Shellcode Factory tool

A tool to print and test shellcodes from assembly code.

It supports both Gas and Intel syntax (.s and .asm extensions respectively), as well as x86 and x64 architectures.

Usage:

make targets [parameters]

build / assembly - will compile the assembly code from shellcode.s
debug - debugs the assembly binary
print / xxd / p - will print the shellcode in hex
x / auto / a - will run the shellcode using a smashed stack
sc_debug - will debug the shellcode called from a smashed stack
set - will let you edit the source assembly code
neg - will negate the shellcode, and prepend to it a 12-bytes-long decoder. It assumes the shellcode is reached right after a ret instruction
xor_byte - will xor the shellcode with a random byte, and prepend to it an appropriate decoder (the decoder is 21-26 bytes long). It will try to avoid the bytes from the NO parameter.
xor - will xor the shellcode with a random rotating word, and prepend to it an appropriate decoder (the decoder is 27-34 bytes long). It will try to avoid the bytes from the NO parameter.
alphanumeric - will transform the shellcode into one using alphanumeric chars only (it needs to be reached right after a ret instruction for it to work)
clean / c - removes generated files

ARCH=XX (default=32) XX-bit binaries (32 / 64)
S=filename (default=shellcode.s) Source assembly filename.
SC="\x31\xc0..." (ignored by default) Raw Input shellcode (overrides S parameter).
NO="[0x...]" (default="[0x00, 0x20, 0x9, 0xa]") List of chars to avoid when xor-ing
PAUSE=NO Disables the pause-before-execution security
LANG=C Changes the formatting of the print command to use a C-style array of bytes
SYNTAX=INTEL Changes the syntax used to display assembly source code

make print S=foo.asm SYNTAX=INTEL will print the shellcode from foo.asm with INTEL syntax
make S=foo.s set c p x ARCH=64 will let you edit foo.s and will then hexdump it and attempt to run it (x64)
make c print SC="\x31\xc0\x40\xcd\x80" will parse input shellcode into assembly instructions
make c p sc_debug SC="\x31\xc0\x40\xcd\x80" will clean (recommended) then print and debug input shellcode
make p S=foo.asm | grep -e x00 -e x20 is a useful trick to check for forbidden bytes (bytes 0x00 and 0x20 for instance)
make p xor S=foo.asm NO="[0x00, 0x20]" xors the shellcode to avoid forbidden bytes
make p alphanumeric S=foo.s generates an alphanumeric version of the shellcode

gcc (as frontend) and nasm for GAS and INTEL syntax respectively (extensions .s and .asm)
gdb (I also recommend enhancing it with peda: https://github.com/longld/peda)
python (tested with 2.7.12)
cut
objdump (optional: you can set OBJDUMP to DISABLED in the Makefile)
ndisasm (optional: only needed when SYNTAX=INTEL)
nano (optional: set and put targets only, and you can replace the EDITOR=... line in the Makefile by your own editor)
pandoc & lynx (optional) : print a nicer help/usage message
GNU make of course