| Android Debug Bridge | |
|---|---|
 | |
 Starting the adb server inGNOME Terminal, which thenenumerates the devices. After that, ashell is opened on the device being debugged to run theuname command. | |
| Original author | |
| Stable release | 34.0.1 (March 2023) |
| Repository | android.googlesource.com |
| Written in | C++ |
| Operating system | Windows, Linux, macOS |
| Included with | Android SDK |
| Type | Software development tool |
| License | Apache License 2.0 |
| Website | developer |
TheAndroid Debug Bridge (commonly abbreviated asadb) is aprogramming tool used for thedebugging ofAndroid-based devices. Thedaemon on the Android device connects with the server on the host PC overUSB orTCP, which connects to the client that is used by the end-user over TCP. Made available asopen-source software under theApache License byGoogle since 2007, its features include a shell and the possibility to make backups. The adb software is available forWindows,Linux andmacOS. It has been misused bybotnets and othermalware, for which mitigations were developed such asRSA authentication and devicewhitelisting.
Features of adb include copying files from the host computer,[1] installing apps, viewing logcat output, getting aUnix shell,[2] and rebooting intoQualcomm EDL mode.[3] For example, Androidapplications can be saved by the commandbackup to a file.[4] It also includes support for theJava Debug Wire Protocol.[5]
Somegraphical interfaces have been made available. The graphical Android Device Monitor inAndroid Studio can be used for retrieving information from an Android device.[6]
Android's method to install APK files on a device has been used as a way to sideload unofficial apps ontoWindows Subsystem for Android[7] and Chrome OS's Android virtual machine.[8]
Shizuku allows an Android phone to connect to its own ADB when connected to a wireless network. The application is available for free on the Google Play Store.[9]
TheAndroid Software Development Kit (SDK) was first released in 2007.[10] Since 2017, Google made it possible to download adb separately from the Android SDK.[11]
In 2015, Microsoft released an Android emulator that can connect to the adb client.[12] In 2016 forAndroid Studio 2.0 a 5x performance improvement was made for installing apps and pushing files through adb.[13] For easier usage ofAndroid Things, a wrapper was made in 2017 around manual adb commands.[14] For Android 11 in 2020, Google added adb incremental installations.[15] In 2020, Wi-Fi adb was integrated into Android Studio for macOS.[16] In 2021 forAndroid 12, theadb backup command was limited so that backing up user data from apps is opt-in using a per-app manifesto configuration[17] after being deprecated in Android 10 along withadb restore.[18]Fuchsia will be backwards-compatible with adb. It will be replaced with fx and ffx.[19]
For Windows, the Android SDK contains the adb.exe binary that can be extracted and installed.[20] How-To Geek recommends adding the folder containing the binaries to thePATH environment variable.[21]
OnUbuntu, adb can be installed with theandroid-tools-adb package.[22] ForDebian, it has been recommended to also install theandroid-sdk-platform-tools-common package next to theadb package, which installs theudev rules which makes it possible to run the tool withoutroot permissions.[23] For macOS and other Linux distributions, the platform tools can be downloaded and the PATH variable can be modified inbashrc.[24]
InAndroid 4.2.2 or later (API level 17), a dialog is shown with an RSAfingerprint that the user needs to accept. This protects against computers exploiting the debugging mechanism without consent of the device user.[25] Starting in Android 4.2, the developer settings are hidden by default. Pressing seven times on the build number in the about menu makes them visible to the user. After that, the USB debugging option can be enabled.[26] Some Android vendors have different procedures to enable it. For example, Huawei requires entering a pincode before adb can be enabled.
If thetouchscreen of an Android device is broken, it can be possible to connect a mouse to the device usingUSB On-The-Go and enable USB debugging.[27][28]
The adb protocol can be transported over USB or overWi-Fi throughTCP. It uses aclient-server architecture. There are two different protocols in use. The first is between the client and the server and the second is between the server and the daemon. The adb daemon is implemented inC and located in the Android user space. The daemon is facilitated by the Android USB framework,UsbDeviceManager andUsbDebuggingManager.[5]
The communication mode between the client and server is a TCP socket. The server listens on a port, to which the client has to send a request. The request contains a 4-byte initial field in ASCII and a payload. The payload starts with the word host, to indicate it should be sent to the server. The server can then reply with OKAY or FAIL to indicate the status, combined with an optional payload and length.[5]
The messages sent from the server consist of a 24-byte long header, with the following fields:[5]
0xFFFFFFFFUp toAndroid 2.2, Android was vulnerable to theRageAgainstTheCageexploit. The adbdaemon did not check for the return value of thesetuidsystem call whendropping privileges. The exploitforks processes until it fails due to the exhaustion ofprocess identifiers. When the daemon crashes and restarts, it cannot start a new process with dropped privileges and keeps running as root. Then adb provided a root shell.[29] In 2017, a security vulnerability was disclosed that exploited ADB to take over the onboardmodem. The attack required adb to be already enabled and authorized, although some workarounds were available.[30]
Various families of malware such as ADB.Miner, Ares, IPStorm, Fbot and Trinity have scanned the internet for public availability of the adb interface and installed malware on those devices.[31] adb can also be used to removemalware, by booting intosafe mode and running theadb uninstall command.[32]
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