Files
Print3M-shellcoder/shellcoder.py
T
2024-07-20 00:17:19 +02:00

108 lines
2.8 KiB
Python

#!/usr/bin/env python3
#
# Shellcoder.py :
#
# Author: Print3M (https://github.com/Print3M)
#
# This script helps automate the shellcode testing process.
# It takes an Assembly file with shellcode, compiles
# it into machine code (NASM), generates a payload in C with that,
# and pastes it into the loader C file. Finally, the prepared C file
# is compiled using MSVC. With this script you go from Assembly
# shellcode to executable file with one command!
#
# External dependencies:
# - Python 3
# - NASM (Netwide Assembler)
# - Visual Studio 2022
"""
[ ] Sprawdz czy zwykly shellcode dziala
[ ] Moze NASM trzeba jakos inaczej kompilowac / pobierac?
"""
import subprocess
import os
import sys
# Directory with output files
OUT_DIR = "out"
# Utility files
SHELLCODE_INPUT_FILE = "shellcode.asm"
SHELLCODE_OUTPUT_FILE = f"{OUT_DIR}\\shellcode.bin"
LOADER_INPUT_FILE = "loader.c"
LOADER_OUTPUT_FILE = f"{OUT_DIR}\\malware.c"
# String to be replaced by generated payload
PAYLOAD_STRING = ":PAYLOAD:"
# Name of final binary output file
BINARY_OUTPUT_FILE = f"{OUT_DIR}\\malware.exe"
# Batch script with Visual Studio compiler environment variables
MSVC_BATCH_SCRIPT = "C:\\Program Files\\Microsoft Visual Studio\\2022\\Community\\VC\\Auxiliary\\Build\\vcvars64.bat"
def is_cmd_available(cmd: str):
try:
subprocess.call(cmd, text=True)
except FileNotFoundError:
return False
return True
def assert_cmd(cmd: str):
if (is_cmd_available(cmd)):
return
print(f"[!] command not found: {cmd}", file=sys.stderr)
sys.exit(-1)
if __name__ == "__main__":
# Check if NASM is available
assert_cmd("nasm")
# Prepare output directory
os.makedirs(OUT_DIR, exist_ok=True)
# Compile Assembly
subprocess.run(
["nasm", "-f", "bin", SHELLCODE_INPUT_FILE, "-o", SHELLCODE_OUTPUT_FILE], check=True
)
print(f"[+] NASM: {SHELLCODE_INPUT_FILE} -> {SHELLCODE_OUTPUT_FILE}")
# Prepare C array with shellcode payload
payload = ""
with open(SHELLCODE_OUTPUT_FILE, "rb") as f:
bytes = bytearray(f.read())
size = len(bytes)
for byte in bytes:
payload += "\\" + hex(byte).lstrip("0")
print(f"[+] Payload size: {size} bytes")
# Inject payload into loader source code
with open(LOADER_INPUT_FILE, "r") as f:
loader = f.read()
loader = loader.replace(PAYLOAD_STRING, payload)
with open(LOADER_OUTPUT_FILE, "w") as f:
f.write(loader)
print(f"[+] {LOADER_INPUT_FILE} -> {LOADER_OUTPUT_FILE}")
# Compile final binary
print(f"[*] MSVC: Compilation of {LOADER_OUTPUT_FILE} \n")
cmd = f'"{MSVC_BATCH_SCRIPT}" && cd "{OUT_DIR}" && cl.exe "../{LOADER_OUTPUT_FILE}"'
proc = subprocess.run(cmd, check=True, text=True)
print(f"\n[+] Output binary ({BINARY_OUTPUT_FILE}) is ready to be executed!")