Query: actor TTPs: Credential API Hooking
Matching passage: T1056.004 Credential API Hooking. Tactics: collection, credential access. Description: Adversaries may hook into Windows application programming interface (API) functions and Linux system functions to collect user credentials. Malicious hooking mechanisms may capture API or function calls that include parameters that reveal user authentication credentials.(Citation: Microsoft TrojanSpy:Win32/Ursnif.gen!I Sept 2017) Unlike [Keylogging](https://attack.mitre.org/techniques/T1056/001), this technique focuses specifically on API functions that include parameters that reveal user credentials. In Windows, hooking involves redirecting calls to these functions and can be implemented via: * **Hooks procedures**, which intercept and execute designated code in response to events such as messages, keystrokes, and mouse inputs.(Citation: Microsoft Hook Overview)(Citation: Elastic Process Injection July 2017) * **Import address table (IAT) hooking**, which use modifications to a process’s IAT, where pointers to imported API functions are stored.(Citation: Elastic Process Injection July 2017)(Citation: Adlice Software IAT Hooks Oct 2014)(Citation: MWRInfoSecurity Dynamic Hooking 2015) * **Inline hooking**, which overwrites the first bytes in an API function to redirect code flow.(Citation: Elastic Process Injection July 2017)(Citation: HighTech Bridge Inline Hooking Sept 2011)(Citation: MWRInfoSecurity Dynamic Hooking 2015) In Linux and macOS, adversaries may hook into system functions via the `LD_PRELOAD` (Linux) or `DYLD_INSERT_LIBRARIES` (macOS) environment variables, which enables loading shared libraries into a program’s address space. For example, an adversary may capture credentials by hooking into the `libc read` function leveraged by SSH or SCP.(Citation: Intezer Symbiote 2022)
Near-miss passage: T1056.002 GUI Input Capture. Tactics: collection, credential access. Description: Adversaries may mimic common operating system GUI components to prompt users for credentials with a seemingly legitimate prompt. When programs are executed that need additional privileges than are present in the current user context, it is common for the operating system to prompt the user for proper credentials to authorize the elevated privileges for the task (ex: [Bypass User Account Control](https://attack.mitre.org/techniques/T1548/002)). Adversaries may mimic this functionality to prompt users for credentials with a seemingly legitimate prompt for a number of reasons that mimic normal usage, such as a fake installer requiring additional access or a fake malware removal suite.(Citation: OSX Malware Exploits MacKeeper) This type of prompt can be used to collect credentials via various languages such as [AppleScript](https://attack.mitre.org/techniques/T1059/002)(Citation: LogRhythm Do You Trust Oct 2014)(Citation: OSX Keydnap malware)(Citation: Spoofing credential dialogs) and [PowerShell](https://attack.mitre.org/techniques/T1059/001).(Citation: LogRhythm Do You Trust Oct 2014)(Citation: Enigma Phishing for Credentials Jan 2015)(Citation: Spoofing credential dialogs) On Linux systems adversaries may launch dialog boxes prompting users for credentials from malicious shell scripts or the command line (i.e. [Unix Shell](https://attack.mitre.org/techniques/T1059/004)).(Citation: Spoofing credential dialogs) Adversaries may also mimic common software authentication requests, such as those from browsers or email clients. This may also be paired with user activity monitoring (i.e., [Browser Information Discovery](https://attack.mitre.org/techniques/T1217) and/or [Application Window Discovery](https://attack.mitre.org/techniques/T1010)) to spoof prompts when users are naturally accessing sensitive sites/data.