WiFi and other wireless network technologies have increased the risk of eavesdropping on Internet communications. To combat this threat, researchers at Carnegie Mellon University have devised a low-cost system that promises to thwart so-called "Man-in-the-Middle" (MitM) attacks.

The Carnegie Mellon system, called Perspectives, also can protect against attacks related to a recently disclosed software flaw in the Domain Name System (DNS), the Internet phone book used to route messages between computers.

MitM is a type of active eavesdropping where the attacker makes independent connections with victims and relays messages between them. The technique tricks victims into believing that they are conversing directly to each other over a private channel when, in fact, the entire conversation is being controlled by the attacker.

Perspectives utilizes a set of friendly sites, or "notaries," that can aid in authenticating Web sites for financial services, online retailers and other organizations with transactions requiring secure communications. By independently querying the desired target site, the notaries can check whether each is receiving the same authentication information, called a digital certificate. If one or more notaries report authentication information that differs from the type received by the browser or other notaries, a user would have reason to suspect that an attacker has compromised the connection.

Certificate authorities, such as VeriSign, Comodo and GoDaddy, already help authenticate Web sites and reduce the risk of MitM attacks. The Perspectives system promises to provide an extra measure of security while also helping the growing number of sites that don't use certificate authorities and instead rely on less expensive "self-signed" certificates.

The Carnegie Mellon researchers include David Andersen, an assistant professor of computer science; Adrian Perrig, an associate professor of electrical and computer engineering and public policy; and Dan Wendlandt, a Ph.D. student in computer science. The team has incorporated Perspectives into an extension for the Firefox 3 browser. The extension can be downloaded at no charge at www.cs.cmu.edu/~perspectives/firefox.html.

"Perspectives provides an additional level of safety to browse the Internet," Perrig notes. "To the security conscious user, that is a significant comfort." Andersen notes that the increased use of wireless connections to the Internet has raised the risk of MitM attacks. "It's very, very, very easy for someone to convince you to go through their computer" when making connections through public WiFi, he says. A user who thinks he is linked to an airport or coffee shop "hotspot," for example, might actually be linked to a laptop located just a few seats away. "A lot of people wouldn't even know they've been attacked," he adds.

Copyright 2008 PricewaterhouseCoopers. PricewaterhouseCoopers refers to the network of member firms of PricewaterhouseCoopers International Limited, each of which is a separate and independent legal entity. All rights reserved. The preceding article was written by John Edwards, a freelance technology writer based in Gilbert, Arizona. He can be reached by phone at +1-480-854-0011.