Saturday, January 21, 2012

Are Virtual Servers Secure?

Data center consolidation is now a key goal of DoD CIOs. With close to hundred thousand servers virtualization has become technically the most expedient way for achieving the downsizing of computing services. Whether the hosting of several servers into one computer will result in the reduction of data center sites remains to be shown. It will require a re-design of networking before the shrinkage into dozens of computers will make it possible to support millions of desktops from only a limited number of locations.

Shrinking thousands of workloads into hundreds of virtual computers greatly increases the complexity of the computing environment. It creates new security risks, which the consolidated environment must address. There is no question that any migration of applications to a much smaller number of platforms will magnify the exposure to compromises. DoD cannot tolerate increasing security risks even if large cost savings are available. Up to 70% potential reductions in the number of servers cannot be used as an offset against the rising costs of security and protection.

The traditional approaches to security offered security by increasing the size of the attack points available to an adversary. The multiplicity of data centers, each managed individually, provided a measure of protection so that targets would be hard to find. However, virtualization now reduces diversity through consolidation of processes and practices. Targets are now much larger and offer an opportunity for collecting compromising results from a collection of applications.

What used to be sufficient in dealing with a fractured legacy environment of only a few dedicated servers cannot cope with an environment where a single pool supports dozens or even hundred of applications. For instance, in a virtualized server pool applications will dynamically relocate not only during normal operations, but also whenever fail-over conditions dictate a shift of processing to a completely different set of servers. A security breach, which was previously contained to an isolated location, will now propagate across a multiplicity of sites while opening and shutting down as capacity optimization dictates. If a virtual host computer is compromised, the consequences can be potentially catastrophic.

Virtualization creates a hypervisor layer, which clouds the visibility of intra-virtual machine communications. In a well-developed virtualized environment a single hypervisor could manage as many as dozens of virtual servers, continually re-arranging the assignment of devices so that a security breach would not be detected. For instance, firewalls, used to be assigned individually, would now act only as a barrier for a cluster of applications and not individually for each separate virtual machine.

Data center consolidation is now proceeding. It concentrates on server virtualization as the preferred method for achieving quick capacity utilization benefits. Unfortunately, it will take more than the application of hypervisors to a cluster of virtual computers to offer a reduction in the number of data centers. Server virtualization represents a persistent vulnerability. To cut down the number of data centers will require changes how DoD computing is organized and particularly how security is managed.


  1. I am a Dell employee and I enjoyed reading your blog about "Are Virtual Servers Secure?". It talks about the main conern of server security and provides a very detailed analysis. Thanks for sharing this with us.

  2. This blog is really very nice blog but I have question is that how much cost effective virtual servers for small business users?


For comments please e-mail