sigmamediumHunting

Delete Defender Scan ShellEx Context Menu Registry Key

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.

Detection Query

selection:
  TargetObject|contains: shellex\ContextMenuHandlers\EPP
filter_main_defender:
  Image|startswith:
    - C:\ProgramData\Microsoft\Windows Defender\Platform\
    - C:\Program Files\Windows Defender\
    - C:\Program Files (x86)\Windows Defender\
  Image|endswith: \MsMpEng.exe
condition: selection and not 1 of filter_main_*

Author

Matt Anderson (Huntress)

Created

2025-07-11

Data Sources

windowsRegistry Delete Events

Platforms

windows

References

Tags

attack.defense-evasion

Raw Content

title: Delete Defender Scan ShellEx Context Menu Registry Key
id: 72a0369a-2576-4aaf-bfc9-6bb24a574ac6
related:
    - id: b9e8c7d6-a5f4-4e3d-8b1a-9f0c8d7e6a5b
      type: similar
status: experimental
description: 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.
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/
author: 'Matt Anderson (Huntress)'
date: 2025-07-11
modified: 2025-10-07
tags:
    - attack.defense-evasion
logsource:
    category: registry_delete
    product: windows
detection:
    selection:
        TargetObject|contains: 'shellex\ContextMenuHandlers\EPP'
    filter_main_defender:
        Image|startswith:
            - 'C:\ProgramData\Microsoft\Windows Defender\Platform\'
            - 'C:\Program Files\Windows Defender\'
            - 'C:\Program Files (x86)\Windows Defender\'
        Image|endswith: '\MsMpEng.exe'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unlikely as this weakens defenses and normally would not be done even if using another AV.
level: medium