Invoke-Obfuscation Via Use Rundll32 - PowerShell — Sigma Rule

Rule metadata and linked tags

Author: Nikita Nazarov, oscd.community. Source status: test; severity: high. Source dates: 2019-10-08 / 2022-11-29.

{
  "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: d2c41a962d67604788543cf044989d1130beaeb62db892f55cda0ed0f700acc9

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 Via Use Rundll32 - PowerShell
id: a5a30a6e-75ca-4233-8b8c-42e0f2037d3b
status: test
description: Detects Obfuscated Powershell via use Rundll32 in Scripts
references:
    - https://github.com/SigmaHQ/sigma/issues/1009
author: Nikita Nazarov, oscd.community
date: 2019-10-08
modified: 2022-11-29
tags:
    - attack.stealth
    - attack.t1027
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_4104:
        ScriptBlockText|contains|all:
            - '&&'
            - 'rundll32'
            - 'shell32.dll'
            - 'shellexec_rundll'
        ScriptBlockText|contains:
            - 'value'
            - 'invoke'
            - 'comspec'
            - 'iex'
    condition: selection_4104
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

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