vuln.c

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

int main(int argc, char *argv[]) {
    char msg[1024];
    static int flag = 0;

    if (argc < 2) {
        printf("[*] Error: no argument specified.\n");
        return 1;
    }

    strcpy(msg, argv[1]);
    printf(msg);
    printf("\n\n[*] flag @ 0x%08x = %d 0x%08x\n", &flag, flag, flag);

    if (flag)
        printf("Rewrite successed!\n");
    else
        printf("Rewrite failed...\n");

    return 0;
}