Suspicious Start-Process PassThru — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2022-01-15 / not supplied.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 8a4cae65d492035b01339f89309fcdedec48bbccb38ac35c0713ea65ed4ecf5f

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious Start-Process PassThru
id: 0718cd72-f316-4aa2-988f-838ea8533277
status: test
description: Powershell use PassThru option to start in background
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1036.003/T1036.003.md
    - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.management/Start-Process?view=powershell-5.1&viewFallbackFrom=powershell-7
author: frack113
date: 2022-01-15
tags:
    - attack.stealth
    - attack.t1036.003
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - Start-Process
            - '-PassThru '
            - '-FilePath '
    condition: selection
falsepositives:
    - Legitimate PowerShell scripts
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate PowerShell scripts

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1036.003/T1036.003.md
• https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.management/Start-Process?view=powershell-5.1&viewFallbackFrom=powershell-7