Kali Linux - An Ethical Hacker's Cookbook - Second Edition

How to do it...

The following steps demonstrate the stack-based buffer overflow:

1. Let's take a look at another simple C program:

#include<stdio.h> 
#include<string.h> 
void main(int argc, char *argv[]) 
{ 
    char buf[120]; 
    strcpy(buf, argv[1]); 
    printf(buf); 
}  

This program uses a vulnerable strcpy() method. We save the program to a file.

2. Compile the program with gcc using fno-stack-protector and execstack:

gcc -ggdb name.c -o name -fno-stack-protector -z execstack

3. Turn off address space randomization using the following code:

echo 0 > /proc/sys/kernel/randomize_va_space

4. Open our program in gdb using the following command:

gdb ./name

The following screenshot shows the output of the preceding command:

5. We supply our input with Python using ...