There are technical controls [tools such as Vontu] available to monitor deviant computer usage of employees of a company. It is extremely difficult to catch a smart-deviant employee. An intelligent alternative is to catch not-so-smart-deviant employee to trigger a warning message to smart-deviant employee - [smart-deviant employee could either become smarter or they could just shut up!]. Typical examples of not-so-smart-deviant employee behaviour are: 1. Sending confidential document to a competitior through an email attachment. 2. FTP'ing confidential document outside of the company. 3. Using webmail to send confidential document.

Mike Rothman's blog post about spammer's using encrypted zip files to tunnel thro' filters demonstrates the brilliance of smart hackers. It is well known truth that HTTP is known as UFBP (Universal Firewall Bypass Protocol). What if a hacker tunnels encrypted data thro' a SOAP container which uses HTTP? It would be extremely hard to catch those extreme cases with technical controls.

Jeremiah's thoughtful  blog post about  "How to check if your WebMail account has been hacked". A smart hacker who has hacked say your gmail account would not be dumb enough to open a spurious looking email in the first place, moreover they would get around by choosing the option of not displaying images!

Smart hackers get away most of the time. There is no point in spending cycles to catch them. Hope for the good by catching not-so-smart hackers! Do make sure when you catch not-so-smart, it leads to widespread educational opportunity.