Invoke-Obfuscation STDIN+ Launcher — Sigma Rule

Rule metadata and linked tags

Author: Jonathan Cheong, oscd.community. Source status: test; severity: high. Source dates: 2020-10-15 / 2024-04-15.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: b906bbac20e5987144deae763c33e62d4f125ccf469b17714bca21c7f0e79025

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: Invoke-Obfuscation STDIN+ Launcher
id: 6c96fc76-0eb1-11eb-adc1-0242ac120002
status: test
description: Detects Obfuscated use of stdin to execute PowerShell
references:
    - https://github.com/SigmaHQ/sigma/issues/1009  # (Task 25)
author: Jonathan Cheong, oscd.community
date: 2020-10-15
modified: 2024-04-15
tags:
    - attack.stealth
    - attack.t1027
    - attack.execution
    - attack.t1059.001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        # Example 1: c:\windows\sYstEm32\CmD.eXE /C"echO\Invoke-Expression (New-Object Net.WebClient).DownloadString | POwersHELl -NoEXiT -"
        # Example 2: c:\WiNDOws\sysTEm32\cmd.EXe /C " ECHo Invoke-Expression (New-Object Net.WebClient).DownloadString | POwersHELl -nol ${EXEcUtIONCONTeXT}.INvOkEComMANd.InvOKEScRIPt( $InpUt )"
        CommandLine|re: 'cmd.{0,5}(?:/c|/r).+powershell.+(?:\$\{?input\}?|noexit).+\"'
    condition: selection
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/SigmaHQ/sigma/issues/1009