Adversaries may register malicious network provider dynamic link libraries (DLLs) to capture cleartext user credentials during the authentication process. Network provider DLLs allow Windows to interface with specific network protocols and can also support add-on credential management functions.[1] During the logon process, Winlogon (the interactive logon module) sends credentials to the localmpnotify.exe process via RPC. Thempnotify.exe process then shares the credentials in cleartext with registered credential managers when notifying that a logon event is happening.[2][3][4]
Adversaries can configure a malicious network provider DLL to receive credentials frommpnotify.exe.[5] Once installed as a credential manager (via the Registry), a malicious DLL can receive and save credentials each time a user logs onto a Windows workstation or domain via theNPLogonNotify() function.[4]
Adversaries may target planting malicious network provider DLLs on systems known to have increased logon activity and/or administrator logon activity, such as servers and domain controllers.[2]
| ID | Mitigation | Description |
|---|---|---|
| M1047 | Audit | Periodically review for new and unknown network provider DLLs within the Registry ( Ensure only valid network provider DLLs are registered. The name of these can be found in the Registry key at |
| M1028 | Operating System Configuration | Starting in Windows 11 22H2, the |
| M1024 | Restrict Registry Permissions | Restrict Registry permissions to disallow the modification of sensitive Registry keys such as |
| ID | Name | Analytic ID | Analytic Description |
|---|---|---|---|
| DET0580 | Detect Network Provider DLL Registration and Credential Capture | AN1598 | Detects registration of new or modified network provider DLLs via registry changes, anomalous file creation of DLLs in system directories, and suspicious process activity (mpnotify.exe interacting with non-standard DLLs). Multi-event correlation ties registry modification events to subsequent DLL loads during user logon activity. |