| ID | Name |
|---|---|
| T1137.001 | Office Template Macros |
| T1137.002 | Office Test |
| T1137.003 | Outlook Forms |
| T1137.004 | Outlook Home Page |
| T1137.005 | Outlook Rules |
| T1137.006 | Add-ins |
Adversaries may abuse the Microsoft Office "Office Test" Registry key to obtain persistence on a compromised system. An Office Test Registry location exists that allows a user to specify an arbitrary DLL that will be executed every time an Office application is started. This Registry key is thought to be used by Microsoft to load DLLs for testing and debugging purposes while developing Office applications. This Registry key is not created by default during an Office installation.[1][2]
There exist user and global Registry keys for the Office Test feature, such as:
HKEY_CURRENT_USER\Software\Microsoft\Office test\Special\PerfHKEY_LOCAL_MACHINE\Software\Microsoft\Office test\Special\PerfAdversaries may add this Registry key and specify a malicious DLL that will be executed whenever an Office application, such as Word or Excel, is started.
| ID | Name | Description |
|---|---|---|
| G0007 | APT28 |
APT28 has used the Office Test persistence mechanism within Microsoft Office by adding the Registry key |
| ID | Mitigation | Description |
|---|---|---|
| M1040 | Behavior Prevention on Endpoint |
On Windows 10, enable Attack Surface Reduction (ASR) rules to prevent Office applications from creating child processes and from writing potentially malicious executable content to disk. [3] |
| M1054 | Software Configuration |
Create the Registry key used to execute it and set the permissions to "Read Control" to prevent easy access to the key without administrator permissions or requiring Privilege Escalation.[2] |
| ID | Name | Analytic ID | Analytic Description |
|---|---|---|---|
| DET0315 | Detect Persistence via Office Test Registry DLL Injection | AN0880 |
Adversaries create the 'Office Test\Special\Perf' registry key and specify a malicious DLL path that is auto-loaded when an Office application starts. This DLL is injected into the Office process memory space and can provide persistent execution without requiring macro enablement. |
| AN0881 |
Office application auto-loads a non-standard DLL during startup triggered via Office Test Registry key, often without macro warning banners. DLL persistence mechanism circumvents traditional macro defenses. |