For IT security pros, the rise of virtualization is a double-edged sword. On the one hand, it offers the prospect of squeezing more computing cycles from server hardware in tough economic times. On the other hand, it presents the unpleasant prospect of one compromised virtual machine affecting many others.

One strategy that may offer a happy medium is desktop virtualization, which gives enterprises some of the hardware-sharing advantages of virtualization, but with a much lower security risk. In fact, some desktop virtualization vendors specifically promote their technologies as security solutions.

Desktop virtualization vendors such as Trustware, Kidaro, and Sentillion claim to prevent malware infections and data leakage by taking one of two different approaches. Some allow untrusted applications like Web browsers and instant messengers to run in a "virtual" layer to protect managed machines from unintended damage. Others provide a secure virtual desktop environment so that secure, legitimate business can be performed on unmanaged, untrusted machines, such as an employee's personal laptop.

The two approaches are different, but their underlying premise is the same: Desktop virtualization can be used to prevent malware and data leakage. This is a message that runs completely contrary to server virtualization, where security vulnerabilities are considered to be a major obstacle.

How can desktop virtualization be viewed as a security solution? Instead of virtualizing an entire hardware environment to run a full operating system, GreenBorder, which was purchased by Google last year, and Trustware BufferZone virtualize untrusted applications’ access to the hard drive, registry, and even network access so that changes to the system are written to a temporary location, preventing permanent damage to the host.

"BufferZone allows you to download, open, and install anything, without damage to your computer," says Eyal Dotan, CTO of Trustware and developer of the BufferZone. It’s a bold claim, but Trustware is putting its money where its mouth is: The company's home page sports an offer of $500 to anyone who can break the latest version of its software. Enterprises aren't likely to make such an offer to their own users, but it might give system administrators peace of mind to know that zero-day exploits -- such as the Adobe Flash attack demonstrated recently at the CanSecWest PWN to OWN contest -- won’t impact sensitive data in files that are out of the purview of the browser.

Kidaro, which was acquired by Microsoft last month, and Sentillion take the second approach to desktop virtualization, leveraging existing technologies such as VMware, Microsoft Virtual PC, and Parallels Player.

This is a complete, 180-degree turn from the Trustware approach. In the Kidaro and Sentillion environments, corporate applications that are considered "trusted" are forced to run in a secure virtual environment. These applications are forced to operate under special security restrictions -- they may not be allowed to copy data to or from removable media, they may be limited in their copy-paste capabilities, or they may be forced to send traffic over a VPN.

Which approach is right for your enterprise? If you’re looking for an extra layer of protection against the dangers associated with Web browsing and instant messaging, then Trustware’s BufferZone might be a good fit (GreenBorder’s solution is no longer available since its purchase by Google). BufferZone Enterprise offers centralized management using Group Policies in Microsoft Active Directory; a firewall to control network access to/from untrusted applications; and granular control over what files, folders, and storage devices are accessible.

For enterprises that must deal with unmanaged computers -- such as personal and contractor laptops -- the trusted virtual desktop is a better approach because all business-related activity can be confined to the virtualized environment. Control over file and folder access, network connectivity, removable media, printing, and other functions are all centrally managed. The VM and any files copied from it are encrypted, eliminating concerns about storing VM files on unmanaged computers.

Are these virtualization solutions truly secure? Without more real-world research on these very new technologies, it's hard to say just yet. That may change, now that Google has purchased GreenBorder and Microsoft plans to integrate Kidaro into the Microsoft Desktop Optimization Pack.

Having spent some time with Trustware’s BufferZone in our testing lab, I can say it’s definitely an interesting product, and does what it says. But can these products find traction in enterprise environments? Unfortunately, at this stage, it’s hard to tell. But it's definitely worth keeping an eye on these technologies as they mature.

Have a comment on this story? Please click "Discuss" below. If you'd like to contact Dark Reading's editors directly, send us a message.