Detection rules › Sigma
Windows AMSI Related Registry Tampering Via CommandLine
Detects tampering of AMSI (Anti-Malware Scan Interface) related registry values via command line tools such as reg.exe or PowerShell. AMSI provides a generic interface for applications and services to integrate with antimalware products. Adversaries may disable AMSI to evade detection of malicious scripts and code execution.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Defense Impairment | T1685 Disable or Modify Tools |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
Rule body yaml
title: Windows AMSI Related Registry Tampering Via CommandLine
id: 7dbbcac2-57a0-45ac-b306-ff30a8bd2981
related:
- id: aa37cbb0-da36-42cb-a90f-fdf216fc7467 # AMSI Disabled via Registry Modification
type: similar
status: experimental
description: |
Detects tampering of AMSI (Anti-Malware Scan Interface) related registry values via command line tools such as reg.exe or PowerShell.
AMSI provides a generic interface for applications and services to integrate with antimalware products.
Adversaries may disable AMSI to evade detection of malicious scripts and code execution.
references:
- https://github.com/arttoolkit/arttoolkit.github.io/blob/16d6230d009e58fd6f773f5317fd4d14c1f26004/_wadcoms/AMSI-Bypass-Jscript_amsienable.md
- https://mostafayahiax.medium.com/hunting-for-amsi-bypassing-methods-9886dda0bf9d
- https://www.mdsec.co.uk/2019/02/macros-and-more-with-sharpshooter-v2-0/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-12-25
tags:
- attack.defense-impairment
- attack.t1685
logsource:
category: process_creation
product: windows
detection:
selection_key:
CommandLine|contains|all:
- '\Software\Microsoft\Windows Script\Settings'
- 'AmsiEnable'
selection_reg_img:
- Image|endswith: '\reg.exe'
- OriginalFileName: 'reg.exe'
selection_reg_cmd:
CommandLine|contains: 'add'
selection_powershell_img:
- Image|endswith:
- '\powershell.exe'
- '\pwsh.exe'
- OriginalFileName:
- 'PowerShell.EXE'
- 'pwsh.dll'
selection_powershell_cmd:
CommandLine|contains:
- 'Set-ItemProperty'
- 'New-ItemProperty'
- 'sp '
condition: selection_key and (all of selection_powershell_* or all of selection_reg_*)
falsepositives:
- Unknown
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_amsi_registry_tampering/info.yml
simulation:
- type: atomic-red-team
name: AMSI Bypass - Create AMSIEnable Reg Key
technique: T1562.001
atomic_guid: 728eca7b-0444-4f6f-ac36-437e3d751dc0
Stages and Predicates
Stage 0: condition
selection_key and (all of selection_powershell_* or all of selection_reg_*)Stage 1: selection_key
selection_key:
CommandLine|contains|all:
- '\Software\Microsoft\Windows Script\Settings'
- 'AmsiEnable'
Stage 2: selection_powershell_img
selection_powershell_img:
- Image|endswith:
- '\powershell.exe'
- '\pwsh.exe'
- OriginalFileName:
- 'PowerShell.EXE'
- 'pwsh.dll'
Stage 3: selection_powershell_cmd
selection_powershell_cmd:
CommandLine|contains:
- 'Set-ItemProperty'
- 'New-ItemProperty'
- 'sp '
Stage 4: selection_reg_img
selection_reg_img:
- Image|endswith: '\reg.exe'
- OriginalFileName: 'reg.exe'
Stage 5: selection_reg_cmd
selection_reg_cmd:
CommandLine|contains: 'add'
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 |
|---|---|---|
CommandLine | match |
|
Image | ends_with |
|
OriginalFileName | eq |
|