Sideloading detection & monitor sideloader countermeasure

[kevoreilly]

No description provided.

[gemini-code-assist]

Hello @kevoreilly, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

Summary of Changes

This pull request introduces a mechanism to detect and counter DLL sideloading attacks. It adds functionality to identify potentially malicious DLLs within a directory by comparing them against known system DLLs. If sideloading is detected, the pull request implements a countermeasure by copying necessary DLLs (capemon.dll and version.dll) and a configuration file into the application's directory, effectively sideloading the monitoring DLLs instead of the potentially malicious ones. The changes primarily affect the analyzer/windows/lib/api/process.py file, with additions to the lib/common/constants.py file to define sideloading DLL names.

Highlights

• DLL Sideloading Detection: Implements a function detect_dll_sideloading to identify potential DLL sideloading attacks by comparing DLLs in a directory against known system DLLs.
• Sideloading Countermeasure: If sideloading is detected, the pull request copies capemon.dll, version.dll, and a configuration file into the application's directory to counter the attack.
• New Constants: Adds constants for the names of the 32-bit and 64-bit sideloader DLLs (SIDELOADER32_NAME and SIDELOADER64_NAME) in lib/common/constants.py.

Changelog

Click here to see the changelog

• analyzer/windows/lib/api/process.py
  • Added create_unicode_buffer and windll imports from ctypes.
  • Added SIDELOADER32_NAME and SIDELOADER64_NAME to the list of imported constants from lib.common.defines.
  • Added CSIDL constants for system directories.
  • Initialized self.path to None in the __init__ method.
  • Added get_folder_path method to retrieve system folder paths using SHGetFolderPathW.
  • Added detect_dll_sideloading method to detect potential DLL sideloading attacks.
  • Assigned the path variable to self.path in the execute method.
  • Modified the inject method to implement the sideloading countermeasure if DLL sideloading is detected.
  • Removed the ": %s" from the log message in the ttd_stop method.
  • Copied the capemon.dll, version.dll, and config.ini files to the application directory if sideloading is detected.
• analyzer/windows/lib/common/constants.py
  • Added constants SIDELOADER32_NAME and SIDELOADER64_NAME to define the names of the sideloader DLLs.

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---

A DLL,
a wolf in system's clothing,
fooled no more now.

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[gemini-code-assist]

Code Review

This pull request introduces DLL sideloading detection and a countermeasure to copy necessary DLLs to the application's directory. The changes look good overall, but there are a few areas that could be improved for clarity and robustness.

Summary of Findings

• Error Handling in detect_dll_sideloading: The detect_dll_sideloading function catches all exceptions. It would be better to catch specific exceptions to avoid masking unexpected errors.
• Redundant os.path.join calls: In the inject function, os.path.join is called multiple times with the same directory. This can be simplified.
• Missing Error Handling for File Copy Operations: The copy function in inject does not have error handling. If the copy fails, the analysis might proceed with missing DLLs.

Merge Readiness

The pull request introduces important functionality for detecting and mitigating DLL sideloading. However, the identified issues, particularly the broad exception handling and lack of error checking during file copy operations, should be addressed before merging to ensure the stability and reliability of the analysis. I am unable to approve this pull request, and others should review and approve this code before merging.