Delete Defender Scan ShellEx Context Menu Registry Key

calendar Apr 28, 2026 · attack.defense-impairment  ·
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Detects deletion of registry key that adds 'Scan with Defender' option in context menu. Attackers may use this to make it harder for users to scan files that are suspicious.

Sigma rule (View on GitHub)

 1title: Delete Defender Scan ShellEx Context Menu Registry Key
 2id: 72a0369a-2576-4aaf-bfc9-6bb24a574ac6
 3related:
 4    - id: b9e8c7d6-a5f4-4e3d-8b1a-9f0c8d7e6a5b
 5      type: similar
 6status: experimental
 7description: Detects deletion of registry key that adds 'Scan with Defender' option in context menu. Attackers may use this to make it harder for users to scan files that are suspicious.
 8references:
 9    - https://research.splunk.com/endpoint/395ed5fe-ad13-4366-9405-a228427bdd91/
10    - https://winaero.com/how-to-delete-scan-with-windows-defender-from-context-menu-in-windows-10/
11    - https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/
12    - https://blog.malwarebytes.com/malwarebytes-news/2021/02/lazyscripter-from-empire-to-double-rat/
13author: 'Matt Anderson (Huntress)'
14date: 2025-07-11
15modified: 2025-10-07
16tags:
17    - attack.defense-impairment
18logsource:
19    category: registry_delete
20    product: windows
21detection:
22    selection:
23        TargetObject|contains: 'shellex\ContextMenuHandlers\EPP'
24    filter_main_defender:
25        Image|startswith:
26            - 'C:\ProgramData\Microsoft\Windows Defender\Platform\'
27            - 'C:\Program Files\Windows Defender\'
28            - 'C:\Program Files (x86)\Windows Defender\'
29        Image|endswith: '\MsMpEng.exe'
30    condition: selection and not 1 of filter_main_*
31falsepositives:
32    - Unlikely as this weakens defenses and normally would not be done even if using another AV.
33level: medium

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