pyNtdllOverwrite - API Unhooking in Python

Overwrite ntdll.dll’s “.text” section using a clean version of the DLL using Python.

Repository: https://github.com/ricardojoserf/pyNtdllOverwrite

It can help to evade security measures that install API hooks such as EDRs.

The unhooked version of the DLL can be obtained from:

  • A DLL file already on disk - For example “C:\Windows\System32\ntdll.dll”.
  • The KnownDlls folder (“\KnownDlls\ntdll.dll”).
  • A process created in debug mode - Processes created in suspended or debug mode have a clean ntdll.dll.



From disk

Get the clean ntdll.dll from disk. You can specify a file path or use the default value “C:\Windows\System32\ntdll.dll”:

python pyNtdllOverwrite.py -o disk [-p PATH]

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From KnownDlls folder

Get the clean ntdll.dll from the KnownDlls folder:

python pyNtdllOverwrite.py -o knowndlls

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From a debug process

Get the clean ntdll.dll from a new process created with the DEBUG_PROCESS flag. You can specify a binary to create the process or use the default value “C:\Windows\System32\calc.exe”:

python pyNtdllOverwrite.py -o debugproc [-p PATH]

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Written on July 9, 2024