T1546.010

Description

Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppInit DLLs loaded into processes. Dynamic-link libraries (DLLs) that are specified in the <code>AppInit_DLLs</code> value in the Registry keys <code>HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows</code> or <code>HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows</code> are loaded by user32.dll into every process that loads user32.dll.

In practice this is nearly every program, since user32.dll is a very common library. Similar to Process Injection, these values can be abused to obtain elevated privileges by causing a malicious DLL to be loaded and run in the context of separate processes on the computer.

Malicious AppInit DLLs may also provide persistence by continuously being triggered by API activity. The AppInit DLL functionality is disabled in Windows 8 and later versions when secure boot is enabled.