Chapter 12. Web Intrusion Detection

In spite of all your efforts to secure a web server, there is one part you do not and usually cannot control in its entirety: web applications. Web application design, programming, and maintenance require a different skill set. Even if you have the skills, in a typical organization these tasks are usually assigned to someone other than a system administrator. But the problem of ensuring adequate security remains. This final chapter suggests ways to secure applications by treating them as black boxes and examining the way they interact with the environment. The techniques that do this are known under the name intrusion detection.

This chapter covers the following:

• Evolution of intrusion detection

• Basic intrusion detection principles

• Web application firewalls

• mod_security