A special group from security analysts and white hat hackers had been created to crack the hypervisors. Although one method seemed to be harmful, it soon appeared that it is detectable and addressable. It seems that the only way to hack virtualization software is to do it straight from the insight of server room and using special software.
There has been a controversial statement in April that warned organizations that there are some security risks, and that they shouldn’t rush into deploying server virtualization. Although they have released some security and management tools, those were said to be immature and incomplete. As far as virtual servers are easy, cheap and quick to deploy, most of users doesn’t pay any attention to possible security risks.
Read this musing.