Bad Opsec Powershell Code Artifacts — Sigma Rule

Rule metadata and linked tags

Author: ok @securonix invrep_de, oscd.community. Source status: test; severity: critical. Source dates: 2020-10-09 / 2022-12-25.

{
  "product": "windows",
  "category": "ps_module",
  "definition": "0ad03ef1-f21b-4a79-8ce8-e6900c54b65b"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 2395f144cbf1f1e363e06404c539589f1c8d159e5a9a540638cd7b771d6f070d

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: Bad Opsec Powershell Code Artifacts
id: 8d31a8ce-46b5-4dd6-bdc3-680931f1db86
related:
    - id: 73e733cc-1ace-3212-a107-ff2523cc9fc3
      type: derived
status: test
description: |
    focuses on trivial artifacts observed in variants of prevalent offensive ps1 payloads, including
    Cobalt Strike Beacon, PoshC2, Powerview, Letmein, Empire, Powersploit, and other attack payloads
    that often undergo minimal changes by attackers due to bad opsec.
references:
    - https://newtonpaul.com/analysing-fileless-malware-cobalt-strike-beacon/
    - https://labs.sentinelone.com/top-tier-russian-organized-cybercrime-group-unveils-fileless-stealthy-powertrick-backdoor-for-high-value-targets/
    - https://www.mdeditor.tw/pl/pgRt
author: 'ok @securonix invrep_de, oscd.community'
date: 2020-10-09
modified: 2022-12-25
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: ps_module
    definition: 0ad03ef1-f21b-4a79-8ce8-e6900c54b65b
detection:
    selection_4103:
        Payload|contains:
            - '$DoIt'
            - 'harmj0y'
            - 'mattifestation'
            - '_RastaMouse'
            - 'tifkin_'
            - '0xdeadbeef'
    condition: selection_4103
falsepositives:
    - 'Moderate-to-low; Despite the shorter length/lower entropy for some of these, because of high specificity, fp appears to be fairly limited in many environments.'
level: critical

Original YAML and metadata in JSON

False positives

• Moderate-to-low; Despite the shorter length/lower entropy for some of these, because of high specificity, fp appears to be fairly limited in many environments.

Source references

• https://newtonpaul.com/analysing-fileless-malware-cobalt-strike-beacon/
• https://labs.sentinelone.com/top-tier-russian-organized-cybercrime-group-unveils-fileless-stealthy-powertrick-backdoor-for-high-value-targets/
• https://www.mdeditor.tw/pl/pgRt