T1137.002 Office Test

T1137.002 Office Test

Sub-technique of: T1137

High-Level Description

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.

There exist user and global Registry keys for the Office Test feature, such as:

• HKEY_CURRENT_USER\Software\Microsoft\Office test\Special\Perf
• HKEY_LOCAL_MACHINE\Software\Microsoft\Office test\Special\Perf

Adversaries 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.

Kill Chain Phase

• Persistence (TA0003)

Platforms: Windows, Office Suite

What to Check

• Identify if Office Test technique is applicable to target environment
• Check Windows systems for indicators of Office Test
• Check Office Suite systems for indicators of Office Test
• Verify mitigations are bypassed or absent (2 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Atomic Red Team Tests

The following tests are from Atomic Red Team and provide actionable ways to test this technique:

Atomic Test 1: Office Application Startup Test Persistence (HKCU)

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. Key is used for debugging purposes. Not created by default & exist in HKCU & HKLM hives.