Renamed PAExec Execution — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), Jason Lynch. Source status: test; severity: high. Source dates: 2021-05-22 / 2024-11-23.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: e81cf6dff123b7c4336042ec4c3f5ece3ca34a7783cddf9e8642c5eb06ebfa4a

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: Renamed PAExec Execution
id: c4e49831-1496-40cf-8ce1-b53f942b02f9
related:
    - id: 7b0666ad-3e38-4e3d-9bab-78b06de85f7b
      type: obsolete
status: test
description: Detects execution of renamed version of PAExec. Often used by attackers
references:
    - https://www.poweradmin.com/paexec/
    - https://summit.fireeye.com/content/dam/fireeye-www/summit/cds-2018/presentations/cds18-technical-s05-att&cking-fin7.pdf
author: Florian Roth (Nextron Systems), Jason Lynch
date: 2021-05-22
modified: 2024-11-23
tags:
    - attack.stealth
    - attack.t1202
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        - Description: 'PAExec Application'
        - OriginalFileName: 'PAExec.exe'
        - Product|contains: 'PAExec'
        - Hashes|contains:
              - IMPHASH=11D40A7B7876288F919AB819CC2D9802
              - IMPHASH=6444f8a34e99b8f7d9647de66aabe516
              - IMPHASH=dfd6aa3f7b2b1035b76b718f1ddc689f
              - IMPHASH=1a6cca4d5460b1710a12dea39e4a592c
    filter_main_known_location:
        - Image|endswith: '\paexec.exe'
        - Image|startswith: 'C:\Windows\PAExec-'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Weird admins that rename their tools
    - Software companies that bundle PAExec with their software and rename it, so that it is less embarrassing
    - When executed with the "-s" flag. PAExec will copy itself to the "C:\Windows\" directory with a different name. Usually like this "PAExec-[XXXXX]-[ComputerName]"
level: high

Original YAML and metadata in JSON

False positives

• Weird admins that rename their tools
• Software companies that bundle PAExec with their software and rename it, so that it is less embarrassing
• When executed with the "-s" flag. PAExec will copy itself to the "C:\Windows\" directory with a different name. Usually like this "PAExec-[XXXXX]-[ComputerName]"

Source references

• https://www.poweradmin.com/paexec/
• https://summit.fireeye.com/content/dam/fireeye-www/summit/cds-2018/presentations/cds18-technical-s05-att&cking-fin7.pdf