Sigma rule: PowerShell AMSI Bypass Pattern

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-8705851a2e51, updated 2023-02-03T00:00:00.000Z.

SigmaHQ marks this rule as deprecated.

Rule

Title
PowerShell AMSI Bypass Pattern
Status
deprecated
Level
high
Author
@Kostastsale
Date
2022/11/04
Modified
2023/02/03
File
deprecated/windows/proc_creation_win_powershell_amsi_bypass_pattern_nov22.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects attempts to disable AMSI in the command line. It is possible to bypass AMSI by disabling it before loading the main payload.

Log source

product
windows
category
process_creation

Detection

selection1:
  Image|endswith:
    - '\powershell.exe'
    - '\pwsh.exe'
    - '\powershell_ise.exe'
  CommandLine|contains|all:
    - '[Ref].Assembly.GetType'
    - 'SetValue($null,$true)'
    - 'NonPublic,Static'
condition: selection1

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.defense_evasion
  • attack.t1562.001
  • attack.execution

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/deprecated/windows/proc_creation_win_powershell_amsi_bypass_pattern_nov22.yml

Sources and licences

  • SigmaHQ

    "PowerShell AMSI Bypass Pattern" by @Kostastsale (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/deprecated/windows/proc_creation_win_powershell_amsi_bypass_pattern_nov22.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: PowerShell AMSI Bypass Pattern",
entity page, dataset version ref-8705851a2e51, updated 2023-02-03T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/4f927692-68b5-4267-871b-073c45f4f6fe (accessed 2026-11-03).
Underlying source: SigmaHQ rule 4f927692-68b5-4267-871b-073c45f4f6fe, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.