unstub

A Python SteamStub DRM unpacker supporting x86 and x64 executables across multiple stub variants.

Supported Variants

Variant	Architecture
SteamStub 2.0	x86
SteamStub 2.1	x86
SteamStub 3.0	x86, x64
SteamStub 3.1	x86, x64

Requirements

• Python 3.8+
• No third-party dependencies required

Usage

python3 unstub.py <file> [options]

Options

Flag	Description
--keepbind	Keep the .bind section in the output
--keepstub	Keep the DOS stub (default: zeroed)
--dumppayload	Dump the stub payload to disk
--dumpdrmp	Dump SteamDRMP.dll to disk
--realign	Realign sections after .bind removal (default: off)
--recalcchecksum	Recalculate the PE checksum
--quiet	Suppress debug output

Examples

python3 unstub.py game.exe
python3 unstub.py game.exe --keepbind --dumppayload
python3 unstub.py game.exe --dumpdrmp --recalcchecksum

The unpacked file is written alongside the input as <filename>.unpacked.exe.

Project Structure

unstub.py                     # CLI entry point
unstub/
    crypto.py                 # XOR, XTEA, and AES-CBC crypto primitives
    pe.py                     # PE32/PE64 parser and builder
    base_unpacker.py          # Shared unpacking pipeline (v3.x)
    utils.py                  # Pattern matching, alignment, PE checksum
    x86.py                    # x86 instruction decoder
    unpackers/
        variant20.py          # SteamStub 2.0 unpacker
        variant21.py          # SteamStub 2.1 unpacker
        variant30.py          # SteamStub 3.0 unpacker
        variant31.py          # SteamStub 3.1 unpacker