Anyone know of good format string vulnerability tutorials/videos that demo how to test on a web app, such as modifying the URL. I've watched Vivek's videos from securitytube and another from CarolinaCon, but am looking for a more detailed/visual demo of how to apply it in web app pen-testing. In addition, I have seen other vulnerable web apps such as Damn Vulnerable Web App and Webgoat, as well as a few others, but can't seem to find how an attacker can exploit a format string vulnerability via a web browser and how to protect against it, other than modifying the code of the vulnerable link and/or program.

This all stems from reading different external scanning reports that always seem to contain Format String Vulnerability located at www.domainname.com/default.asp?(insert name here and code, ex.) News=%2508x. What exactly should I be looking for and how is someone supposed to investigate/test this (tools, manual, etc.)?

2 Answers 2


The OWASP Testing Guide has some guidance, as well as some whitepapers and references to tools.

WASC has this entry.

There scanning tools that look for this kind of vulnerability. w3af has a formatString plug-in that might help you test, depending on your application's setup.

Other than these things, I assume you learned from the videos to test for printf formatting characters. If you add these characters to a dictionary and fuzzing attack on inputs, you can determine the vulnerability of the application, if not exploit the vulnerability.


Check The Defcon Conference Videos, I am sure There are some videos about what you want.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .