"In 2007, you will see a huge up-tick in [the number of] people discovering vulnerabilities and putting out tools to defend against them," said David Endler, director of security research at 3Com's TippingPoint security division, Austin, Texas. Endler recently co-authored a book with Mark Collier, CTO of SecureLogix, San Antonio, called "Hacking Exposed VoIP: Voice Over IP Security Secrets and Solutions."
The rising profile of VoIP security issues is a trend that's been building throughout 2006, Collier said.
"VoIP is still a relatively new and uncommon technology, but we're starting to see more tools, more books, more focus at hacker conferences," Collier said. "A year ago at Black Hat, there was very little discussion on VoIP. This year, there was a whole track," he said, noting that the SANS Institute this year for the first time listed VoIP among the top 20 Internet security attack targets.
The authors highlight the potential risks of enterprise VoIP deployments, such as denial of service, network eavesdropping and call manipulation. They also built several VoIP security diagnostic tools that can be used to test networks against threats.
The question of hype vs. reality is one that has plagued VoIP security discussions for several years. While many industry observers concede that theoretical risks exist, they argue that they have yet to be exploited in the real world. Some even argue that VoIP deployments are more secure than traditional telephony.
"It's interesting to me to talk a greater risk than traditional telephony: with that, you just had to splice in and you could listen," said Richard McLeod, director of unified communications for worldwide channels at Cisco Systems, San Jose, Calif. "IP mitigates that. You can't really splice in and listen to bits and bytes."
Solution providers said most of the risks they see related to VoIP are tied to the inherent risks to network security and are not specific to IP telephony. Nevertheless, many VoIP security problems can be avoided through careful configuration, solution providers said.
"We view it as our responsibility to educate customers on the risks," said Sadik Al-Abdulla, security engineer at Berbee Information Networks, a Madison, Wisc.-based Cisco partner owned by CDW, noting that he expects more hackers to turn their attention to VoIP as it becomes more widely deployed.
In general, the fewer devices allowed to talk to the IP phones on a network, the better, Al-Abdulla said. "In many cases, people let the network talk to the phones, and they really shouldn't. By and large, only the call manager or certain XML application servers should," he said.
He also recommends limiting administrative access to the call processor in a VoIP deployment. "That's a real risk, and one of the most serious risks on any network," Al-Abdulla said. "If you maintain good administrative control, you're in better shape."