Suspicious COM Hijacking through TreatAs (via registry_set)

title: Suspicious COM Hijacking through TreatAs (via registry_set)
id: bbae153f-d8a1-5548-89fe-cf528e5f79b6
status: stable
description: This rule detects modification of TreatAs key to enable "rundll32.exe -sta" command
references:
    - https://attack.mitre.org/techniques/T1546/015/
    - https://github.com/redcanaryco/atomic-red-team/blob/40b77d63808dd4f4eafb83949805636735a1fd15/atomics/T1546.015/T1546.015.md
    - https://www.youtube.com/watch?v=3gz1QmiMhss&t=1251s
author: Huntrule Team
date: 2026-05-15
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|endswith: 'TreatAs\(Default)'
    filter_office:
        Image|startswith: 'C:\Program Files\Common Files\Microsoft Shared\ClickToRun\'
        Image|endswith: '\OfficeClickToRun.exe'
    filter_office2:
        Image:
            - 'C:\Program Files\Microsoft Office\root\integration\integrator.exe'
            - 'C:\Program Files (x86)\Microsoft Office\root\integration\integrator.exe'
    filter_svchost:
        Image: 'C:\Windows\system32\svchost.exe'
    filter_misexec:
        Image:
            - 'C:\Windows\system32\msiexec.exe'
            - 'C:\Windows\SysWOW64\msiexec.exe'
    condition: selection and not 1 of filter_*
falsepositives:
    - Unknown
level: medium