Will infrastructure virtualization sweep away existing switching structures while failing to grant benefits of performance, cost or improved security? Some say yes.

Virtualization "will not save you money, it will cost you more," said Christopher Hoff, chief security architect at Unisys. In addition, "virtualized security can seriously impact performance, resilience and scalability," he said in an impassioned presentation Wednesday at the Black Hat conference.

Hoff argued the user community is being sweet-talked into virtualization by an industry unmindful of the security consequences.

The next 12 to 18 months will bring an uncomfortable set of circumstances as every vendor rushes to claim it is virtualized, Hoff said in his talk titled "The Four Horsemen of the Virtualization Apocalypse."

"It's getting real messy," Hoff said, as Cisco, Brocade Communications, 3Leaf Systems and Xsigo Systems, among others, gallop off to virtualize basic switching infrastructures without a clear notion of what the security consequences are for enterprise customers accustomed to wholly different topologies that include such technologies as Spanning-Tree Protocol.

"A virtual switch is just a piece of code like a hypervisor," Hoff said about the industry's new direction. "It's basically Layer 2 switching modules," he said, which means you've collapsed the network into "a single tier" and "it all boils down to three settings in a GUI."

Virtual security is taking shape in the form of virtual appliances that will become the cornerstone for trying to replicate such traditional defenses as intrusion-prevention systems, antivirus and firewalls, Hoff said. As security functions compete for virtual-machine resources, however, there will be a performance hit, just as is seen in unified-threat-management devices today that combine IPS, firewall and other functions, he said.

Capacity planning with a virtualized network is going to be very difficult to predict, Hoff said, adding he was profoundly skeptical that trying to virtualize a firewall is going to work as DMZs are pushed into going virtual, too.

"If I decide to V-Motion a firewall, it won't work," Hoff said, alluding to his own research with VMware and its V-Motion capability for deploying virtual-machine images rapidly. He also warned of the threat of virtual-machine sprawl, where I can't even track down in my network where this thing is.

With virtualization, "you won't get rid of host-based security software. As we add more solutions, we add complexity," Hoff said, advising the Black Hat audience "not to be dragged into the environment."