Virtualization: Security Tipping Point?
Does virtualization's new high profile warrant security worries?
Are VM Environments Open to Attack? - LinuxInsider
And that's just one example...
The mobility of virtual environments can also create a security quagmire. Virtual machines can "walk off": Since their containers can be downloaded to desktops and put on a memory stick, on which they can then leave the physical security perimeter.
"Virtualization can be implemented and systems can be as secure as if they were running in an environment natively, Eric Mandel, CEO of managed hosting services firm BlackMesh, told LinuxInsider. "The idea behind using virtualization is to carve out multiple system [images] on one physical machine. The same security concepts apply to the virtual images as they do to a native system, with the exception that the owning system has to be locked down as well. There are always security risks that have to be considered in any environment."