Windows Registry COM Hijacking via TreatAs Subkey in CLSID
Alerts on registry modifications to HKU\Classes\CLSID\*\TreatAs that may indicate COM object hijacking/persistence.
- Product
- windows
- Category
- registry_set
- Author
- Kutepov Anton, oscd.community (SigmaHQ), DRL 1.1
- Published
- 2019-10-23
- Updated
- 2026-07-30
ATT&CK techniques
Persistence → Priv EscRecon
Resource Dev
Initial Access
Execution
Persistence
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule flags Windows Registry entries under HKU\Classes\CLSID\*\TreatAs, which can indicate COM object hijacking. Attackers can use TreatAs subkeys to redirect COM activation to attacker-controlled classes, supporting persistence and potential privilege escalation. It relies on registry set telemetry capturing the TargetObject path that contains HKU\, Classes\CLSID\, and \TreatAs, while excluding events associated with svchost.exe.
Reporting behind it
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
title: Windows Registry COM Hijacking via TreatAs Subkey in CLSID
id: 06116f51-b133-4420-8869-2eec46527a2d
status: test
description: This rule flags Windows Registry entries under HKU\Classes\CLSID\*\TreatAs, which can indicate COM object hijacking. Attackers can use TreatAs subkeys to redirect COM activation to attacker-controlled classes, supporting persistence and potential privilege escalation. It relies on registry set telemetry capturing the TargetObject path that contains HKU\, Classes\CLSID\, and \TreatAs, while excluding events associated with svchost.exe.
references:
- https://bohops.com/2018/08/18/abusing-the-com-registry-structure-part-2-loading-techniques-for-evasion-and-persistence/
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_persistence_com_key_linking.yml
author: Kutepov Anton, oscd.community, Huntrule Team
date: 2019-10-23
modified: 2025-10-26
tags:
- attack.privilege-escalation
- attack.persistence
- attack.t1546.015
logsource:
category: registry_set
product: windows
detection:
selection:
TargetObject|contains|all:
- HKU\
- Classes\CLSID\
- \TreatAs
filter_main_svchost:
Image: C:\WINDOWS\system32\svchost.exe
condition: selection and not 1 of filter_main_*
falsepositives:
- Maybe some system utilities in rare cases use linking keys for backward compatibility
level: medium
regression_tests_path: regression_data/rules/windows/registry/registry_set/registry_set_persistence_com_key_linking/info.yml
simulation:
- type: atomic-red-team
name: COM hijacking via TreatAs
technique: T1546.015
atomic_guid: 33eacead-f117-4863-8eb0-5c6304fbfaa9
license: DRL-1.1
related:
- id: 9b0f8a61-91b2-464f-aceb-0527e0a45020
type: derived