Buffer Overflow

It’s hard to explain further if we don’t know what you already know and what you want to learn. I’m sure you’ve already read that, but a buffer overflow happens when a variable will holds a content larger than it’s size in memory. In general it will make the program crash, but if the overflow is correctly done by the attacker, then it can executes what is call a shellcode, which corresponds to instructions written by the attacker.

This confirms what I read on the “La pile du programme” ^^ ‘
So it’s good I understood x)

It would be cool an article on it
On hackthis

In the meantime, for the French who read this post
Good Youtube and watch this LONG video

and

Buffer overflow:
You are allowed to use: x
But you can use: 2x
Because in 2x+1 the return address is written and if you overwrite it will make the program crush
Sou you nop x, write the shellcode on 2x, and write your new return address on 2x+1 so jumps to the NOP sled and executes the payload.

Maybe practicing can help you: http://overthewire.org/wargames/narnia/

One last thing, you don’t wanna always execute a shellcode, sometimes you just need to change the program flow, or to change a var ;p

Good luck and Happy Hacking