Automation · API / MCP 中文

Technique note · T1121

Regsvcs/Regasm

Regsvcs and Regasm are Windows command-line utilities that are used to register .NET Component Object Model (COM) assemblies. Both are digitally signed by Microsoft. Adversaries can use Regsvcs and Regasm to proxy execution of code through a trusted Windows utility. Both utilities may be used to bypass process whitelisting through use of attributes within the binary to specify code that should be run before registration or unregistration: <code>[ComRegisterFunction]</code> or <code>[ComUnregisterFunction]</code> respectively. The code with the registration and unregistration attributes will be executed even if the process is run under insufficient privileges and fails to execute.

ATT&CK T1121 platforms — Status Active Version 20.1

Regsvcs and Regasm are Windows command-line utilities that are used to register .NET Component Object Model (COM) assemblies. Both are digitally signed by Microsoft. 1 2 Adversaries can use Regsvcs and Regasm to proxy execution of code through a trusted Windows utility. Both utilities may be used to bypass process whitelisting through use of attributes within the binary to specify code that should be run before registration or unregistration: <code>[ComRegisterFunction]</code> or <code>[ComUnregisterFunction]</code> respectively. The code with the registration and unregistration attributes will be executed even if the process is run under insufficient privileges and fails to execute. 34

  1. MSDN Regsvcs
  2. MSDN Regasm
  3. LOLBAS Regsvcs
  4. LOLBAS Regasm

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