Today i was reading an interesting article on VM Escaping. Maybe it could be old to some people, maybe it could be new to some people.
http://habrahabr.ru/company/dsec/blog/222993/

Inside the article, the author also release an interesting POC of VirtualKD vm DoS exploit.
https://www.dropbox.com/s/apggjgla0j3c6rt/vkd.zip

You can watch the demo here.
http://www.youtube.com/watch?v=R9OrT1g8N6U

BR,
[ Gunther ]