Basic Linux Exploits: Moving towards exploits

Note: Hacking is not a joke so please keep patience and learn it step by step.

If you have read all our previous posts , you will be ready to exploits the system . So after cover all basics and necessary things it’s time to moving towards  exploits.  Lets start from Buffer-code overflows .
There is a basic question that what can buffer-overflow do in exploit , so lets see the power of buffer overflowshere.

So if you are ready to moving towards exploit ,lets start:
What are Buffers ?
Buffers are basically use to store data in memory. While we are moving towards buffers we are basically interested in special types of buffers , buffers that can store strings or say that can hold strings.

Problems with buffers

There is a basic problem with bufffers that the itself have no mechanism to handle exception i.e, putting to much data into the reserve place.
Lets see an Example:
Try to copy 25 characters in a character type array of size[5]
Look at the code:

#include
int main(int argc, char *argv[])
{
char buffer[5],k;
strcpy(buffer,argv[1]);
printf(“buffer =%s”,buffer);

return 0;
}

What just happens?
Output : segmentation fault
Look at the screenshot below

This is we did to crash whatsapp , we just passes a large string of special characters which it can’t handle and just start crashing repeatedly .

But it’s not the end of our exploit tutorial even it’s only the starting. As I said before “Hacking is not a joke so please keep patience and learn it step by step.” So please stick with us , in our next post we will show you by debugging it, and will tell you how to find it’s eip or rip(instruction pointer ,which will help us to make a jump for next instruction).