Skip to main content

Protostar Format0

About

This level introduces format strings, and how attacker supplied format strings can modify the execution flow of programs.

Hints

  • This level should be done in less than 10 bytes of input.
  • “Exploiting format string vulnerabilities”

This level is at /opt/protostar/bin/format0

Source code

(format0.c) download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

void vuln(char *string)
{
  volatile int target;
  char buffer[64];

  target = 0;

  sprintf(buffer, string);
  
  if(target == 0xdeadbeef) {
      printf("you have hit the target correctly :)\n");
  }
}

int main(int argc, char **argv)
{
  vuln(argv[1]);
}