{"id":"e0d6c087-2d1c-47fd-8799-3904103c5a98","title":"AMSI Bypass Pattern Assembly GetType","description":"Detects code fragments found in small and obfuscated AMSI bypass PowerShell scripts","author":"Florian Roth (Nextron Systems)","status":"test","level":"high","date":"2022-11-09","modified":"","tags":["attack.defense-impairment","attack.t1685","attack.execution"],"technique_ids":["T1685"],"logsource":{"product":"windows","category":"ps_script","definition":"Requirements: Script Block Logging must be enabled"},"falsepositives":["Unknown"],"references":["https://www.mdsec.co.uk/2018/06/exploring-powershell-amsi-and-logging-evasion/","https://twitter.com/cyb3rops/status/1588574518057979905?s=20&t=A7hh93ONM7ni1Rj1jO5OaA"],"source_path":"rules/windows/powershell/powershell_script/posh_ps_amsi_bypass_pattern_nov22.yml","source_sha256":"db8c99ec1d92ccc85eb20937601127d60e14b5801c1d7ce31d246cb35e3d8f85","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/powershell/powershell_script/posh_ps_amsi_bypass_pattern_nov22.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: AMSI Bypass Pattern Assembly GetType\nid: e0d6c087-2d1c-47fd-8799-3904103c5a98\nstatus: test\ndescription: Detects code fragments found in small and obfuscated AMSI bypass PowerShell scripts\nreferences:\n    - https://www.mdsec.co.uk/2018/06/exploring-powershell-amsi-and-logging-evasion/\n    - https://twitter.com/cyb3rops/status/1588574518057979905?s=20&t=A7hh93ONM7ni1Rj1jO5OaA\nauthor: Florian Roth (Nextron Systems)\ndate: 2022-11-09\ntags:\n    - attack.defense-impairment\n    - attack.t1685\n    - attack.execution\nlogsource:\n    product: windows\n    category: ps_script\n    definition: 'Requirements: Script Block Logging must be enabled'\ndetection:\n    selection:\n        ScriptBlockText|contains|all:\n            - '[Ref].Assembly.GetType'\n            - 'SetValue($null,$true)'\n            - 'NonPublic,Static'\n    condition: selection\nfalsepositives:\n    - Unknown\nlevel: high\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1685","id":"T1685","name":"Disable or Modify Tools","page":"techniques/enterprise/T1685/"}],"data_path":"data/detection-rules/e0d6c087-2d1c-47fd-8799-3904103c5a98.json","kind":"sigma"}