VPX — Void Packed Executable

Custom executable packer with all UPX fingerprints stripped. Same compression, same speed, same format support — zero UPX signatures in the output. Packs ELF, PE (Windows EXE/DLL), Mach-O, and DOS binaries.

What changed from stock UPX

What	Stock UPX	VPX (default)
Magic bytes	UPX! (0x21585055)	m30w (0x7730336D)
PE sections	UPX0 UPX1 UPX2	M3W0 M3W1 M3W2
$Info / $Id strings	Embedded in every packed binary	Gone
Copyright / URLs / author names	Embedded	Gone
Stub error messages	UPX-5.0 wants...	m3w-5.0 wants...
CLI branding	UPX	m30w

Custom Magic (configure_magic.py)

Optionally rebrand the packer with any 4-character magic word. Changes all magic bytes, section names, stub identifiers, and CLI branding — then rebuilds.

# Configure + build in one step
python3 configure_magic.py Fl4N --build

# Just configure (no build)
python3 configure_magic.py d00m

# Show current magic
python3 configure_magic.py --show

Any 4 ASCII characters. The default m30w works out of the box — only use this if you need a unique signature per deployment.

Magic	Sections	Example
m30w	M3W0/1/2	Default
Fl4N	FLN0/1/2	Custom build
d00m	D0M0/1/2	Custom build
XpLt	XPT0/1/2	Custom build

What gets patched:

• src/conf.h — magic constants
• src/pefile.cpp — PE section names
• src/help.cpp — CLI branding
• Stub headers and platform includes

Builds are statically linked by default.

Build

git clone --recurse-submodules https://github.com/Syn2Much.git
cd vpx

# Option 1: configure magic + build in one step
python3 configure_magic.py XpLt --build

# Option 2: manual build
mkdir -p build/release && cd build/release
cmake ../.. -DCMAKE_BUILD_TYPE=Release -DCMAKE_EXE_LINKER_FLAGS="-static"
cmake --build . --parallel

Requires: cmake 3.13+, C++17 compiler (gcc 8+ or clang 5+)

Usage

# Pack (LZMA — best compression)
./VPX --lzma ./binary

# Pack (best available method)
./VPX --best ./binary

# Try all methods (slow but tightest)
./VPX --brute ./binary

# Decompress
./VPX -d ./binary

# List info
./VPX -l ./binary

# Test integrity
./VPX -t ./binary

# Verify no UPX fingerprint
strings ./binary | grep -i upx
# ^ returns nothing

Supported Formats

Platform	Format	Arch	Status
Linux	linux/elf	x86, x86_64, ARM, MIPS, MIPSEL, PowerPC	OK
Windows	win32/pe	x86 (EXE, DLL)	OK
Windows	win64/pe	x86_64	Upstream stub bug
macOS	macho	x86, x86_64, ARM, ARM64, PowerPC, FAT	Untested
BSD	bsd/elf	x86	Untested
DOS	dos/exe	8086+	Untested

Proof

=== stock UPX packed binary ===
$ strings packed | grep -i upx
UPX!
$Info: This file is packed with the UPX executable packer http://upx.sf.net $
$Id: UPX 5.12 Copyright (C) 1996-2026 the UPX Team. All Rights Reserved. $

=== VPX packed binary ===
$ strings packed | grep -i upx
(nothing)

License

GPLv2+. See COPYING and LICENSE.

Based on UPX by Markus Oberhumer, Laszlo Molnar & John Reiser.