That's where IBM and AMD come in. AMD's scientists had similar concerns to the NSA's, so they designed an authentication mechanism at the chip level that would be able to control what hardware could do with the virtualization engines that rely on their AMD-V on-chip virtualization assistance technology. While no ship date has been announced, a new generation of AMD-V chips expected later this year will introduce the concept of chip-managed trusted hardware, said Steve McDowell, division manager for emerging technologies at AMD. Intel is expected to ship a similar technology as well, said Kurt Roemer, chief security strategist at Citrix Systems, which recently bought hypervisor maker Xen.

These new chips will have what AMD's McDowell calls a "device exclusion vector" that can authorize or block hardware access to VMs, as well as create a chain of permissions that flow from one device to another, so OS and hypervisor developers can control not only what hardware can do what, but also what flows among hardware devices are permitted. McDowell expects this approach to prevent the subsystem-as-spy problem that both it and the NSA identified.

Using virtual layers to add security
While virtualization is used commercially to have multiple operating systems run on one machine -- to get more usage from physical servers, to run Windows on Macs, and to easily set up testbed environments -- its origins trace back to a military security need. In fact, the VMware technology that popularized virtualization is a spin-off of Defense Department-sponsored research done at Stanford University; the military saw early promise in virtual machines to encapsulate networks and desktops from outside threats, resulting in an NSA-created OS called NetTop that in 2001 did for Linux what products such as Parallels Desktop and VMware Desktop do today: provide separate VMs that can't affect each other on one box.

Now the NSA sees virtualization protecting systems in a new layering approach, Simard said. The idea is to have an independent layer handle security, so even if an OS has security flaws, a separate layer that the OS can't compromise handles security threats such as viruses and worms or implements firewalls. Simard said it's inevitable that PC operating systems will have security holes: "The PC platform is a very feature-rich platform, and being feature-rich gets it into trouble."

The NSA, working with General Dynamics and IBM, has developed the first version of this technology, which it calls the High Assurance Platform workstation, for the U.S. Special Operations Command, using VMware, Novell SuSE Linux, and Red Hat Linux, Simard said.