Sub-technique of T1546 Event Triggered Execution.View on attack.mitre.org
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 AppInit_DLLs value in the Registry keys HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows or HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows 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.
Rules on DetectionCode tagged with T1546.010.
| Rule | Level | Log source |
|---|---|---|
| New DLL Added to AppInit_DLLs Registry Key | medium | windows / registry_event |
None recorded.
| Used by | Procedure example |
|---|---|
| GroupAPT39 | APT39 has used malware to set |
| Used by | Procedure example |
|---|---|
| MalwareCherry Picker | Some variants of Cherry Picker use AppInit_DLLs to achieve persistence by creating the following Registry key: |
| MalwareRamsay | Ramsay can insert itself into the address space of other applications using the AppInit DLL Registry key. |
| MalwareT9000 | If a victim meets certain criteria, T9000 uses the AppInit_DLL functionality to achieve persistence by ensuring that every user mode process that is spawned will load its malicious DLL, ResN32.dll. It does this by creating the following Registry keys: |
Data from MITRE ATT&CK® (Enterprise). ATT&CK® is a registered trademark of The MITRE Corporation.
