On the surface most common browsers (user agents) all look the same, function the same, and deliver web content to the user in a relatively uniformed fashion. Under the surface however, the way specific user agents handle traffic varies in a number of interesting ways. This variation allows for intelligent and skilled defenders to play with attackers and scripted attacks in a way that most normal users will never even see.
This talk will attempt to show that differences in how user agents handle web server responses can be used to improve the defensive posture of a website. Further examples will be given that show specially crafted responses can disrupt common automated attack methods and cause issues for casual attackers and wide scale scanning of websites.