Format0 In Format0 we are given the following vulnerable code: #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]); } This is not really a format string vulnerability, our argument is going to be written in buffer with no size checks and buffer is just above target so we can overwrite it: