Sigma rule: Windows Defender Context Menu Removed

Rule

Title

Windows Defender Context Menu Removed

Status

experimental

Level

high

Author

Matt Anderson (Huntress)

Date

2025-07-09

File

rules/windows/process_creation/proc_creation_win_defender_remove_context_menu.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the use of reg.exe or PowerShell to delete the Windows Defender context menu handler registry keys.
This action removes the "Scan with Microsoft Defender" option from the right-click menu for files, directories, and drives.
Attackers may use this technique to hinder manual, on-demand scans and reduce the visibility of the security product.

Log source

product

windows

category

process_creation

Detection

selection_img:
    - Image|endswith:
          - '\powershell_ise.exe'
          - '\powershell.exe'
          - '\pwsh.exe'
          - '\reg.exe'
    - OriginalFileName:
          - 'powershell_ise.EXE'
          - 'PowerShell.EXE'
          - 'pwsh.dll'
          - 'reg.exe'
selection_action:
    CommandLine|contains:
        - 'del'
        - 'Remove-Item'
        - 'ri '
selection_reg_path:
    CommandLine|contains: '\shellex\ContextMenuHandlers\EPP'
condition: all of selection_*

False positives (as the rule lists them)

• May be part of a system customization or "debloating" script, but this is highly unusual in a managed corporate environment.

Tags

• attack.defense-impairment
• attack.t1685

MITRE ATT&CK ids this rule names

• T1685

Related rules

• 72a0369a-2576-4aaf-bfc9-6bb24a574ac6 (similar)

References

• https://research.splunk.com/endpoint/395ed5fe-ad13-4366-9405-a228427bdd91/
• https://winaero.com/how-to-delete-scan-with-windows-defender-from-context-menu-in-windows-10/
• https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/
• https://blog.malwarebytes.com/malwarebytes-news/2021/02/lazyscripter-from-empire-to-double-rat/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_defender_remove_context_menu.yml