For all its benefits, the drive to virtualize everything has created a very big security issue: Virtualization creates a single target for a potential security breach. When a host runs 50 virtual machines (VMs) and is attacked, then you have a real problem. One compromised host compromises the 50 VMs running on it, and now you have what I lovingly call a “holy s**t” moment. Because you virtualized, you turned a whole bunch of servers and operating systems into just a couple of files that are super easy to steal.
Read more here:: IT news – Virtualization