Detect Component Object Model Hijacking in CrowdStrike LogScale
Adversaries may establish persistence by executing malicious content triggered by hijacked references to Component Object Model (COM) objects. COM is a system within Windows to enable interaction between software components through the operating system. References to various COM objects are stored in the Registry. Adversaries can use the COM system to insert malicious code that can be executed in place of legitimate software through hijacking the COM references and relationships as a means for persistence. Hijacking a COM object requires a change in the Windows Registry to replace a reference to a legitimate system component which may cause the execution of the adversary's code instead of the intended COM component.
MITRE ATT&CK
- Tactic
- Privilege Escalation Persistence
- Technique
- T1546 Event Triggered Execution
- Sub-technique
- T1546.015 Component Object Model Hijacking
- Canonical reference
- https://attack.mitre.org/techniques/T1546/015/
LogScale Detection Query
#event_simpleName=RegGenericValueUpdate OR #event_simpleName=RegBinaryValueUpdate OR #event_simpleName=RegStringValueUpdate
| TargetRegistryKey = /(?i)Classes\\CLSID\\\{[0-9A-Fa-f\-]+\}\\(InprocServer32|LocalServer32|InprocServer|LocalServer|TreatAs|ProgID)/
| is_hkcu := TargetRegistryKey = /(?i)(HKU\\|HKCU\\|Software\\Classes\\CLSID)/
| is_suspicious_payload := TargetRegistryValueData = /(?i)(appdata|\\temp\\|programdata|users\\public|powershell|cmd\.exe|wscript|cscript|mshta|rundll32|regsvr32)/
| is_system_path := TargetRegistryValueData = /(?i)(windows\\system32|syswow64|program files)/
| is_hkcu_non_system := if(is_hkcu = true AND is_system_path = false, true, false)
| match(is_suspicious_payload = true OR is_hkcu_non_system = true)
| clsid_guid := regex(TargetRegistryKey, /CLSID\\(\{[0-9A-Fa-f\-]+\})/)
| detection_type := if(is_suspicious_payload = true, "COM_SUSPICIOUS_PAYLOAD",
if(is_hkcu = true AND is_system_path = false, "COM_HKCU_NON_SYSTEM",
if(is_hkcu = true, "COM_HKCU_OVERRIDE", "COM_HKLM_MODIFICATION")))
| table([timestamp, ComputerName, UserName, detection_type, clsid_guid, TargetRegistryKey, TargetRegistryValueData, ImageFileName, CommandLine])
| sort(timestamp, order=desc)CrowdStrike LogScale detection for COM hijacking (T1546.015) using Falcon registry write events. Identifies CLSID server key modifications (InprocServer32, LocalServer32, TreatAs) with suspicious scripting engine payloads or HKCU overrides to non-system paths, with detection type classification.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate software updates that re-register COM components as part of patching workflows, particularly for Microsoft Office or Visual Studio components
- Endpoint management agents (SCCM client, Tanium) that modify COM registrations when deploying or repairing managed applications
- Security products that register monitoring or inspection COM hooks in non-standard paths as part of their protection mechanism
Other platforms for T1546.015
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1COM Hijack via HKCU InprocServer32
Expected signal: Sysmon Event ID 13: TargetObject=HKCU\SOFTWARE\Classes\CLSID\{BCDE0395-E52F-467C-8E3D-C4579291692E}\InprocServer32, Details=AppData path. IsHkcuOverride=true, IsNotSystemPath=true. Process creation for reg.exe.
- Test 2COM Hijack Targeting Explorer Shell Extension CLSID
Expected signal: Sysmon Event ID 13 for HKCU CLSID registration with Temp directory DLL path. The Temp path is the high-risk indicator.
- Test 3Enumerate COM Hijacking Opportunities
Expected signal: Process creation for powershell.exe with registry enumeration command. Read-only registry access to HKLM and HKCU CLSID trees. Output reveals count of potential hijacking candidates.
References (5)
- https://attack.mitre.org/techniques/T1546/015/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1546.015/T1546.015.md
- https://www.cyberbit.com/blog/endpoint-security/com-hijacking-windows-overlooked-security-vulnerability/
- https://bohops.com/2018/08/18/abusing-the-com-registry-structure-part-2-loading-techniques-for-evasion-and-persistence/
- https://threatexpress.com/blogs/2021/02/living-off-the-com-land/
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