Sigma rule: AMSI Bypass Pattern Assembly GetType

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-f52df8739a89, updated 2022-11-09T00:00:00.000Z.

Rule

Title
AMSI Bypass Pattern Assembly GetType
Status
test
Level
high
Author
Florian Roth (Nextron Systems)
Date
2022-11-09
File
rules/windows/powershell/powershell_script/posh_ps_amsi_bypass_pattern_nov22.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects code fragments found in small and obfuscated AMSI bypass PowerShell scripts

Log source

product
windows
category
ps_script
definition
Requirements: Script Block Logging must be enabled

Detection

selection:
    ScriptBlockText|contains|all:
        - '[Ref].Assembly.GetType'
        - 'SetValue($null,$true)'
        - 'NonPublic,Static'
condition: selection

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.defense-impairment
  • attack.t1685
  • 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/rules/windows/powershell/powershell_script/posh_ps_amsi_bypass_pattern_nov22.yml

Sources and licences

  • SigmaHQ

    "AMSI Bypass Pattern Assembly GetType" by Florian Roth (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/powershell/powershell_script/posh_ps_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: AMSI Bypass Pattern Assembly GetType",
entity page, dataset version ref-f52df8739a89, updated 2022-11-09T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/e0d6c087-2d1c-47fd-8799-3904103c5a98 (accessed 2026-11-03).
Underlying source: SigmaHQ rule e0d6c087-2d1c-47fd-8799-3904103c5a98, 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.