Module Objectives:

*What is a Buffer Overflow?
*Exploitation
*How to detect buffer overflows in a program?
*Skills Required
*CPU/OS Dependency
*Understanding Stacks
*Stack based Buffer Oveflows
*Technical details
*Writing your own exploits
*Defense Against Buffer Overflows


Note: This material WILL be on the Exam....

I would hate to be the one when the $%it rolled down hill over one keystroke error!   

Lesson continues from above....

Buffer Overflow vulnerabilities infest the IT (Information Technology duh...) environment more often than other vulnerabilites because it has little to do with security, inherently; the vulnerabilites occur mainly because of human error, which is difficult to detect, and not often anticipated in the first place.

Here's an example: Suppose you want to tell a co-worker something important. When you finally get the opportunity, you "zone out", and forget wehat it is you wanted to tell him/her. Maybe you were distracted by a previous conversation with someone else. This is a simple form of a Buffer Overflow. You wanted to relay a message, which would have formed the basis for future decisions. But a disruption in your planned series of events prevented it from occuring. See the connection???
 
Significance of Buffer Overflow Vulnerability....

Reference the above example of the Mexican air controller.... In the field of IT, such behaviour can result in serious trouble, as in the case of the Mexican air controller.

A buffer overflow occurs when a program or process tries to store more data in a buffer (a temporary storage area in RAM) than it was intended to hold. Buffers are created to hold a finite amount of data, so the extra information has to be moved elsewhere, and can overflow into adjacent buffers, corrupting or overwriting the valid data held in them. 

Consider the following snippet of C++ code:

#include <stdio.h>
int main ( )
[
char name[31];
printf ( Please type your name:   ");
gets(name);
printf("Hello,   %s",    name);
return D;
]

A Buffer Overflow will occur if you enter:
'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'