Buffer Overflow Primer Part 9 (Return to Libc Demo)

Welcome to Part 9 of the Buffer Overflow Primer. If you have not already done so, please start this series by viewing Part 1. The Buffer Overflow Primer requires that you know at least some basic Assembly Language. I have created a series of Assembly Language video tutorials for Hackers here, for those not familiar with the language.

In this video we will do a hands on demo of exploiting a stack protected by NX using the Return to Libc exploitation process. We use GDB and attach it to the vulnerable program to find the address of "/bin/bash" in it's memory. Once this address is found, we modify Ret2libc.c and launch the attack on the vulnerable program. The successful exploitation leads to spawning of a shell. As we are using a 2.6 kernel in the video, we temporarily disable the ASLR feature. We will look at how to exploit a buffer overflow in presence of ASLR in a later video. Please download ExploitMe.c, Ret2Libc.c and GetEnvironmentVarAddr.c to follow the video.

Vivek Ramachandran is a security evangelist and has been working in computer security related fields for the past 7 years. In 2007, Vivek spoke at world renowned conferences Defcon (WEP Cloaking Exposed) and Toorcon (The Caffe Latte Attack). The discovery of the Caffe Latte Attack was covered by CBS5 news, BBC online, Network World etc news agencies.In 2006, Vivek was announced as one of winners of the Microsoft Security Shootout contest held in India among 65,000 participants. He has also been a recipient of a Team Achievement at Cisco Systems for his work on 802.1x and Port Security modules on the Catalyst 6500 switches. Currently he spends all of his time maintaining Security- Freak.Net , SecurityTube.Net and is the co-founder of Axonize. Vivek, is a Bachelor in Electronics and Communications Engineering from the prestigious Indian Institute of Technology, Guwahati.You can contact him at vivek[at]securitytube.net