The Backdoor Factory (BDF) – Patch Binaries With Shellcode

The Backdoor Factory or BDF is a tool which enables you to patch binaries with shellcode and continue normal execution exactly as the executable binary would have in its’ pre-patched state.

Some executables have built in protection, as such this tool will not work on all binaries. It is advisable that you test target binaries before deploying them to clients or using them in exercises.

There’s a couple of somewhat related tools you can also check out:

– peinjector – MITM PE File Injector
– PEiD – Detect PE Packers, Cryptors & Compilers

Features of Backdoor Factory

Overall BDF Features

The user can:

• Provide custom shellcode.
• Patch a directory of executables/dlls.
• Select x32 or x64 binaries to patch only.
• Include BDF is other python projects see pebin.py and elfbin.py

PE File Related Backdoor-Factory Features

• Can find all codecaves in an EXE/DLL.
• By default, clears the pointer to the PE certificate table, thereby unsigning a binary.
• Can inject shellcode into code caves or into a new section.
• Can find if a PE binary needs to run with elevated privileges.
• When selecting code caves, you can use the following commands:
  • Jump (j), for code cave jumping
  • Single (s), for patching all your shellcode into one cave
  • Append (a), for creating a code cave
  • Ignore (i or q), nevermind, ignore this binary
• Can ignore DLLs
• Import Table Patching
• AutoPatching (-m automtic)
• Onionduke (-m onionduke)

ELF Files Backdoor Feature

Extends 1000 bytes (in bytes) to the TEXT SEGMENT and injects shellcode into that section of code.

Mach-O Files

Pre-Text Section patching and signature removal

The Backdoor Factory Usage

You can download Backdoor Factory here:

the-backdoor-factory-3.4.2.zip

Or read more here.