About Stack Buffer Overflow Exploits

Question

I'm trying to learn how to write exploits for stack overflows by installing random apps from SourceForge and testing them with bad inputs.

I faced some programs where the app crashes but my input doesn't overwrite the EIP register... What should I do about that? I also noticed some apps were developed in Visual Basic and they just show a message box saying the input was too long and the app crashes.
My desktop is full of new apps that I just downloaded for testing. Is there a way to test apps without filling my computer with them all the time and also without taking the risk of running some bad apps?

For number 2 you could install and run a VM(Virtual Machine) — sharf, Jul 09 '14 at 22:30
It looks like you want to do Project 1 for Stanford's [CS 155](https://crypto.stanford.edu/cs155/) course. — merlin2011, Jul 09 '14 at 22:38
I did try some vulnerable program examples that I followed on online lessons about exploiting stack overflow. I'm facing this in real life .. The app crashes and EIP is not overwritten !! — user3396251, Jul 09 '14 at 22:50
Not sure what kind of answer you expect for #2 there... I mean, install fewer apps at a time? Don't test desktop apps? Set up a VM? There isn't really any particular trick to it. — Adam Lear, Jul 09 '14 at 23:38

score 0 · Answer 1 · answered Jul 10 '14 at 08:38

The best alternative is to use a Virtual Machine, so you can run apps without affect your computer, sometimes there are a lot of virus on them.

You can use software like VMWare or "VirtualBox" for make your own Virtual Machine, and start testing on Kali or where you want to test

score 0 · Accepted Answer · answered Jul 11 '14 at 14:21

To answer your questions in order:

The overflows you're seeing may require SEH exploits, where the crash triggers the structured exception handler (SEH), rather than simply overwriting EIP. It may of course, be that the program simply cannot be exploited. Take a look at this tutorial on corelan for details of SEH exploits.
As suggested by blackbird, using virtual machines would mean no cluttering of your own machine. Of course you would need a Windows ISO or image to install for working on Windows based apps, or you could install a Linux distro and concentrate on Linux apps.

Note that a better approach to learning may be to practice on apps from exploit-db - that way you know they are vulnerable and the POC will show you where they are exploitable. Start with something easy like the Ability FTP server or again check the tutorials on corelan.

About Stack Buffer Overflow Exploits

2 Answers2