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.
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Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.
Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.
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_*)False positive likelihood has not been assessed. Additional context may be needed during triage.
Simulations
AMSI Bypass - Create AMSIEnable Reg Key
GUID: 728eca7b-0444-4f6f-ac36-437e3d751dc0