150 ways to bypass ordinary WAF's but not ours, by design!

At BH US 2012, Ivan Ristic showed off a new tool called IronBee which contains 100+ possible ways to bypass WAFs. As he focused on getting past the open-source ModSecurity WAF, other ordinary open source and commercial WAF's fall obviously prey to these attacks too. By design WAFs try to protect on the wire, lacking all the context they need to achieve proper protection. Check out where the HP Fortify RTA solution is looking for malicious behavior and where ordinary WAFs are trying to protect.



In essence, for every piece of data in the request, a WAF has to decide if it let the data go through or not WITHOUT a clue where the data will be used. Common attack patterns are easy to spot, but when the data is encoded, encrypted, obfuscated and so on, a WAF will quickly miss something and that is exactly what Ivan is pointing out. It is so hard to know how to treat the data when it's not known how the data will be used in the application itself. By design, HP Fortify RTA does not have to go through the hassle of decrypting, decoding, normalizing and so on. RTA waits until the data is used in the application itself and will then interfere if the data is used in an inappropriate way. There is so much more context inside the application!