Caution: Articles written for technical not grammatical accuracy, If poor grammar offends you proceed with caution ;-)
Security is huge when it comes to virtualization. The extra moving parts require a special care and feeding. The Defense Information Services Agency is basically the IT department for the US Defence Department. They have an arm, called the Information Assurance Support Environment. The IASE is a has some serious information about securing any system. They post Security Technical Implementation Guides (STIGS) and Security Checklists that are very comprehensive. They even have STIGs and Checklists for all the different versions of winders. Some of the information is specific to the DoD, but those things, like certificates, etc. still have a place in any IT shop. I subscribe to their newsletter, so they just came to mind again because they posted a Draft XenApp STIG. I glanced at the docs, but they look pretty deep and I have reading narcolepsy…
So, why do I bring this up? They also posted a STIG for ESX Server a while ago and recently posted an updated Security Checklist for ESX. I know that Sid used these as a guide for his kickstart / post installation script. When coupled with the Unix STIG and Checklist, you will get a very secure system. So go check them out. They a free and that is my favorite price. So go get some.