Or a viable defense. What's even more alarming, perversion of your web applications isn't even a particularly sophisticated form of hacking. And as sites become ever bigger and more sophisticated, the number of holes will only increase.
Web applications consist of bugs, backdoors, poor input sanitization, and weak state control.
But unlike traditional vulnerabilities at the network and operating system level, the problem is compounded by the fact that no robust products currently exist to locate these web specific problems.