Detect Component Object Model Hijacking in Elastic Security
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/
Elastic Detection Query
registry where event.type in ("creation", "change") and
registry.path : (
"HKU\\*\\SOFTWARE\\Classes\\CLSID\\*\\InprocServer32",
"HKU\\*\\SOFTWARE\\Classes\\CLSID\\*\\LocalServer32",
"HKU\\*\\SOFTWARE\\Classes\\CLSID\\*\\InprocServer",
"HKU\\*\\SOFTWARE\\Classes\\CLSID\\*\\LocalServer",
"HKU\\*\\SOFTWARE\\Classes\\CLSID\\*\\TreatAs",
"HKU\\*\\SOFTWARE\\Classes\\CLSID\\*\\ProgID",
"HKCU\\SOFTWARE\\Classes\\CLSID\\*\\InprocServer32",
"HKCU\\SOFTWARE\\Classes\\CLSID\\*\\LocalServer32",
"HKCU\\SOFTWARE\\Classes\\CLSID\\*\\InprocServer",
"HKCU\\SOFTWARE\\Classes\\CLSID\\*\\LocalServer",
"HKCU\\SOFTWARE\\Classes\\CLSID\\*\\TreatAs",
"HKCU\\SOFTWARE\\Classes\\CLSID\\*\\ProgID",
"HKLM\\SOFTWARE\\Classes\\CLSID\\*\\InprocServer32",
"HKLM\\SOFTWARE\\Classes\\CLSID\\*\\LocalServer32"
) and
(
registry.data.strings : (
"*AppData*", "*\\Temp\\*", "*ProgramData*", "*Users\\Public*",
"*powershell*", "*cmd.exe*", "*wscript*", "*cscript*",
"*mshta*", "*rundll32*", "*regsvr32*"
) or
(
registry.path : ("HKU\\*\\SOFTWARE\\Classes\\CLSID*", "HKCU\\SOFTWARE\\Classes\\CLSID*") and
not registry.data.strings : (
"*C:\\Windows\\system32\\*",
"*C:\\Windows\\SysWOW64\\*",
"*C:\\Program Files\\*",
"*C:\\Program Files (x86)\\*"
)
)
)Detects COM object hijacking via registry modifications to CLSID server keys (InprocServer32, LocalServer32, TreatAs, ProgID) in HKCU or HKLM. Flags suspicious payload paths (AppData, Temp, scripting engines) or user-hive overrides pointing to non-system paths, indicating persistence via COM hijacking (T1546.015).
Data Sources
Required Tables
False Positives & Tuning
- Legitimate software installation that registers COM components in user-space HKCU paths (e.g., per-user Office add-ins or browser extensions)
- Developer tools or IDEs that register test COM objects in AppData during development workflows
- Automation frameworks like AutoHotkey or scripting tools that legitimately register COM servers pointing to script hosts
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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