T1218.010: Regsvr32
| View on MITRE ATT&CK | T1218.010 |
|---|---|
| Tactic(s) | Defense Evasion |
Data from MITRE ATT&CK®:
Adversaries may abuse Regsvr32.exe to proxy execution of malicious code. Regsvr32.exe is a command-line program used to register and unregister object linking and embedding controls, including dynamic link libraries (DLLs), on Windows systems. The Regsvr32.exe binary may also be signed by Microsoft. (Citation: Microsoft Regsvr32)
Malicious usage of Regsvr32.exe may avoid triggering security tools that may not monitor execution of, and modules loaded by, the regsvr32.exe process because of allowlists or false positives from Windows using regsvr32.exe for normal operations. Regsvr32.exe can also be used to specifically bypass application control using functionality to load COM scriptlets to execute DLLs under user permissions. Since Regsvr32.exe is network and proxy aware, the scripts can be loaded by passing a uniform resource locator (URL) to file on an external Web server as an argument during invocation. This method makes no changes to the Registry as the COM object is not actually registered, only executed. (Citation: LOLBAS Regsvr32) This variation of the technique is often referred to as a "Squiblydoo" and has been used in campaigns targeting governments. (Citation: Carbon Black Squiblydoo Apr 2016) (Citation: FireEye Regsvr32 Targeting Mongolian Gov)
Regsvr32.exe can also be leveraged to register a COM Object used to establish persistence via Component Object Model Hijacking. (Citation: Carbon Black Squiblydoo Apr 2016)
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Cyber Threat Graph Context
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Reporting on this Technique
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Mitigations for this technique
MITRE ATT&CK Mitigations
How to detect this technique
MITRE ATT&CK Data Components
Module Load (Module)
Attaching a module into the memory of a process/program, typically to access shared resources/features provided by the module (ex: Sysmon EID 7)Network Connection Creation (Network Traffic)
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)Command Execution (Command)
The execution of a line of text, potentially with arguments, created from program code (e.g. a cmdlet executed via powershell.exe, interactive commands like >dir, shell executions, etc. )Process Creation (Process)
The initial construction of an executable managed by the OS, that may involve one or more tasks or threads. (e.g. Win EID 4688, Sysmon EID 1, cmd.exe > net use, etc.)Control Validation Tests for this Technique
Use Atomic Red Team tests to test your defenses against this technique.
Sigma Detections for this Technique
Suspicious HH.EXE Execution
Suspicious WmiPrvSE Child Process
Scripting/CommandLine Process Spawned Regsvr32
Network Connection Initiated By Regsvr32.EXE
Potentially Suspicious Regsvr32 HTTP/FTP Pattern
Suspicious Regsvr32 Execution From Remote Share
HTML Help HH.EXE Suspicious Child Process
Suspicious WMIC Execution Via Office Process
Potentially Suspicious Regsvr32 HTTP IP Pattern
DNS Query Request By Regsvr32.EXE
Potentially Suspicious Child Process Of Regsvr32
Regsvr32 Execution From Highly Suspicious Location
Potential Regsvr32 Commandline Flag Anomaly
Regsvr32 DLL Execution With Suspicious File Extension
Suspicious Microsoft Office Child Process
Unsigned DLL Loaded by Windows Utility
Regsvr32 Execution From Potential Suspicious Location
SP800-53 Controls
See which controls can help protect against this MITRE ATT&CK technique. This is based on mappings to associated SP800-53 controls produced by the MITRE Engenuity Center for Threat-Informed Defense.