Detection rules › Sigma
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.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Defense Impairment | No specific technique |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 14 | RegistryEvent (Key and Value Rename) |
Rule body yaml
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-impairment
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
Stages and Predicates
Stage 0: condition
selection and not 1 of filter_main_*Stage 1: selection
selection:
TargetObject|contains: 'shellex\ContextMenuHandlers\EPP'
Stage 2: not filter_main_defender
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'
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
Image | starts_with | C:\Program Files (x86)\Windows Defender\ |
Image | starts_with | C:\Program Files\Windows Defender\ |
Image | starts_with | C:\ProgramData\Microsoft\Windows Defender\Platform\ |
Image | ends_with | \MsMpEng.exe |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
TargetObject | match |
|