The Stack6 challenge was definitely a learning experience for me. This actually went beyond my existing skills, and made me learn some new stuff.

We are given the following code.

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

void …

Wow, this challenge was a tough one for me. I ran into some huge problems that I had to work out. Considering this is a “standard buffer overflow”, I figured it’d be as easy as some of the others I’ve done in the past. I’ll explain my frustrations inline.

First, …

With this challenge, I think things really start to get fun, and more real-world.

We are provided with the following C program:

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

void win()
{
 printf("code flow successfully changed\n");
} …

This challenge starts getting a little bit more involved than the previous ones. Instead of just providing a new value for the “modified” variable, we need to make the code jump to a method, changing the execution.

#include <stdlib.h>
#include <unistd.h>
#include …

This challenge is pretty much the same as the previous challenge, except that the buffer comes from an environmental variable.

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

int main(int argc, char **argv)
{
 volatile int modified;
 char …

This challenge is very similar to the previous one. The main difference is that instead of just validating that the “modified” value was changed, it validates that it was changed to a specific value, 0x61626364, or “dcba” in ASCII.

#include <stdlib.h>
#include …