Uncommon Child Process Of AddinUtil.EXE — Sigma Rule

Rule metadata and linked tags

Author: Michael McKinley (@McKinleyMike), Tony Latteri (@TheLatteri). Source status: test; severity: medium. Source dates: 2023-09-18 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 1eda5ac620ba88b72ef853afa35852479ba4547b55779f3e9a39c8a57b6ec2a3

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: Uncommon Child Process Of AddinUtil.EXE
id: b5746143-59d6-4603-8d06-acbd60e166ee
status: test
description: |
    Detects uncommon child processes of the Add-In deployment cache updating utility (AddInutil.exe) which could be a sign of potential abuse of the binary to proxy execution via a custom Addins.Store payload.
references:
    - https://www.blue-prints.blog/content/blog/posts/lolbin/addinutil-lolbas.html
author: Michael McKinley (@McKinleyMike), Tony Latteri (@TheLatteri)
date: 2023-09-18
tags:
    - attack.stealth
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\addinutil.exe'
    filter_main_werfault:
        Image|endswith:
            - ':\Windows\System32\conhost.exe'
            - ':\Windows\System32\werfault.exe'
            - ':\Windows\SysWOW64\werfault.exe'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.blue-prints.blog/content/blog/posts/lolbin/addinutil-lolbas.html