detection.wiki

Detection rules › Sigma

Removal Of AMSI Provider Registry Keys

Status
test
Severity
high
Log source
product windows, category registry_delete
Author
frack113
Source
github.com/SigmaHQ/sigma

Detects the deletion of AMSI provider registry key entries in HKLM\Software\Microsoft\AMSI. This technique could be used by an attacker in order to disable AMSI inspection.

MITRE ATT&CK coverage

TacticTechniques
Defense ImpairmentT1685 Disable or Modify Tools

Event coverage

ProviderEventTitle
SysmonEvent ID 14RegistryEvent (Key and Value Rename)

Rule body yaml

title: Removal Of AMSI Provider Registry Keys
id: 41d1058a-aea7-4952-9293-29eaaf516465
status: test
description: Detects the deletion of AMSI provider registry key entries in HKLM\Software\Microsoft\AMSI. This technique could be used by an attacker in order to disable AMSI inspection.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1562.001/T1562.001.md
    - https://seclists.org/fulldisclosure/2020/Mar/45
author: frack113
date: 2021-06-07
modified: 2025-10-07
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: windows
    category: registry_delete
detection:
    selection:
        TargetObject|endswith:
            - '{2781761E-28E0-4109-99FE-B9D127C57AFE}' # IOfficeAntiVirus
            - '{A7C452EF-8E9F-42EB-9F2B-245613CA0DC9}' # ProtectionManagement.dll
    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
level: high
regression_tests_path: regression_data/rules/windows/registry/registry_delete/registry_delete_removal_amsi_registry_key/info.yml
simulation:
    - type: atomic-red-team
      name: AMSI Bypass - Remove AMSI Provider Reg Key
      technique: T1562.001
      atomic_guid: 13f09b91-c953-438e-845b-b585e51cac9b

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_*

Stage 1: selection

selection:
    TargetObject|endswith:
        - '{2781761E-28E0-4109-99FE-B9D127C57AFE}'
        - '{A7C452EF-8E9F-42EB-9F2B-245613CA0DC9}'

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.

FieldKindExcluded values
Imagestarts_withC:\Program Files (x86)\Windows Defender\
Imagestarts_withC:\Program Files\Windows Defender\
Imagestarts_withC:\ProgramData\Microsoft\Windows Defender\Platform\
Imageends_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.

FieldKindValues
TargetObjectends_with
  • {2781761E-28E0-4109-99FE-B9D127C57AFE}
  • {A7C452EF-8E9F-42EB-9F2B-245613CA0DC9}