Windows Process Creation: Renamed PAExec Application Execution

Flags Windows executions of a renamed PAExec binary using process metadata and known IMPHASH values.

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windows-process-creation-renamed-paexec-application-execution-c4e49831

title: "Windows Process Creation: Renamed PAExec Application Execution"
id: b46c74f5-ac02-4d04-a595-c70cd9a5ba54
related:
  - id: 7b0666ad-3e38-4e3d-9bab-78b06de85f7b
    type: obsolete
  - id: c4e49831-1496-40cf-8ce1-b53f942b02f9
    type: derived
status: test
description: This rule identifies execution of a renamed PAExec binary by matching specific file metadata and multiple known import-hash (IMPHASH) values tied to PAExec. Renaming this utility is a common attacker tradecraft to reduce visibility and blend into legitimate administration tooling. It relies on Windows process creation telemetry, including process image path, file description, original filename, product string, and importer-hash values.
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
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_renamed_paexec.yml
author: Florian Roth (Nextron Systems), Jason Lynch, Huntrule Team
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
license: DRL-1.1

What it detects

This rule identifies execution of a renamed PAExec binary by matching specific file metadata and multiple known import-hash (IMPHASH) values tied to PAExec. Renaming this utility is a common attacker tradecraft to reduce visibility and blend into legitimate administration tooling. It relies on Windows process creation telemetry, including process image path, file description, original filename, product string, and importer-hash values.

Known 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]"

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.