CTF-All-In-One/doc/6.1.6_pwn_defconctf2015_fuckup.md

# 6.1.6 pwn DefconCTF2015 fuckup

- [ret2vdso 原理](#ret2vdso-原理)
- [题目解析](#题目解析)
- [Exploit](#exploit)
- [参考资料](#参考资料)


[下载文件](../src/writeup/6.1.6_pwn_defconctf2015_fuckup)

## ret2vdso 原理
在你使用 `ldd` 命令时，通常会显示出 vDSO，如下：
```
$ ldd /usr/bin/ls
        linux-vdso.so.1 (0x00007ffff7ffa000)
        libcap.so.2 => /usr/lib/libcap.so.2 (0x00007ffff79b2000)
        libc.so.6 => /usr/lib/libc.so.6 (0x00007ffff75fa000)
        /lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2 (0x00007ffff7dd8000)
```
32 位程序则会显示 `linux-gate.so.1`，都是一个意思。


## 题目解析
```
$ file fuckup 
fuckup: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked, stripped
$ checksec -f fuckup 
RELRO           STACK CANARY      NX            PIE             RPATH      RUNPATH      FORTIFY  Fortified Fortifiable  FILE
No RELRO        No canary found   NX enabled    No PIE          No RPATH   No RUNPATH   No       0               0       fuckup
```

## Exploit
完整的 exp 如下：

## 参考资料
- `man vdso`
- [Return to VDSO using ELF Auxiliary Vectors](http://v0ids3curity.blogspot.in/2014/12/return-to-vdso-using-elf-auxiliary.html)