution.  Only a single private extension can be identified in a   given IODEF-Document.Danyliw                      Standards Track                  [Page 117]

RFC 7970                     IODEF Version 2               November 2016   If an implementor has a single private extension, then only the   private-enum-name attribute needs to be specified.  Multiple distinct   private extensions or versioning of a single extension can be   attributed by also setting the corresponding private-num-id   attribute.   The following XML excerpt demonstrates the specification of a private   extension from "example.com" with an identifier of "13".        <IODEF-Document             version="2.00" lang="en-US"             private-enum-name="example.com"             private-enum-id="13" ...>            ...      </IODEF-Document>   If an unrecognized private extension is encountered in processing,   the recipient MAY reject the entire document as a syntax error.6.  Internationalization Issues   Internationalization and localization is of specific concern to the   IODEF as it facilitates operational coordination with a diverse set   of partners.  The IODEF implements internationalization by relying on   XML constructs and through explicit design choices in the data model.   Since the IODEF is implemented as an XML schema, it supports   different character encodings, such as UTF-8 and UTF-16, that are   possible with XML.  Additionally, each IODEF document MUST specify   the language in which its content is encoded.  The language can be   specified with the attribute "xml:lang" (per Section 2.12 of   [W3C.XML]) in the top-level element (i.e., IODEF-Document) and lets   all other elements inherit that definition.  All IODEF classes with a   free-form text definition (i.e., all those defined with type   iodef:MLStringType) can also specify a language different from the   rest of the document.   The data model supports multiple translations of free-form text.  All   ML_STRING (iodef:MLStringType) classes have a one-to-many cardinality   to their parent.  This allows the identical text translated into   different languages to be encoded in different instances of the same   class with a common parent.  This design also enables the creation of   a single document containing all the translations.  The IODEF   implementation SHOULD extract the appropriate language relevant to   the recipient.Danyliw                      Standards Track                  [Page 118]

RFC 7970                     IODEF Version 2               November 2016   Related instances of a given iodef:MLStringType class that are   translations of each other are identified by a common identifier set   in the translation-id attribute.  The example below shows three   instances of a Description class expressed in three different   languages.  The relationship between these three instances of the   Description class is conveyed by the common value of "1" in the   translation-id attribute.   <IODEF-Document version="2.00" xml:lang="en" ...>     <Incident purpose="reporting">       ...       <Description translation-id="1"                    xml:lang="en">English</Description>       <Description translation-id="1"                    xml:lang="de">Englisch</Description>       <Description translation-id="1"                    xml:lang="fr">Anglais</Description>   The IODEF balances internationalization support with the need for   interoperability.  While the IODEF supports different languages, the   data model also relies heavily on standardized enumerated attributes   that can crudely approximate the contents of the document.  With this   approach, a CSIRT should be able to make some sense of an IODEF   document it receives even if the free-form text data elements are   written in a language unfamiliar to the recipient.7.  Examples   This section provides examples of IODEF documents.  These examples do   not represent the full capabilities of the data model or the only way   to encode particular information.7.1.  Minimal Example   A document containing only the mandatory elements and attributes.   <?xml version="1.0" encoding="UTF-8"?>   <!-- Minimum IODEF document -->   <IODEF-Document version="2.00" xml:lang="en"      xmlns="urn:ietf:params:xml:ns:iodef-2.0"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xsi:schemaLocation=   "http://www.iana.org/assignments/xml-registry/schema/iodef-2.0.xsd">     <Incident purpose="reporting" restriction="private">       <IncidentID name="csirt.example.com">492382</IncidentID>       <GenerationTime>2015-07-18T09:00:00-05:00</GenerationTime>       <Contact type="organization" role="creator">Danyliw                      Standards Track                  [Page 119]

RFC 7970                     IODEF Version 2               November 2016         <Email>           <EmailTo>contact@csirt.example.com</EmailTo>         </Email>       </Contact>       <!-- Add more fields to make the document useful -->     </Incident>   </IODEF-Document>7.2.  Indicators from a Campaign   An example of C2 domains from a given campaign.   <?xml version="1.0" encoding="UTF-8"?>   <!-- A list of C2 domains associated with a campaign -->   <IODEF-Document version="2.00" xml:lang="en"      xmlns="urn:ietf:params:xml:ns:iodef-2.0"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xsi:schemaLocation=      "http://www.iana.org/assignments/xml-registry/schema/iodef-2.0.xsd">     <Incident purpose="watch" restriction="green">       <IncidentID name="csirt.example.com">897923</IncidentID>         <RelatedActivity>           <ThreatActor>             <ThreatActorID>             TA-12-AGGRESSIVE-BUTTERFLY             </ThreatActorID>             <Description>Aggressive Butterfly</Description>           </ThreatActor>           <Campaign>             <CampaignID>C-2015-59405</CampaignID>             <Description>Orange Giraffe</Description>           </Campaign>         </RelatedActivity>         <GenerationTime>2015-10-02T11:18:00-05:00</GenerationTime>         <Description>Summarizes the Indicators of Compromise           for the Orange Giraffe campaign of the Aggressive           Butterfly crime gang.         </Description>         <Assessment>           <BusinessImpact type="breach-proprietary"/>         </Assessment>         <Contact type="organization" role="creator">           <ContactName>CSIRT for example.com</ContactName>           <Email>             <EmailTo>contact@csirt.example.com</EmailTo>           </Email>         </Contact>Danyliw                      Standards Track                  [Page 120]

RFC 7970                     IODEF Version 2               November 2016         <IndicatorData>           <Indicator>             <IndicatorID name="csirt.example.com" version="1">             G90823490             </IndicatorID>             <Description>C2 domains</Description>             <StartTime>2014-12-02T11:18:00-05:00</StartTime>             <Observable>               <BulkObservable type="fqdn">               <BulkObservableList>                 kj290023j09r34.example.com                 09ijk23jfj0k8.example.net                 klknjwfjiowjefr923.example.org                 oimireik79msd.example.org               </BulkObservableList>             </BulkObservable>           </Observable>         </Indicator>       </IndicatorData>     </Incident>   </IODEF-Document>8.  The IODEF Data Model (XML Schema)  <?xml version="1.0"?>  <xs:schema xmlns="urn:ietf:params:xml:ns:iodef-2.0"             xmlns:iodef="urn:ietf:params:xml:ns:iodef-2.0"             xmlns:enum="urn:ietf:params:xml:ns:iodef-enum-1.0"             xmlns:sci="urn:ietf:params:xml:ns:iodef-sci-1.0"             xmlns:xs="http://www.w3.org/2001/XMLSchema"             xmlns:ds="http://www.w3.org/2000/09/xmldsig#"             targetNamespace="urn:ietf:params:xml:ns:iodef-2.0"             elementFormDefault="qualified"             attributeFormDefault="unqualified">    <xs:import namespace="http://www.w3.org/2000/09/xmldsig#"               schemaLocation="http://www.w3.org/TR/2002/  REC-xmldsig-core-20020212/xmldsig-core-schema.xsd"/>    <xs:import namespace="urn:ietf:params:xml:ns:iodef-enum-1.0"               schemaLocation="http://www.iana.org/assignments/  xml-registry/schema/iodef-enum-1.0.xsd"/>    <xs:import namespace="urn:ietf:params:xml:ns:iodef-sci-1.0"               schemaLocation="http://www.iana.org/assignments/  xml-registry/schema/iodef-sci-1.0.xsd"/>    <xs:import namespace="http://www.w3.org/XML/1998/namespace"               schemaLocation="http://www.w3c.org/2001/xml.xsd"/>    <xs:annotation>      <xs:documentation>         Incident Object Description Exchange Format v2.0Danyliw                      Standards Track                  [Page 121]

RFC 7970                     IODEF Version 2               November 2016      </xs:documentation>    </xs:annotation>    <!--     ===================================================================     == IODEF-Document class                                          ==     ===================================================================    -->    <xs:element name="IODEF-Document">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Incident" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="version" type="xs:string" fixed="2.00"/>        <xs:attribute ref="xml:lang"/>        <xs:attribute name="format-id" type="xs:string" use="optional"/>        <xs:attribute name="private-enum-name"                      type="xs:string" use="optional"/>        <xs:attribute name="private-enum-id"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <!--     ===================================================================     == Incident class                                                ==     ===================================================================    -->    <xs:element name="Incident">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:IncidentID"/>          <xs:element ref="iodef:AlternativeID" minOccurs="0"/>          <xs:element ref="iodef:RelatedActivity"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:DetectTime" minOccurs="0"/>          <xs:element ref="iodef:StartTime" minOccurs="0"/>          <xs:element ref="iodef:EndTime" minOccurs="0"/>          <xs:element ref="iodef:RecoveryTime" minOccurs="0"/>          <xs:element ref="iodef:ReportTime" minOccurs="0"/>          <xs:element ref="iodef:GenerationTime"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Discovery"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Assessment"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Method"Danyliw                      Standards Track                  [Page 122]

RFC 7970                     IODEF Version 2               November 2016                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Contact" maxOccurs="unbounded"/>          <xs:element ref="iodef:EventData"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:IndicatorData" minOccurs="0"/>          <xs:element ref="iodef:History" minOccurs="0"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="purpose"                      type="incident-purpose-type" use="required"/>        <xs:attribute name="ext-purpose"                      type="xs:string" use="optional"/>        <xs:attribute name="status" type="incident-status-type"/>        <xs:attribute name="ext-status"                      type="xs:string" use="optional"/>        <xs:attribute ref="xml:lang"/>        <xs:attribute name="restriction"                      type="iodef:restriction-type" default="private"                      use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="incident-purpose-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="traceback"/>        <xs:enumeration value="mitigation"/>        <xs:enumeration value="reporting"/>        <xs:enumeration value="watch"/>        <xs:enumeration value="other"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="incident-status-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="new"/>        <xs:enumeration value="in-progress"/>        <xs:enumeration value="forwarded"/>        <xs:enumeration value="resolved"/>        <xs:enumeration value="future"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>Danyliw                      Standards Track                  [Page 123]

RFC 7970                     IODEF Version 2               November 2016    <!--     ===================================================================     ==  IncidentID class                                             ==     ===================================================================    -->    <xs:element name="IncidentID" type="iodef:IncidentIDType"/>    <xs:complexType name="IncidentIDType">      <xs:simpleContent>        <xs:extension base="xs:string">          <xs:attribute name="name" type="xs:string" use="required"/>          <xs:attribute name="instance"                        type="xs:string" use="optional"/>          <xs:attribute name="restriction"                        type="iodef:restriction-type" use="optional"/>          <xs:attribute name="ext-restriction"                        type="xs:string" use="optional"/>        </xs:extension>      </xs:simpleContent>    </xs:complexType>    <!--     ==================================================================     ==  AlternativeID class                                         ==     ==================================================================    -->    <xs:element name="AlternativeID">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:IncidentID" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <!--     ===================================================================     ==  RelatedActivity class                                        ==     ===================================================================    -->    <xs:element name="RelatedActivity">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:IncidentID"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:URL"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:ThreatActor"Danyliw                      Standards Track                  [Page 124]

RFC 7970                     IODEF Version 2               November 2016                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Campaign"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:IndicatorID"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Confidence" minOccurs="0"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="ThreatActor">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:ThreatActorID"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:URL" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="ThreatActorID" type="xs:string"/>    <xs:element name="Campaign">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:CampaignID"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:URL"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"Danyliw                      Standards Track                  [Page 125]

RFC 7970                     IODEF Version 2               November 2016                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="CampaignID" type="xs:string"/>    <!--     ===================================================================     ==   Contact class                                               ==     ===================================================================    -->    <xs:element name="Contact">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:ContactName"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:ContactTitle"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:RegistryHandle"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:PostalAddress"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Email"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Telephone"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Timezone" minOccurs="0"/>          <xs:element ref="iodef:Contact"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="role"                      type="contact-role-type" use="required"/>        <xs:attribute name="ext-role"                      type="xs:string" use="optional"/>        <xs:attribute name="type"                      type="contact-type-type" use="required"/>        <xs:attribute name="ext-type"                      type="xs:string" use="optional"/>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>Danyliw                      Standards Track                  [Page 126]

RFC 7970                     IODEF Version 2               November 2016    <xs:simpleType name="contact-role-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="creator"/>        <xs:enumeration value="reporter"/>        <xs:enumeration value="admin"/>        <xs:enumeration value="tech"/>        <xs:enumeration value="provider"/>        <xs:enumeration value="user"/>        <xs:enumeration value="billing"/>        <xs:enumeration value="legal"/>        <xs:enumeration value="abuse"/>        <xs:enumeration value="irt"/>        <xs:enumeration value="cc"/>        <xs:enumeration value="cc-irt"/>        <xs:enumeration value="leo"/>        <xs:enumeration value="vendor"/>        <xs:enumeration value="vendor-services"/>        <xs:enumeration value="victim"/>        <xs:enumeration value="victim-notified"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="contact-type-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="person"/>        <xs:enumeration value="organization"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="ContactName" type="iodef:MLStringType"/>    <xs:element name="ContactTitle" type="iodef:MLStringType"/>    <xs:element name="RegistryHandle">      <xs:complexType>        <xs:simpleContent>          <xs:extension base="xs:string">            <xs:attribute name="registry"                          type="registryhandle-registry-type"/>            <xs:attribute name="ext-registry"                          type="xs:string" use="optional"/>          </xs:extension>        </xs:simpleContent>      </xs:complexType>    </xs:element>    <xs:simpleType name="registryhandle-registry-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="internic"/>        <xs:enumeration value="apnic"/>        <xs:enumeration value="arin"/>Danyliw                      Standards Track                  [Page 127]

RFC 7970                     IODEF Version 2               November 2016        <xs:enumeration value="lacnic"/>        <xs:enumeration value="ripe"/>        <xs:enumeration value="afrinic"/>        <xs:enumeration value="local"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="PostalAddress">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:PAddress"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="type"                      type="postaladdress-type-type" use="optional"/>        <xs:attribute name="ext-type" type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="PAddress" type="iodef:MLStringType"/>    <xs:simpleType name="postaladdress-type-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="street"/>        <xs:enumeration value="mailing"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="Telephone">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:TelephoneNumber"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="type"                      type="telephone-type-type" use="optional"/>        <xs:attribute name="ext-type" type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="TelephoneNumber" type="xs:string"/>    <xs:simpleType name="telephone-type-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="wired"/>        <xs:enumeration value="mobile"/>        <xs:enumeration value="fax"/>        <xs:enumeration value="hotline"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>Danyliw                      Standards Track                  [Page 128]

RFC 7970                     IODEF Version 2               November 2016    </xs:simpleType>    <xs:element name="Email">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:EmailTo"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="type"                      type="email-type-type" use="optional"/>        <xs:attribute name="ext-type" type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="email-type-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="direct"/>        <xs:enumeration value="hotline"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <!--     ===================================================================     ==  Time-based classes                                           ==     ===================================================================    -->    <xs:element name="DateTime" type="xs:dateTime"/>    <xs:element name="ReportTime" type="xs:dateTime"/>    <xs:element name="DetectTime" type="xs:dateTime"/>    <xs:element name="StartTime" type="xs:dateTime"/>    <xs:element name="EndTime" type="xs:dateTime"/>    <xs:element name="RecoveryTime" type="xs:dateTime"/>    <xs:element name="GenerationTime" type="xs:dateTime"/>    <xs:element name="Timezone" type="iodef:TimezoneType"/>    <!--     ===================================================================     ==  History class                                                ==     ===================================================================    -->    <xs:element name="History">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:HistoryItem" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>Danyliw                      Standards Track                  [Page 129]

RFC 7970                     IODEF Version 2               November 2016    </xs:element>    <xs:element name="HistoryItem">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:DateTime"/>          <xs:element ref="iodef:IncidentID" minOccurs="0"/>          <xs:element ref="iodef:Contact" minOccurs="0"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:DefinedCOA"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="action"                      type="iodef:action-type" use="required"/>        <xs:attribute name="ext-action"                      type="xs:string" use="optional"/>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="DefinedCOA" type="xs:string"/>    <!--     ===================================================================     ==  Expectation class                                            ==     ===================================================================    -->    <xs:element name="Expectation">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:DefinedCOA"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:StartTime" minOccurs="0"/>          <xs:element ref="iodef:EndTime" minOccurs="0"/>          <xs:element ref="iodef:Contact" minOccurs="0"/>        </xs:sequence>        <xs:attribute name="action"                      type="iodef:action-type" default="other"/>        <xs:attribute name="ext-action"                      type="xs:string" use="optional"/>        <xs:attribute name="severity" type="iodef:severity-type"/>        <xs:attribute name="restriction"Danyliw                      Standards Track                  [Page 130]

RFC 7970                     IODEF Version 2               November 2016                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <!--     ===================================================================     ==  Discovery class                                              ==     ===================================================================    -->    <xs:element name="Discovery">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Contact"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:DetectionPattern"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="source"                      type="discovery-source-type" use="optional"                      default="unknown"/>        <xs:attribute name="ext-source"                      type="xs:string" use="optional"/>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="discovery-source-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="nidps"/>        <xs:enumeration value="hips"/>        <xs:enumeration value="siem"/>        <xs:enumeration value="av"/>        <xs:enumeration value="third-party-monitoring"/>        <xs:enumeration value="incident"/>        <xs:enumeration value="os-log"/>        <xs:enumeration value="application-log"/>        <xs:enumeration value="device-log"/>        <xs:enumeration value="network-flow"/>        <xs:enumeration value="passive-dns"/>        <xs:enumeration value="investigation"/>        <xs:enumeration value="audit"/>        <xs:enumeration value="internal-notification"/>Danyliw                      Standards Track                  [Page 131]

RFC 7970                     IODEF Version 2               November 2016        <xs:enumeration value="external-notification"/>        <xs:enumeration value="leo"/>        <xs:enumeration value="partner"/>        <xs:enumeration value="actor"/>        <xs:enumeration value="unknown"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="DetectionPattern">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Application"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element name="DetectionConfiguration"                      type="xs:string"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <!--     ===================================================================     ==  Method class                                                 ==     ===================================================================    -->    <xs:element name="Method">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Reference"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="sci:AttackPattern"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="sci:Vulnerability"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="sci:Weakness"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>Danyliw                      Standards Track                  [Page 132]

RFC 7970                     IODEF Version 2               November 2016        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <!--     ===================================================================     ==  Reference class                                              ==     ===================================================================    -->    <xs:element name="Reference">      <xs:complexType>        <xs:sequence>          <xs:element ref="enum:ReferenceName" minOccurs="0"/>          <xs:element ref="iodef:URL"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <!--     ===================================================================     ==  Assessment class                                             ==     ===================================================================    -->    <xs:element name="Assessment">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:IncidentCategory"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:choice maxOccurs="unbounded">            <xs:element ref="iodef:SystemImpact"/>            <xs:element ref="iodef:BusinessImpact"/>            <xs:element ref="iodef:TimeImpact"/>            <xs:element ref="iodef:MonetaryImpact"/>            <xs:element ref="iodef:IntendedImpact"/>          </xs:choice>          <xs:element ref="iodef:Counter"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:MitigatingFactor"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Cause"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Confidence" minOccurs="0"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>Danyliw                      Standards Track                  [Page 133]

RFC 7970                     IODEF Version 2               November 2016        <xs:attribute name="occurrence">          <xs:simpleType>            <xs:restriction base="xs:NMTOKEN">              <xs:enumeration value="actual"/>              <xs:enumeration value="potential"/>            </xs:restriction>          </xs:simpleType>        </xs:attribute>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="IncidentCategory" type="iodef:MLStringType"/>    <xs:element name="BusinessImpact" type="iodef:BusinessImpactType"/>    <xs:element name="IntendedImpact" type="iodef:BusinessImpactType"/>    <xs:element name="MitigatingFactor" type="iodef:MLStringType"/>    <xs:element name="Cause" type="iodef:MLStringType"/>    <xs:element name="SystemImpact">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="severity"                      type="iodef:severity-type" use="optional"/>        <xs:attribute name="completion"                      type="iodef:systemimpact-completion-type"                      use="optional"/>        <xs:attribute name="type"                      type="systemimpact-type-type"                      use="optional" default="unknown"/>        <xs:attribute name="ext-type" type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="systemimpact-completion-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="failed"/>        <xs:enumeration value="succeeded"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="systemimpact-type-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="takeover-account"/>        <xs:enumeration value="takeover-service"/>        <xs:enumeration value="takeover-system"/>Danyliw                      Standards Track                  [Page 134]

RFC 7970                     IODEF Version 2               November 2016        <xs:enumeration value="cps-manipulation"/>        <xs:enumeration value="cps-damage"/>        <xs:enumeration value="availability-data"/>        <xs:enumeration value="availability-account"/>        <xs:enumeration value="availability-service"/>        <xs:enumeration value="availability-system"/>        <xs:enumeration value="damaged-system"/>        <xs:enumeration value="damaged-data"/>        <xs:enumeration value="breach-proprietary"/>        <xs:enumeration value="breach-privacy"/>        <xs:enumeration value="breach-credential"/>        <xs:enumeration value="breach-configuration"/>        <xs:enumeration value="integrity-data"/>        <xs:enumeration value="integrity-configuration"/>        <xs:enumeration value="integrity-hardware"/>        <xs:enumeration value="traffic-redirection"/>        <xs:enumeration value="monitoring-traffic"/>        <xs:enumeration value="monitoring-host"/>        <xs:enumeration value="policy"/>        <xs:enumeration value="unknown"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:complexType name="BusinessImpactType">      <xs:sequence>        <xs:element ref="iodef:Description"                    minOccurs="0" maxOccurs="unbounded"/>      </xs:sequence>      <xs:attribute name="severity"                    type="businessimpact-severity-type" use="optional"/>      <xs:attribute name="ext-severity"                    type="xs:string" use="optional"/>      <xs:attribute name="type"                    type="businessimpact-type-type"                    use="optional" default="unknown"/>      <xs:attribute name="ext-type" type="xs:string" use="optional"/>    </xs:complexType>    <xs:simpleType name="businessimpact-severity-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="none"/>        <xs:enumeration value="low"/>        <xs:enumeration value="medium"/>        <xs:enumeration value="high"/>        <xs:enumeration value="unknown"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="businessimpact-type-type">Danyliw                      Standards Track                  [Page 135]

RFC 7970                     IODEF Version 2               November 2016      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="breach-proprietary"/>        <xs:enumeration value="breach-privacy"/>        <xs:enumeration value="breach-credential"/>        <xs:enumeration value="loss-of-integrity"/>        <xs:enumeration value="loss-of-service"/>        <xs:enumeration value="theft-financial"/>        <xs:enumeration value="theft-service"/>        <xs:enumeration value="degraded-reputation"/>        <xs:enumeration value="asset-damage"/>        <xs:enumeration value="asset-manipulation"/>        <xs:enumeration value="legal"/>        <xs:enumeration value="extortion"/>        <xs:enumeration value="unknown"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="TimeImpact">      <xs:complexType>        <xs:simpleContent>          <xs:extension base="iodef:PositiveFloatType">            <xs:attribute name="severity" type="iodef:severity-type"/>            <xs:attribute name="metric"                          type="timeimpact-metric-type" use="required"/>            <xs:attribute name="ext-metric"                          type="xs:string" use="optional"/>            <xs:attribute name="duration" type="iodef:duration-type"/>            <xs:attribute name="ext-duration"                          type="xs:string" use="optional"/>          </xs:extension>        </xs:simpleContent>      </xs:complexType>    </xs:element>    <xs:simpleType name="timeimpact-metric-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="labor"/>        <xs:enumeration value="elapsed"/>        <xs:enumeration value="downtime"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="MonetaryImpact">      <xs:complexType>        <xs:simpleContent>          <xs:extension base="iodef:PositiveFloatType">            <xs:attribute name="severity" type="iodef:severity-type"/>            <xs:attribute name="currency" type="xs:string"/>          </xs:extension>Danyliw                      Standards Track                  [Page 136]

RFC 7970                     IODEF Version 2               November 2016        </xs:simpleContent>      </xs:complexType>    </xs:element>    <xs:element name="Confidence">      <xs:complexType>        <xs:attribute name="rating"                      type="confidence-rating-type" use="required"/>        <xs:attribute name="ext-rating"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="confidence-rating-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="low"/>        <xs:enumeration value="medium"/>        <xs:enumeration value="high"/>        <xs:enumeration value="numeric"/>        <xs:enumeration value="unknown"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <!--     ===================================================================     == EventData class                                               ==     ===================================================================    -->    <xs:element name="EventData">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:DetectTime" minOccurs="0"/>          <xs:element ref="iodef:StartTime" minOccurs="0"/>          <xs:element ref="iodef:EndTime" minOccurs="0"/>          <xs:element ref="iodef:RecoveryTime" minOccurs="0"/>          <xs:element ref="iodef:ReportTime" minOccurs="0"/>          <xs:element ref="iodef:Contact"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Discovery"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Assessment" minOccurs="0"/>          <xs:element ref="iodef:Method"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Flow"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Expectation"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Record" minOccurs="0"/>Danyliw                      Standards Track                  [Page 137]

RFC 7970                     IODEF Version 2               November 2016          <xs:element ref="iodef:EventData"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <!--     ===================================================================     ==  Flow class                                                   ==     ===================================================================    -->    <xs:element name="Flow">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:System" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <!--     ===================================================================     ==  System class                                                 ==     ===================================================================    -->    <xs:element name="System">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Node"/>          <xs:element ref="iodef:NodeRole"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Service"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:OperatingSystem"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Counter"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element name="AssetID"                      type="xs:string"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>Danyliw                      Standards Track                  [Page 138]

RFC 7970                     IODEF Version 2               November 2016        </xs:sequence>        <xs:attribute name="category" type="system-category-type"/>        <xs:attribute name="ext-category"                      type="xs:string" use="optional"/>        <xs:attribute name="interface" type="xs:string"/>        <xs:attribute name="spoofed"                      type="yes-no-unknown-type" default="unknown"/>        <xs:attribute name="virtual"                      type="yes-no-unknown-type" use="optional"                      default="unknown"/>        <xs:attribute name="ownership" type="system-ownership-type"                      use="optional"/>        <xs:attribute name="ext-ownership"                      type="xs:string" use="optional"/>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="OperatingSystem" type="iodef:SoftwareType"/>    <xs:simpleType name="system-category-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="source"/>        <xs:enumeration value="target"/>        <xs:enumeration value="intermediate"/>        <xs:enumeration value="sensor"/>        <xs:enumeration value="infrastructure"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="system-ownership-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="organization"/>        <xs:enumeration value="personal"/>        <xs:enumeration value="partner"/>        <xs:enumeration value="customer"/>        <xs:enumeration value="no-relationship"/>        <xs:enumeration value="unknown"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <!--     ==================================================================     == Node class                                                   ==     ==================================================================    -->Danyliw                      Standards Track                  [Page 139]

RFC 7970                     IODEF Version 2               November 2016    <xs:element name="Node">      <xs:complexType>        <xs:sequence>          <xs:choice maxOccurs="unbounded">            <xs:element ref="iodef:DomainData"                        minOccurs="0" maxOccurs="unbounded"/>            <xs:element ref="iodef:Address"                        minOccurs="0" maxOccurs="unbounded"/>          </xs:choice>          <xs:element ref="iodef:PostalAddress" minOccurs="0"/>          <xs:element ref="iodef:Location"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Counter"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="Address">      <xs:complexType>        <xs:simpleContent>          <xs:extension base="xs:string">            <xs:attribute name="category"                          type="address-category-type"                          default="ipv6-addr"/>            <xs:attribute name="ext-category"                          type="xs:string" use="optional"/>            <xs:attribute name="vlan-name" type="xs:string"/>            <xs:attribute name="vlan-num" type="xs:integer"/>            <xs:attribute name="observable-id"                          type="xs:ID" use="optional"/>          </xs:extension>        </xs:simpleContent>      </xs:complexType>    </xs:element>    <xs:simpleType name="address-category-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="asn"/>        <xs:enumeration value="atm"/>        <xs:enumeration value="e-mail"/>        <xs:enumeration value="mac"/>        <xs:enumeration value="ipv4-addr"/>        <xs:enumeration value="ipv4-net"/>        <xs:enumeration value="ipv4-net-masked"/>        <xs:enumeration value="ipv4-net-mask"/>        <xs:enumeration value="ipv6-addr"/>        <xs:enumeration value="ipv6-net"/>        <xs:enumeration value="ipv6-net-masked"/>        <xs:enumeration value="site-uri"/>Danyliw                      Standards Track                  [Page 140]

RFC 7970                     IODEF Version 2               November 2016        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="Location" type="iodef:MLStringType"/>    <xs:element name="NodeRole">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="category"                      type="noderole-category-type" use="required"/>        <xs:attribute name="ext-category"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="noderole-category-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="client"/>        <xs:enumeration value="client-enterprise"/>        <xs:enumeration value="client-partner"/>        <xs:enumeration value="client-remote"/>        <xs:enumeration value="client-kiosk"/>        <xs:enumeration value="client-mobile"/>        <xs:enumeration value="server-internal"/>        <xs:enumeration value="server-public"/>        <xs:enumeration value="www"/>        <xs:enumeration value="mail"/>        <xs:enumeration value="webmail"/>        <xs:enumeration value="messaging"/>        <xs:enumeration value="streaming"/>        <xs:enumeration value="voice"/>        <xs:enumeration value="file"/>        <xs:enumeration value="ftp"/>        <xs:enumeration value="p2p"/>        <xs:enumeration value="name"/>        <xs:enumeration value="directory"/>        <xs:enumeration value="credential"/>        <xs:enumeration value="print"/>        <xs:enumeration value="application"/>        <xs:enumeration value="database"/>        <xs:enumeration value="backup"/>        <xs:enumeration value="dhcp"/>        <xs:enumeration value="assessment"/>        <xs:enumeration value="source-control"/>        <xs:enumeration value="config-management"/>        <xs:enumeration value="monitoring"/>        <xs:enumeration value="infra"/>Danyliw                      Standards Track                  [Page 141]

RFC 7970                     IODEF Version 2               November 2016        <xs:enumeration value="infra-firewall"/>        <xs:enumeration value="infra-router"/>        <xs:enumeration value="infra-switch"/>        <xs:enumeration value="camera"/>        <xs:enumeration value="proxy"/>        <xs:enumeration value="remote-access"/>        <xs:enumeration value="log"/>        <xs:enumeration value="virtualization"/>        <xs:enumeration value="pos"/>        <xs:enumeration value="scada"/>        <xs:enumeration value="scada-supervisory"/>        <xs:enumeration value="sinkhole"/>        <xs:enumeration value="honeypot"/>        <xs:enumeration value="anonymization"/>        <xs:enumeration value="c2-server"/>        <xs:enumeration value="malware-distribution"/>        <xs:enumeration value="drop-server"/>        <xs:enumeration value="hop-point"/>        <xs:enumeration value="reflector"/>        <xs:enumeration value="phishing-site"/>        <xs:enumeration value="spear-phishing-site"/>        <xs:enumeration value="recruiting-site"/>        <xs:enumeration value="fraudulent-site"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <!--     ===================================================================     ==  Service class                                                ==     ===================================================================    -->    <xs:element name="Service">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:ServiceName" minOccurs="0"/>          <xs:element ref="iodef:Port" minOccurs="0"/>          <xs:element ref="iodef:Portlist" minOccurs="0"/>          <xs:element ref="iodef:ProtoType" minOccurs="0"/>          <xs:element ref="iodef:ProtoCode" minOccurs="0"/>          <xs:element ref="iodef:ProtoField" minOccurs="0"/>          <xs:element ref="iodef:ApplicationHeader" minOccurs="0"/>          <xs:element ref="iodef:EmailData" minOccurs="0"/>          <xs:element ref="iodef:Application" minOccurs="0"/>        </xs:sequence>        <xs:attribute name="ip-protocol"                      type="xs:integer" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>Danyliw                      Standards Track                  [Page 142]

RFC 7970                     IODEF Version 2               November 2016    </xs:element>    <xs:element name="Port" type="xs:integer"/>    <xs:element name="Portlist" type="iodef:PortlistType"/>    <xs:element name="ProtoType" type="xs:integer"/>    <xs:element name="ProtoCode" type="xs:integer"/>    <xs:element name="ProtoField" type="xs:integer"/>    <xs:element name="ApplicationHeader">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:ApplicationHeaderField"                      maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="ApplicationHeaderField"                type="iodef:ExtensionType"/>    <xs:element name="ServiceName">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:IANAService"                      minOccurs="0"/>          <xs:element ref="iodef:URL"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="IANAService" type="xs:string"/>    <xs:element name="Application" type="iodef:SoftwareType"/>    <!--     ===================================================================     ==  Counter class                                                ==     ===================================================================    -->    <xs:element name="Counter">      <xs:complexType>        <xs:simpleContent>          <xs:extension base="xs:float">            <xs:attribute name="type"                          type="counter-type-type" use="required"/>            <xs:attribute name="ext-type"                          type="xs:string" use="optional"/>            <xs:attribute name="unit"                          type="counter-unit-type" use="required"/>            <xs:attribute name="ext-unit"                          type="xs:string" use="optional"/>            <xs:attribute name="meaning"Danyliw                      Standards Track                  [Page 143]

RFC 7970                     IODEF Version 2               November 2016                          type="xs:string" use="optional"/>            <xs:attribute name="duration" type="iodef:duration-type"/>            <xs:attribute name="ext-duration"                          type="xs:string" use="optional"/>          </xs:extension>        </xs:simpleContent>      </xs:complexType>    </xs:element>    <xs:simpleType name="counter-type-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="counter"/>        <xs:enumeration value="rate"/>        <xs:enumeration value="average"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="counter-unit-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="byte"/>        <xs:enumeration value="mbit"/>        <xs:enumeration value="packet"/>        <xs:enumeration value="flow"/>        <xs:enumeration value="session"/>        <xs:enumeration value="event"/>        <xs:enumeration value="alert"/>        <xs:enumeration value="message"/>        <xs:enumeration value="host"/>        <xs:enumeration value="site"/>        <xs:enumeration value="organization"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <!--     ===================================================================     ==  EmailData class                                              ==     ===================================================================    -->    <xs:element name="EmailData">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:EmailTo"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:EmailFrom" minOccurs="0"/>          <xs:element ref="iodef:EmailSubject" minOccurs="0"/>          <xs:element ref="iodef:EmailX-Mailer" minOccurs="0"/>          <xs:element ref="iodef:EmailHeaderField"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:EmailHeaders" minOccurs="0"/>Danyliw                      Standards Track                  [Page 144]

RFC 7970                     IODEF Version 2               November 2016          <xs:element ref="iodef:EmailBody" minOccurs="0"/>          <xs:element ref="iodef:EmailMessage" minOccurs="0"/>          <xs:element ref="iodef:HashData"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="SignatureData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="EmailTo" type="xs:string"/>    <xs:element name="EmailFrom" type="xs:string"/>    <xs:element name="EmailSubject" type="xs:string"/>    <xs:element name="EmailX-Mailer" type="xs:string"/>    <xs:element name="EmailHeaderField" type="iodef:ExtensionType"/>    <xs:element name="EmailHeaders" type="xs:string"/>    <xs:element name="EmailBody" type="xs:string"/>    <xs:element name="EmailMessage" type="xs:string"/>    <!--     ===================================================================     ==   DomainData class                                            ==     ===================================================================    -->    <xs:element name="DomainData">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Name"/>          <xs:element ref="iodef:DateDomainWasChecked"                      minOccurs="0"/>          <xs:element ref="iodef:RegistrationDate"                      minOccurs="0"/>          <xs:element ref="iodef:ExpirationDate"                      minOccurs="0"/>          <xs:element ref="iodef:RelatedDNS"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Nameservers"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:DomainContacts"                      minOccurs="0"/>        </xs:sequence>        <xs:attribute name="system-status"                      type="domaindata-system-status-type"/>        <xs:attribute name="ext-system-status"                      type="xs:string" use="optional"/>        <xs:attribute name="domain-status"                      type="domaindata-domain-status-type"/>        <xs:attribute name="ext-domain-status"                      type="xs:string" use="optional"/>Danyliw                      Standards Track                  [Page 145]

RFC 7970                     IODEF Version 2               November 2016        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="Name" type="xs:string"/>    <xs:element name="DateDomainWasChecked" type="xs:dateTime"/>    <xs:element name="RegistrationDate" type="xs:dateTime"/>    <xs:element name="ExpirationDate" type="xs:dateTime"/>    <xs:simpleType name="domaindata-system-status-type">      <xs:restriction base="xs:string">        <xs:enumeration value="spoofed"/>        <xs:enumeration value="fraudulent"/>        <xs:enumeration value="innocent-hacked"/>        <xs:enumeration value="innocent-hijacked"/>        <xs:enumeration value="unknown"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="domaindata-domain-status-type">      <xs:restriction base="xs:string">        <xs:enumeration value="reservedDelegation"/>        <xs:enumeration value="assignedAndActive"/>        <xs:enumeration value="assignedAndInactive"/>        <xs:enumeration value="assignedAndOnHold"/>        <xs:enumeration value="revoked"/>        <xs:enumeration value="transferPending"/>        <xs:enumeration value="registryLock"/>        <xs:enumeration value="registrarLock"/>        <xs:enumeration value="other"/>        <xs:enumeration value="unknown"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="RelatedDNS" type="iodef:ExtensionType"/>    <xs:element name="Nameservers">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Server"/>          <xs:element ref="iodef:Address" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="Server" type="xs:string"/>    <xs:element name="DomainContacts">      <xs:complexType>        <xs:choice>          <xs:element ref="iodef:SameDomainContact"/>          <xs:element ref="iodef:Contact"                      minOccurs="1" maxOccurs="unbounded"/>Danyliw                      Standards Track                  [Page 146]

RFC 7970                     IODEF Version 2               November 2016        </xs:choice>      </xs:complexType>    </xs:element>    <xs:element name="SameDomainContact" type="xs:string"/>    <!--     ===================================================================     ==  Record class                                                 ==     ===================================================================    -->    <xs:element name="Record">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:RecordData" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="RecordData">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:DateTime" minOccurs="0"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Application" minOccurs="0"/>          <xs:element ref="iodef:RecordPattern"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:RecordItem"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:URL"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:FileData"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:WindowsRegistryKeysModified"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:CertificateData"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>Danyliw                      Standards Track                  [Page 147]

RFC 7970                     IODEF Version 2               November 2016    </xs:element>    <xs:element name="RecordPattern">      <xs:complexType>        <xs:simpleContent>          <xs:extension base="xs:string">            <xs:attribute name="type"                          type="recordpattern-type-type"                          use="required"/>            <xs:attribute name="ext-type"                          type="xs:string" use="optional"/>            <xs:attribute name="offset"                          type="xs:integer" use="optional"/>            <xs:attribute name="offsetunit"                          type="recordpattern-offsetunit-type"                          use="optional" default="line"/>            <xs:attribute name="ext-offsetunit"                          type="xs:string" use="optional"/>            <xs:attribute name="instance"                          type="xs:integer" use="optional"/>          </xs:extension>        </xs:simpleContent>      </xs:complexType>    </xs:element>    <xs:simpleType name="recordpattern-type-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="regex"/>        <xs:enumeration value="binary"/>        <xs:enumeration value="xpath"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="recordpattern-offsetunit-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="line"/>        <xs:enumeration value="byte"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="RecordItem" type="iodef:ExtensionType"/>    <!--     ===================================================================     ==  WindowsRegistryKeysModified class                            ==     ===================================================================    -->    <xs:element name="WindowsRegistryKeysModified">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Key" maxOccurs="unbounded"/>Danyliw                      Standards Track                  [Page 148]

RFC 7970                     IODEF Version 2               November 2016        </xs:sequence>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="Key">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:KeyName"/>          <xs:element ref="iodef:Value" minOccurs="0"/>        </xs:sequence>        <xs:attribute name="registryaction"                      type="key-registryaction-type"/>        <xs:attribute name="ext-registryaction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="KeyName" type="xs:string"/>    <xs:element name="Value" type="xs:string"/>    <xs:simpleType name="key-registryaction-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="add-key"/>        <xs:enumeration value="add-value"/>        <xs:enumeration value="delete-key"/>        <xs:enumeration value="delete-value"/>        <xs:enumeration value="modify-key"/>        <xs:enumeration value="modify-value"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <!--    ====================================================================    ==  FileData class                                                ==    ====================================================================    -->    <xs:element name="FileData">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:File"                      minOccurs="1" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>Danyliw                      Standards Track                  [Page 149]

RFC 7970                     IODEF Version 2               November 2016    <xs:element name="File">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:FileName" minOccurs="0"/>          <xs:element ref="iodef:FileSize" minOccurs="0"/>          <xs:element ref="FileType" minOccurs="0"/>          <xs:element ref="iodef:URL"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:HashData" minOccurs="0"/>          <xs:element ref="iodef:SignatureData" minOccurs="0"/>          <xs:element ref="iodef:AssociatedSoftware" minOccurs="0"/>          <xs:element ref="iodef:FileProperties"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="FileName" type="xs:string"/>    <xs:element name="FileSize" type="xs:integer"/>    <xs:element name="FileType" type="xs:string"/>    <xs:element name="AssociatedSoftware" type="iodef:SoftwareType"/>    <xs:element name="FileProperties" type="iodef:ExtensionType"/>    <!--    ====================================================================    ==  HashData class                                                ==    ====================================================================    -->    <xs:element name="HashData">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:HashTargetID" minOccurs="0"/>          <xs:element ref="iodef:Hash"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:FuzzyHash"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="scope"                      type="hashdata-scope-type" use="required"/>        <xs:attribute name="ext-scope" type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="HashTargetID" type="xs:string"/>    <xs:simpleType name="hashdata-scope-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="file-contents"/>        <xs:enumeration value="file-pe-section"/>        <xs:enumeration value="file-pe-iat"/>        <xs:enumeration value="file-pe-resource"/>Danyliw                      Standards Track                  [Page 150]

RFC 7970                     IODEF Version 2               November 2016        <xs:enumeration value="file-pdf-object"/>        <xs:enumeration value="email-hash"/>        <xs:enumeration value="email-headers-hash"/>        <xs:enumeration value="email-body-hash"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="Hash">      <xs:complexType>        <xs:sequence>          <xs:element ref="ds:DigestMethod"/>          <xs:element ref="ds:DigestValue"/>          <xs:element ref="ds:CanonicalizationMethod"                      minOccurs="0"/>          <xs:element ref="iodef:Application" minOccurs="0"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="FuzzyHash">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:FuzzyHashValue"                      maxOccurs="unbounded"/>          <xs:element ref="iodef:Application" minOccurs="0"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="FuzzyHashValue" type="iodef:ExtensionType"/>    <!--     ===================================================================     ==  SignatureData class                                          ==     ===================================================================    -->    <xs:element name="SignatureData">      <xs:complexType>        <xs:sequence>          <xs:element ref="ds:Signature" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <!--     ===================================================================     ==  CertificateData class                                        ==     ===================================================================    -->    <xs:element name="CertificateData">Danyliw                      Standards Track                  [Page 151]

RFC 7970                     IODEF Version 2               November 2016      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Certificate" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="Certificate">      <xs:complexType>        <xs:sequence>          <xs:element ref="ds:X509Data"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="observable-id" type="xs:ID" use="optional"/>      </xs:complexType>    </xs:element>    <!--     ===================================================================     == IndicatorData class                                           ==     ===================================================================    -->    <xs:element name="IndicatorData">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Indicator"                      minOccurs="1" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="Indicator">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:IndicatorID"/>          <xs:element ref="iodef:AlternativeIndicatorID"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:StartTime" minOccurs="0"/>          <xs:element ref="iodef:EndTime" minOccurs="0"/>          <xs:element ref="iodef:Confidence" minOccurs="0"/>          <xs:element ref="iodef:Contact"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:choice>Danyliw                      Standards Track                  [Page 152]

RFC 7970                     IODEF Version 2               November 2016            <xs:element ref="iodef:Observable"/>            <xs:element ref="iodef:ObservableReference"/>            <xs:element ref="iodef:IndicatorExpression"/>            <xs:element ref="iodef:IndicatorReference"/>          </xs:choice>          <xs:element ref="iodef:NodeRole"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AttackPhase"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:Reference"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="IndicatorID">      <xs:complexType>        <xs:simpleContent>          <xs:extension base="xs:ID">            <xs:attribute name="name" type="xs:string" use="required"/>            <xs:attribute name="version"                          type="xs:string" use="required"/>          </xs:extension>        </xs:simpleContent>      </xs:complexType>    </xs:element>    <xs:element name="AlternativeIndicatorID">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:IndicatorID" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="Observable">      <xs:complexType>        <xs:choice>          <xs:element ref="iodef:System" minOccurs="0"/>          <xs:element ref="iodef:Address" minOccurs="0"/>          <xs:element ref="iodef:DomainData" minOccurs="0"/>Danyliw                      Standards Track                  [Page 153]

RFC 7970                     IODEF Version 2               November 2016          <xs:element ref="iodef:Service" minOccurs="0"/>          <xs:element ref="iodef:EmailData" minOccurs="0"/>          <xs:element ref="iodef:WindowsRegistryKeysModified"                           minOccurs="0"/>          <xs:element ref="iodef:FileData" minOccurs="0"/>          <xs:element ref="iodef:CertificateData" minOccurs="0"/>          <xs:element ref="iodef:RegistryHandle" minOccurs="0"/>          <xs:element ref="iodef:RecordData" minOccurs="0"/>          <xs:element ref="iodef:EventData" minOccurs="0"/>          <xs:element ref="iodef:Incident" minOccurs="0"/>          <xs:element ref="iodef:Expectation" minOccurs="0"/>          <xs:element ref="iodef:Reference" minOccurs="0"/>          <xs:element ref="iodef:Assessment" minOccurs="0"/>          <xs:element ref="iodef:DetectionPattern" minOccurs="0"/>          <xs:element ref="iodef:HistoryItem" minOccurs="0"/>          <xs:element ref="iodef:BulkObservable" minOccurs="0"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:choice>        <xs:attribute name="restriction"                      type="iodef:restriction-type" use="optional"/>        <xs:attribute name="ext-restriction"                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="BulkObservable">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:BulkObservableFormat" minOccurs="0"/>          <xs:element name="BulkObservableList"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="type"                      type="bulkobservable-type-type" use="required"/>        <xs:attribute name="ext-type" type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="bulkobservable-type-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="asn"/>        <xs:enumeration value="atm"/>        <xs:enumeration value="e-mail"/>        <xs:enumeration value="ipv4-addr"/>        <xs:enumeration value="ipv4-net"/>        <xs:enumeration value="ipv4-net-mask"/>        <xs:enumeration value="ipv6-addr"/>        <xs:enumeration value="ipv6-net"/>Danyliw                      Standards Track                  [Page 154]

RFC 7970                     IODEF Version 2               November 2016        <xs:enumeration value="ipv6-net-mask"/>        <xs:enumeration value="mac"/>        <xs:enumeration value="site-uri"/>        <xs:enumeration value="domain-name"/>        <xs:enumeration value="domain-to-ipv4"/>        <xs:enumeration value="domain-to-ipv6"/>        <xs:enumeration value="domain-to-ipv4-timestamp"/>        <xs:enumeration value="domain-to-ipv6-timestamp"/>        <xs:enumeration value="ipv4-port"/>        <xs:enumeration value="ipv6-port"/>        <xs:enumeration value="windows-reg-key"/>        <xs:enumeration value="file-hash"/>        <xs:enumeration value="email-x-mailer"/>        <xs:enumeration value="email-subject"/>        <xs:enumeration value="http-user-agent"/>        <xs:enumeration value="http-request-uri"/>        <xs:enumeration value="mutex"/>        <xs:enumeration value="file-path"/>        <xs:enumeration value="user-name"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="BulkObservableFormat">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:Hash" minOccurs="0"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="BulkObservableList" type="xs:string"/>    <xs:element name="IndicatorExpression">      <xs:complexType>        <xs:sequence maxOccurs="unbounded">          <xs:choice>            <xs:element ref="iodef:IndicatorExpression"/>            <xs:element ref="iodef:Observable"/>            <xs:element ref="iodef:ObservableReference"/>            <xs:element ref="iodef:IndicatorReference"/>          </xs:choice>          <xs:element ref="iodef:Confidence" minOccurs="0"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="operator"                      type="indicatorexpression-operator-type"                      use="optional" default="and"/>        <xs:attribute name="ext-operator"Danyliw                      Standards Track                  [Page 155]

RFC 7970                     IODEF Version 2               November 2016                      type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="indicatorexpression-operator-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="not"/>        <xs:enumeration value="and"/>        <xs:enumeration value="or"/>        <xs:enumeration value="xor"/>      </xs:restriction>    </xs:simpleType>    <xs:element name="ObservableReference">      <xs:complexType>        <xs:attribute name="uid-ref" type="xs:IDREF" use="required"/>      </xs:complexType>    </xs:element>    <xs:element name="IndicatorReference">      <xs:complexType>        <xs:attribute name="uid-ref" type="xs:IDREF" use="optional"/>        <xs:attribute name="euid-ref" type="xs:string" use="optional"/>        <xs:attribute name="version" type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:element name="AttackPhase">      <xs:complexType>        <xs:sequence>          <xs:element ref="iodef:AttackPhaseID"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:URL" maxOccurs="unbounded"/>          <xs:element ref="iodef:Description"                      minOccurs="0" maxOccurs="unbounded"/>          <xs:element ref="iodef:AdditionalData"                      minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>      </xs:complexType>    </xs:element>    <xs:element name="AttackPhaseID" type="xs:string"/>    <!--     ===================================================================     == Miscellaneous classes                                         ==     ===================================================================    -->    <xs:element name="AdditionalData" type="iodef:ExtensionType"/>    <xs:element name="Description" type="iodef:MLStringType"/>    <xs:element name="URL" type="xs:anyURI"/>Danyliw                      Standards Track                  [Page 156]

RFC 7970                     IODEF Version 2               November 2016    <!--     ===================================================================     == IODEF data types                                              ==     ===================================================================    -->    <xs:simpleType name="PositiveFloatType">      <xs:restriction base="xs:float">        <xs:minExclusive value="0"/>      </xs:restriction>    </xs:simpleType>    <xs:complexType name="MLStringType">      <xs:simpleContent>        <xs:extension base="xs:string">          <xs:attribute name="translation-id"                        type="xs:string" use="optional"/>          <xs:attribute ref="xml:lang"/>        </xs:extension>      </xs:simpleContent>    </xs:complexType>    <xs:simpleType name="PortlistType">      <xs:restriction base="xs:string">        <xs:pattern value="\d+(\-\d+)?(,\d+(\-\d+)?)*"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="TimezoneType">      <xs:restriction base="xs:string">        <xs:pattern         value="Z|[\+\-](0[0-9]|1[0-4]):[0-5][0-9]"/>      </xs:restriction>    </xs:simpleType>    <xs:complexType name="ExtensionType" mixed="true">      <xs:sequence>        <xs:any namespace="##any" processContents="lax"                minOccurs="0" maxOccurs="unbounded"/>      </xs:sequence>      <xs:attribute name="name" type="xs:string" use="optional"/>      <xs:attribute name="dtype"                    type="iodef:dtype-type" use="required"/>      <xs:attribute name="ext-dtype" type="xs:string" use="optional"/>      <xs:attribute name="meaning" type="xs:string" use="optional"/>      <xs:attribute name="formatid" type="xs:string" use="optional"/>      <xs:attribute name="restriction"                    type="iodef:restriction-type" use="optional"/>      <xs:attribute name="ext-restriction"                    type="xs:string" use="optional"/>      <xs:attribute name="observable-id" type="xs:ID" use="optional"/>    </xs:complexType>Danyliw                      Standards Track                  [Page 157]

RFC 7970                     IODEF Version 2               November 2016    <xs:complexType name="SoftwareType">      <xs:sequence>        <xs:element ref="iodef:SoftwareReference" minOccurs="0"/>        <xs:element ref="iodef:URL"                    minOccurs="0" maxOccurs="unbounded"/>        <xs:element ref="iodef:Description"                    minOccurs="0" maxOccurs="unbounded"/>      </xs:sequence>    </xs:complexType>    <xs:element name="SoftwareReference">      <xs:complexType>        <xs:sequence>          <xs:any namespace="##any" processContents="lax"                  minOccurs="0" maxOccurs="unbounded"/>        </xs:sequence>        <xs:attribute name="spec-name"                      type="softwarereference-spec-name-type"                      use="required"/>        <xs:attribute name="ext-spec-name"                      type="xs:string" use="optional"/>        <xs:attribute name="dtype"                      type="softwarereference-dtype-type"                      use="optional"/>        <xs:attribute name="ext-dtype" type="xs:string" use="optional"/>      </xs:complexType>    </xs:element>    <xs:simpleType name="softwarereference-spec-name-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="custom"/>        <xs:enumeration value="cpe"/>        <xs:enumeration value="swid"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="softwarereference-dtype-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="bytes"/>        <xs:enumeration value="integer"/>        <xs:enumeration value="real"/>        <xs:enumeration value="string"/>        <xs:enumeration value="xml"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <!--     ===================================================================     == Global attribute type declarations                            ==     ===================================================================Danyliw                      Standards Track                  [Page 158]

RFC 7970                     IODEF Version 2               November 2016    -->    <xs:simpleType name="yes-no-unknown-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="yes"/>        <xs:enumeration value="no"/>        <xs:enumeration value="unknown"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="restriction-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="default"/>        <xs:enumeration value="public"/>        <xs:enumeration value="partner"/>        <xs:enumeration value="need-to-know"/>        <xs:enumeration value="private"/>        <xs:enumeration value="white"/>        <xs:enumeration value="green"/>        <xs:enumeration value="amber"/>        <xs:enumeration value="red"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="severity-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="low"/>        <xs:enumeration value="medium"/>        <xs:enumeration value="high"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="duration-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="second"/>        <xs:enumeration value="minute"/>        <xs:enumeration value="hour"/>        <xs:enumeration value="day"/>        <xs:enumeration value="month"/>        <xs:enumeration value="quarter"/>        <xs:enumeration value="year"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="action-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="nothing"/>        <xs:enumeration value="contact-source-site"/>        <xs:enumeration value="contact-target-site"/>        <xs:enumeration value="contact-sender"/>        <xs:enumeration value="investigate"/>Danyliw                      Standards Track                  [Page 159]

RFC 7970                     IODEF Version 2               November 2016        <xs:enumeration value="block-host"/>        <xs:enumeration value="block-network"/>        <xs:enumeration value="block-port"/>        <xs:enumeration value="rate-limit-host"/>        <xs:enumeration value="rate-limit-network"/>        <xs:enumeration value="rate-limit-port"/>        <xs:enumeration value="redirect-traffic"/>        <xs:enumeration value="honeypot"/>        <xs:enumeration value="upgrade-software"/>        <xs:enumeration value="rebuild-asset"/>        <xs:enumeration value="harden-asset"/>        <xs:enumeration value="remediate-other"/>        <xs:enumeration value="status-triage"/>        <xs:enumeration value="status-new-info"/>        <xs:enumeration value="watch-and-report"/>        <xs:enumeration value="defined-coa"/>        <xs:enumeration value="other"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>    <xs:simpleType name="dtype-type">      <xs:restriction base="xs:NMTOKEN">        <xs:enumeration value="boolean"/>        <xs:enumeration value="byte"/>        <xs:enumeration value="bytes"/>        <xs:enumeration value="character"/>        <xs:enumeration value="date-time"/>        <xs:enumeration value="integer"/>        <xs:enumeration value="ntpstamp"/>        <xs:enumeration value="portlist"/>        <xs:enumeration value="real"/>        <xs:enumeration value="string"/>        <xs:enumeration value="file"/>        <xs:enumeration value="path"/>        <xs:enumeration value="frame"/>        <xs:enumeration value="packet"/>        <xs:enumeration value="ipv4-packet"/>        <xs:enumeration value="ipv6-packet"/>        <xs:enumeration value="url"/>        <xs:enumeration value="csv"/>        <xs:enumeration value="winreg"/>        <xs:enumeration value="xml"/>        <xs:enumeration value="ext-value"/>      </xs:restriction>    </xs:simpleType>  </xs:schema>Danyliw                      Standards Track                  [Page 160]

RFC 7970                     IODEF Version 2               November 20169.  Security Considerations   The IODEF data model does not directly introduce security or privacy   issues.  However, as the data encoded by the IODEF might be   considered sensitive by the parties exchanging it or by those   described by it, care needs to be taken to ensure appropriate   handling during the document construction, exchange, processing,   archiving, subsequent retrieval, and analysis.9.1.  Security   The underlying messaging format and protocol used to exchange   instances of the IODEF MUST provide appropriate guarantees of   confidentiality, integrity, and authenticity.  The use of a   standardized security protocol is encouraged.  The Real-time Inter-   network Defense (RID) protocol [RFC6545] and its associated transport   binding IODEF/RID over HTTP/TLS [RFC6546] provide such security.   An IODEF implementation may act on the data in the document.  These   actions might be explicitly requested in the document or the result   of analytical logic that triggered on data in the document.  For this   reason, care must be taken by IODEF implementations to properly   authenticate the sender and receiver of the document.  The sender   needs confidence that sensitive information and timely requests for   action are sent to the correct recipient.  The recipient may   interpret the contents of the document differently based on who sent   it or vary actions based on the sender.  While the sender of the   document may explicitly convey confidence in the data in a granular   way using the Confidence class, the recipient is free to ignore or   refine this information to make its own assessment.  Ambiguous   Confidence elements (where it is unclear to which of a set of other   elements the Confidence element relates) in a document MUST be   ignored by the recipient.   Certain classes may require out-of-band coordination to agree upon   their semantics (e.g., Confidence@rating="low" or DefinedCOA).  This   coordination MUST occur prior to operational data exchange to prevent   the incorrect interpretation of these select data elements.  When   parsing these data elements, implementations should validate, when   possible, that they conform to the agreed upon semantics.  These   semantics may need to be periodically reevaluated.   Executable content of various forms could be embedded into the IODEF   document directly or through an extension.  Implementation MUST   handle this content with care to prevent unintentional automated   execution.  The following classes are explicitly intended to   represent content that might be executable:Danyliw                      Standards Track                  [Page 161]

RFC 7970                     IODEF Version 2               November 2016   o  All classes of type iodef:ExtensionType and the RecordPattern      class can represent arbitrary binary strings such as legitimate      software programs or malware.   o  The EmailMessage and EmailBody classes can represent email      attachments that can contain arbitrary content.   o  The DetectionPattern class could specify a machine-readable      configuration that directs the execution of the corresponding      tool.   PerSection 4.3, IODEF implementations will need to periodically   consult the IANA registries specified inSection 10.2 to discover   newly registered enumerated attribute values.  These implementations   MUST communicate with IANA in a way that ensures the integrity of the   values and the authenticity of the source.  HTTPS over TLS   [RFC2818][RFC5246] provides such security.9.2.  Privacy   The IODEF contains numerous fields that are identifiers that could be   linked to an individual or organization.  IODEF documents may contain   sensitive information about these identified parties; repeated   document exchanges about the same and related parties may enable the   correlation of data about them.  Likewise, a party may report on   another to a third party without their knowledge.   When creating an IODEF document, careful consideration must be given   to what information is shared.  Personal identifiers and attributable   sensitive information should only be shared when necessary.   When exchanging documents, transport security MUST provide document-   level confidentiality.  XML element-level confidentiality can also be   provided by using [W3C.XMLENC].   In order to suggest data processing and handling guidelines of the   encoded information, the IODEF allows a document sender to convey a   privacy policy using the restriction attribute.  The various   instances of this attribute allow different data elements of the   document to be covered by dissimilar policies.  While flexible, it   must be stressed that this approach only serves as a guideline from   the sender, as the recipient is free to ignore it.   Although outside of the scope of an IODEF implementation, the   contents of IODEF documents and any derived analysis should be   archived with appropriate confidentiality controls.  Likewise, access   to retrieve and analyze this data should be restricted to authorized   users.Danyliw                      Standards Track                  [Page 162]

RFC 7970                     IODEF Version 2               November 201610.  IANA Considerations   This document registers a namespace, an XML schema, and a number of   registries that map to enumerated values defined in the data model.   It also defines an Expert Review process for IODEF-related XML   registry entries.10.1.  Namespace and Schema   This document uses URNs to describe an XML namespace and schema   conforming to a registry mechanism described in [RFC3688].   Registration for the IODEF namespace:   o  URI: urn:ietf:params:xml:ns:iodef-2.0   o  Registrant Contact: See the author in the "Author's Address"      section of this document.   o  XML: None.  Namespace URIs do not represent an XML specification.   Registration for the IODEF XML schema:   o  URI: urn:ietf:params:xml:schema:iodef-2.0   o  Registrant Contact: See the first author of the "Author's Address"      section of this document.   o  XML: SeeSection 8 of this document.10.2.  Enumerated Value Registries   This document creates 34 identically structured registries to be   managed by IANA:   o  Name of the parent registry: "Incident Object Description Exchange      Format v2 (IODEF)"   o  URL of the registry: <http://www.iana.org/assignments/iodef2>   o  Namespace format: A registry entry consists of:      *  Value.  A value for a given IODEF attribute.  It MUST conform         to the formatting specified by the IODEF ENUM data type which         is implemented as an "xs:NMTOKEN" type per Section 3.3.4 of         [W3C.SCHEMA.DTYPES].  The value SHOULD conform to the         convention specified inSection 5.2.Danyliw                      Standards Track                  [Page 163]

RFC 7970                     IODEF Version 2               November 2016      *  Description.  A short description of the enumerated value.      *  Reference.  An optional list of URIs to further describe the         value.   o  Allocation policy: Expert Review per [RFC5226].  This reviewer      will ensure that the requested registry entry conforms to the      prescribed formatting.  The reviewer will also ensure that the      entry is an appropriate value for the attribute per the      information model (Section 3).   The registries to be created are named in the "Registry Name" column   of Table 1.  Each registry is initially populated with values and   descriptions that come from an attribute specified in the IODEF   schema (Section 8) whose description is found in a sub-section of the   information model (Section 3).  The initial values for the Value and   Description fields of a given registry are listed in the "IV (Value)"   and "IV (Desc.)" columns, respectively.  The "IV (Value)" points to a   given schema type perSection 8.  Each enumerated value in the schema   gets a corresponding entry in a given registry.  The "IV (Desc.)"   points to a section in the text of this document that describes each   enumerated value.  The initial value of the Reference field of every   registry entry described below should be this document.Danyliw                      Standards Track                  [Page 164]

RFC 7970                     IODEF Version 2               November 2016   +-------------------------+-----------------------------+-----------+   |      Registry Name      |          IV (Value)         |     IV    |   |                         |                             |  (Desc.)  |   +-------------------------+-----------------------------+-----------+   |       Restriction       |    iodef-restriction-type   |   3.3.1   |   |                         |                             |           |   |     Incident-purpose    |    incident-purpose-type    |    3.2    |   |                         |                             |           |   |     Incident-status     |     incident-status-type    |    3.2    |   |                         |                             |           |   |       Contact-role      |      contact-role-type      |    3.9    |   |                         |                             |           |   |       Contact-type      |      contact-type-type      |    3.9    |   |                         |                             |           |   | RegistryHandle-registry |   registryhandle-registry-  |   3.9.1   |   |                         |             type            |           |   |                         |                             |           |   |    PostalAddress-type   |   postaladdress-type-type   |   3.9.2   |   |                         |                             |           |   |      Telephone-type     |     telephone-type-type     |   3.9.4   |   |                         |                             |           |   |        Email-type       |       email-type-type       |   3.9.3   |   |                         |                             |           |   |    Expectation-action   |         action-type         |    3.15   |   |                         |                             |           |   |     Discovery-source    |    discovery-source-type    |    3.10   |   |                         |                             |           |   |    SystemImpact-type    |    systemimpact-type-type   |   3.12.1  |   |                         |                             |           |   | BusinessImpact-severity |   businessimpact-severity-  |   3.12.2  |   |                         |             type            |           |   |                         |                             |           |   |   BusinessImpact-type   |   businessimpact-type-type  |   3.12.2  |   |                         |                             |           |   |    TimeImpact-metric    |    timeimpact-metric-type   |   3.12.3  |   |                         |                             |           |   |   TimeImpact-duration   |        duration-type        |   3.12.3  |   |                         |                             |           |   |    Confidence-rating    |    confidence-rating-type   |   3.12.5  |   |                         |                             |           |   |    NodeRole-category    |    noderole-category-type   |   3.18.2  |   |                         |                             |           |   |     System-category     |     system-category-type    |    3.17   |   |                         |                             |           |   |     System-ownership    |    system-ownership-type    |    3.17   |   |                         |                             |           |   |     Address-category    |    address-category-type    |   3.18.1  |   |                         |                             |           |Danyliw                      Standards Track                  [Page 165]

RFC 7970                     IODEF Version 2               November 2016   |       Counter-type      |      counter-type-type      |   3.18.3  |   |                         |                             |           |   |       Counter-unit      |      counter-unit-type      |   3.18.3  |   |                         |                             |           |   |    DomainData-system-   |  domaindata-system-status-  |    3.19   |   |          status         |             type            |           |   |                         |                             |           |   |    DomainData-domain-   |  domaindata-domain-status-  |    3.19   |   |          status         |             type            |           |   |                         |                             |           |   |    RecordPattern-type   |   recordpattern-type-type   |   3.22.2  |   |                         |                             |           |   |      RecordPattern-     |  recordpattern-offsetunit-  |   3.22.2  |   |        offsetunit       |             type            |           |   |                         |                             |           |   |    Key-registryaction   |   key-registryaction-type   |   3.23.1  |   |                         |                             |           |   |      HashData-scope     |     hashdata-scope-type     |    3.26   |   |                         |                             |           |   |   BulkObservable-type   |   bulkobservable-type-type  |  3.29.3.1 |   |                         |                             |           |   |   IndicatorExpression-  |     indicatorexpression-    |   3.29.4  |   |         operator        |        operator-type        |           |   |                         |                             |           |   |   ExtensionType-dtype   |          dtype-type         |    2.16   |   |                         |                             |           |   | SoftwareReference-spec- |  softwarereference-spec-id- |   2.15.1  |   |            id           |             type            |           |   |                         |                             |           |   | SoftwareReference-dtype |   softwarereference-dtype-  |   2.15.1  |   |                         |             type            |           |   +-------------------------+-----------------------------+-----------+                 Table 1: IANA Enumerated Value Registries10.3.  Expert Review of IODEF-Related XML Registry Entries   IODEF class extensions, perSection 5.2, could register their   namespaces and schemas with the IANA XML namespace ("ns" on   <http://www.iana.org/assignments/xml-registry/>) and schema   registries ("schema" on <http://www.iana.org/assignments/xml-registry/>) described in [RFC3688].  In addition to any reviews   required by IANA, changes to the XML "schema" registry for schema   names beginning with "urn:ietf:params:xml:schema:iodef" are subject   to an additional IODEF Expert Review [RFC5226] to ensure   compatibility with IODEF and other existing IODEF extensions.Danyliw                      Standards Track                  [Page 166]

RFC 7970                     IODEF Version 2               November 2016   The IODEF expert(s) for these reviews will be designated by the IETF   Security Area Directors.   This document obsoletes [RFC6685].11.  References11.1.  Normative References   [E.164]    ITU Telecommunication Standardization Sector, "The              International Public Telecommunication Numbering Plan",              ITU-T Recommendation E.164, November 2010.   [IANA.Media]              IANA, "Media Types",              <http://www.iana.org/assignments/media-types/>.   [IANA.Ports]              IANA, "Service Name and Transport Protocol Port Number              Registry", <http://www.iana.org/assignments/service-names-port-numbers/>.   [IANA.Protocols]              IANA, "Assigned Internet Protocol Numbers",              <http://www.iana.org/assignments/protocol-numbers/>.   [IEEE.POSIX]              IEEE, "Information Technology - Portable Operating System              Interface (POSIX) Base Specifications, Issue 7", IEEE              Std 1003.1-2001, DOI 10.1109/IEEESTD.2009.5393893,              September 2009.   [ISO19770] International Organization for Standardization,              "Information technology -- Software asset management --              Part 2: Software identification tag", ISO              Standard 19770-2:2015, October 2015.   [ISO4217]  International Organization for Standardization, "Codes for              the representation of currencies", ISO 4217:2015, 2015.   [NIST.CPE] Cheikes, B., Waltermire, D., and K. Scarfone, "Common              Platform Enumeration: Naming Specification Version 2.3",              NIST Interagency Report 7695, August 2011,              <http://csrc.nist.gov/publications/nistir/ir7695/NISTIR-7695-CPE-Naming.pdf>.Danyliw                      Standards Track                  [Page 167]

RFC 7970                     IODEF Version 2               November 2016   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119,              DOI 10.17487/RFC2119, March 1997,              <http://www.rfc-editor.org/info/rfc2119>.   [RFC2781]  Hoffman, P. and F. Yergeau, "UTF-16, an encoding of ISO              10646",RFC 2781, DOI 10.17487/RFC2781, February 2000,              <http://www.rfc-editor.org/info/rfc2781>.   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO              10646", STD 63,RFC 3629, DOI 10.17487/RFC3629, November              2003, <http://www.rfc-editor.org/info/rfc3629>.   [RFC3688]  Mealling, M., "The IETF XML Registry",BCP 81,RFC 3688,              DOI 10.17487/RFC3688, January 2004,              <http://www.rfc-editor.org/info/rfc3688>.   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform              Resource Identifier (URI): Generic Syntax", STD 66,RFC 3986, DOI 10.17487/RFC3986, January 2005,              <http://www.rfc-editor.org/info/rfc3986>.   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing              Architecture",RFC 4291, DOI 10.17487/RFC4291, February              2006, <http://www.rfc-editor.org/info/rfc4291>.   [RFC4519]  Sciberras, A., Ed., "Lightweight Directory Access Protocol              (LDAP): Schema for User Applications",RFC 4519,              DOI 10.17487/RFC4519, June 2006,              <http://www.rfc-editor.org/info/rfc4519>.   [RFC5322]  Resnick, P., Ed., "Internet Message Format",RFC 5322,              DOI 10.17487/RFC5322, October 2008,              <http://www.rfc-editor.org/info/rfc5322>.   [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying              Languages",BCP 47,RFC 5646, DOI 10.17487/RFC5646,              September 2009, <http://www.rfc-editor.org/info/rfc5646>.   [RFC5952]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6              Address Text Representation",RFC 5952,              DOI 10.17487/RFC5952, August 2010,              <http://www.rfc-editor.org/info/rfc5952>.   [RFC6531]  Yao, J. and W. Mao, "SMTP Extension for Internationalized              Email",RFC 6531, DOI 10.17487/RFC6531, February 2012,              <http://www.rfc-editor.org/info/rfc6531>.Danyliw                      Standards Track                  [Page 168]

RFC 7970                     IODEF Version 2               November 2016   [RFC7203]  Takahashi, T., Landfield, K., and Y. Kadobayashi, "An              Incident Object Description Exchange Format (IODEF)              Extension for Structured Cybersecurity Information",RFC 7203, DOI 10.17487/RFC7203, April 2014,              <http://www.rfc-editor.org/info/rfc7203>.   [RFC7495]  Montville, A. and D. Black, "Enumeration Reference Format              for the Incident Object Description Exchange Format              (IODEF)",RFC 7495, DOI 10.17487/RFC7495, March 2015,              <http://www.rfc-editor.org/info/rfc7495>.   [W3C.SCHEMA]              Thompson, H., Beech, D., Maloney, M., and N. Mendelsohn,              "XML Schema Part 1: Structures Second Edition", W3C              Recommendation REC-xmlschema-1-20041028, October 2004,              <http://www.w3.org/TR/xmlschema-1/>.   [W3C.SCHEMA.DTYPES]              Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes              Second Edition", W3C Recommendation REC-xmlschema-              2-20041028, October 2004,              <http://www.w3.org/TR/xmlschema-2/>.   [W3C.XML]  Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and              F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth              Edition)", W3C Recommendation REC-xml-20081126, November              2008, <http://www.w3.org/TR/2008/REC-xml-20081126/>.   [W3C.XMLNS]              Bray, T., Hollander, D., Layman, A., Tobin, R., and H.              Thompson, "Namespaces in XML 1.0 (Third Edition)", W3C              Recommendation REC-xml-names-20091208, December 2009,              <http://www.w3.org/TR/2009/REC-xml-names-20091208/>.   [W3C.XMLSIG]              Eastlake, D., Reagle, J., Solo, D., Hirsch, F., and T.              Roessler, "XML Signature Syntax and Processing (Second              Edition)", W3C Recommendation REC-xmldsig-core-20080610,              June 2008, <http://www.w3.org/TR/xmldsig-core/>.   [W3C.XPATH]              Robie, J., Dyck, M., and J. Spiegel, "XML Path Language              (XPath) 3.1", W3C Candidate Recommendation CR-xpath-              31-20151217, December 2015,              <https://www.w3.org/TR/xpath-3/>.Danyliw                      Standards Track                  [Page 169]

RFC 7970                     IODEF Version 2               November 201611.2.  Informative References   [KB310516] Microsoft Corporation, "How to add, modify, or delete              registry subkeys and values by using a .reg file",              September 2013,              <https://support.microsoft.com/en-us/kb/310516>.   [NIST800.61rev2]              National Institute of Standards and Technology, "Computer              Security Incident Handling Guide", NIST Special              Publication 800-61, Revision 2, August 2012,              <http://dx.doi.org/10.6028/NIST.SP.800-61r2>.   [RFC2818]  Rescorla, E., "HTTP Over TLS",RFC 2818,              DOI 10.17487/RFC2818, May 2000,              <http://www.rfc-editor.org/info/rfc2818>.   [RFC3982]  Newton, A. and M. Sanz, "IRIS: A Domain Registry (dreg)              Type for the Internet Registry Information Service              (IRIS)",RFC 3982, DOI 10.17487/RFC3982, January 2005,              <http://www.rfc-editor.org/info/rfc3982>.   [RFC4180]  Shafranovich, Y., "Common Format and MIME Type for Comma-              Separated Values (CSV) Files",RFC 4180,              DOI 10.17487/RFC4180, October 2005,              <http://www.rfc-editor.org/info/rfc4180>.   [RFC5070]  Danyliw, R., Meijer, J., and Y. Demchenko, "The Incident              Object Description Exchange Format",RFC 5070,              DOI 10.17487/RFC5070, December 2007,              <http://www.rfc-editor.org/info/rfc5070>.   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an              IANA Considerations Section in RFCs",BCP 26,RFC 5226,              DOI 10.17487/RFC5226, May 2008,              <http://www.rfc-editor.org/info/rfc5226>.   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security              (TLS) Protocol Version 1.2",RFC 5246,              DOI 10.17487/RFC5246, August 2008,              <http://www.rfc-editor.org/info/rfc5246>.   [RFC5901]  Cain, P. and D. Jevans, "Extensions to the IODEF-Document              Class for Reporting Phishing",RFC 5901,              DOI 10.17487/RFC5901, July 2010,              <http://www.rfc-editor.org/info/rfc5901>.Danyliw                      Standards Track                  [Page 170]

RFC 7970                     IODEF Version 2               November 2016   [RFC6545]  Moriarty, K., "Real-time Inter-network Defense (RID)",RFC 6545, DOI 10.17487/RFC6545, April 2012,              <http://www.rfc-editor.org/info/rfc6545>.   [RFC6546]  Trammell, B., "Transport of Real-time Inter-network              Defense (RID) Messages over HTTP/TLS",RFC 6546,              DOI 10.17487/RFC6546, April 2012,              <http://www.rfc-editor.org/info/rfc6546>.   [RFC6685]  Trammell, B., "Expert Review for Incident Object              Description Exchange Format (IODEF) Extensions in IANA XML              Registry",RFC 6685, DOI 10.17487/RFC6685, July 2012,              <http://www.rfc-editor.org/info/rfc6685>.   [W3C.XMLENC]              Eastlake, D., Reagle, J., Solo, D., Hirsch, F., Nystrom,              M., Roessler, T., and K. Yiu, "XML Encryption Syntax and              Processing Version 1.1", W3C Recommendation REC-xmldsig-              core1-20130411, April 2013,              <https://www.w3.org/TR/xmlenc-core1/>.Acknowledgments   Thanks to Paul Stoecker for his editorial leadership in the   transition of an early draft to the current document.   Thanks to Kathleen Moriarty, Brian Trammel, Alexey Melnikov, Takeshi   Takahashi, David Waltermire, and Sean Turner (as the MILE working   group chairs, secretary, and area directors) for providing feedback   and coordination of this document.   Thanks to the following individuals (listed alphabetically) who   provided feedback during the meetings, on the mailing list, or   through implementation experience: Jerome Athias, David Black, Eric   Burger, Toma Cejka, Patrick Curry, John Field, Christopher   Harrington, Chris Inacio, Panos Kampanakis, David Misell, Daisuke   Miyamoto, Adam Montville, Robert Moskowitz, Lagadec Philippe, Tony   Rutkowski, Mio Suzuki, and Nik Teague.Danyliw                      Standards Track                  [Page 171]

RFC 7970                     IODEF Version 2               November 2016Author's Address   Roman Danyliw   CERT   Software Engineering Institute   Carnegie Mellon University   4500 Fifth Avenue   Pittsburgh, PA   United States of America   Email: rdd@cert.orgDanyliw                      Standards Track                  [Page 172]

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