CTF: pwn03

pwn03.c

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

int main()
{
  char pass[32];
  setvbuf(stdout, NULL, _IONBF, 0);
  setvbuf(stdin, NULL, _IONBF, 0);

  puts("Welcome to Pwn03!!!");
  puts("We removed /bin/sh");
  puts("for security reason.");
  puts("password? ");
  gets(pass);

  if(strcmp(pass, "watalab") == 0){
    puts("login success!!!");
    system("/usr/bin/uptime");
  }else{
    puts("login failed\n");
  }
}