Detectionhightest
Potential Persistence Via Microsoft Office Add-In
Detects potential persistence activity via startup add-ins that load when Microsoft Office starts (.wll/.xll are simply .dll fit for Word or Excel).
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Log Source
WindowsFile Event
ProductWindows← raw: windows
CategoryFile Event← raw: file_event
Events for file system activity including creation, modification, and deletion.
Detection Logic
Detection Logic4 selectors
detection:
selection_wlldropped:
TargetFilename|contains: '\Microsoft\Word\Startup\'
TargetFilename|endswith: '.wll'
selection_xlldropped:
TargetFilename|contains: '\Microsoft\Excel\Startup\'
TargetFilename|endswith: '.xll'
selection_xladropped:
TargetFilename|contains: 'Microsoft\Excel\XLSTART\'
TargetFilename|endswith: '.xlam'
selection_generic:
TargetFilename|contains: '\Microsoft\Addins\'
TargetFilename|endswith:
- '.xlam'
- '.xla'
- '.ppam'
condition: 1 of selection_*False Positives
Legitimate add-ins
References
MITRE ATT&CK
Tactics
Sub-techniques
Rule Metadata
Rule ID
8e1cb247-6cf6-42fa-b440-3f27d57e9936
Status
test
Level
high
Type
Detection
Created
Mon May 11
Modified
Wed Feb 08
Author
Path
rules/windows/file/file_event/file_event_win_office_addin_persistence.yml
Raw Tags
attack.persistenceattack.t1137.006