Skype could pose security problems for companies, analysts say

Computerworld - The growing popularity of Skype Technologies SA's free Internet telephony software could soon pose the same kind of security challenges for companies that other peer-to-peer (P2P) software technologies have created in recent years, according to security experts.
The warning comes after the disclosure this week of two critical flaws in Skype's software, one of which could allow malicious hackers to take complete control of compromised systems.
One of the flaws is a buffer overflow error in Skype's user client for Windows that could allow attackers to execute arbitrary code on compromised systems, according to a statement from the company. The other vulnerability is a heap overflow flaw in a networking routine affecting Skype clients for all platforms. That flaw could crash the client software.
Fixes for both problems have been released.
Skype, which was recently acquired by eBay Inc. for $2.6 billion, offers downloadable software that allows PC users to make free Internet telephone calls to each other and low-cost calls to telephone users.
So far, Skype has garnered more than 61 million registered users, approximately 30% of whom use it for business purposes, according to the company. Almost all of that adoption has been in Europe and Asia, though analysts expect Skype to eventually gain wide accepted in the U.S. as well.
According to Stamford, Conn.-based analyst firm Gartner Inc., eBay's purchase of Skype could result in a product more suited for corporate use.
In the meantime, business users should refrain from using "voice services based on proprietary protocols like Skype while on corporate networks because of network security issues," Gartner said in a Sept. 15 advisory.
There are several reasons for the concern, industry experts said.
"Skype is VoIP on steroids," capable of punching holes through many of the network defenses that companies typically deploy, said Tom Newton, product manager at SmoothWall Ltd., a Leeds, England-based vendor of firewalls and other security products.
Like other P2P technologies Skype allows users to establish direct connections with each other. It's also "port agile," meaning that if a firewall port is blocked Skype will look around for other open ports that it can use to establish a connection, Newton said. "If you put Skype behind a firewall or Network Address Translation layer, 99 times out of 100 it will work" without any special configuration, he said.
As a result, Skype could provide a backdoor entry into otherwise secure networks for Trojans, worms and viruses, Newton said. It could also provide a channel for corporate data to be freely shared between users