Unusual Child Process Of AddinUtil.EXE (via process_creation)

title: Unusual Child Process Of AddinUtil.EXE (via process_creation)
id: 697a76a1-f001-5d2b-8700-58a03725e3dd
status: stable
description: This rule detects uncommon child processes of the Add-In deployment cache updating utility (AddInutil.exe) which could be a sign of potential misuse of the binary to proxy execution via a custom Addins.Store payload.
references:
    - https://attack.mitre.org/techniques/T1218/
    - https://www.blue-prints.blog/content/blog/posts/lolbin/addinutil-lolbas.html
author: Huntrule Team
date: 2026-05-05
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