Schools long have struggled with savvy students who run anonymous Web proxy tools to bypass Web filters and secretly access banned Websites and content. But the use of these potentially dangerous tools within the enterprise appears to be more widespread than was once thought.

A new study released today indicates that businesses may be clueless about the breadth of the problem: While 15 percent of IT managers report that Web filter bypass tools are in use in their organizations, it turns out that these tools are actually in use in three out of four organizations, according to FaceTime Communications, which polled both IT managers and its own customers on the topic.

"In some cases, the perception is not reality," says Frank Cabri, vice president of marketing and product management for FaceTime, whose customers provided the actual usage data in the study. "This doesn't surprise us -- but the difference [in perception and reality] is dramatic."

Anonymous Web proxies, also known as proxy servers, anonymizers, and shadow-surfing tools, basically pass user Web traffic via other servers to get around an organization's Web filters. These tools come in various forms, but the most popular are Web proxy sites, such as Proxyatwork.com, which let users reach banned sites from work, whether it's gambling, social networks, or adult content. They also come in desktop applications, such as Circumventor, that let users browse silently and anonymously over nontraditional browsing ports, hiding their IP addresses and other identifiable information.

Other bypass tools include online communities, such as TOR and Hopster, where users make their PCs available for use as proxies in support of freedom of communication over the Net, Cabri notes.

"It's impossible for an organization to block access to all those sites, which are growing by large numbers each day," he says.

Unauthorized Web proxy usage is nothing new to academia. In a recent survey of schoolchildren by SmoothWall, 55 percent of students said they had seen another student go on an adult Website at school, while 49 percent of 13- to 17-year-olds said they had accessed blocked Websites from school.

But security experts say enterprise users are increasingly masking their Web traffic comings and goings with anonymizer and proxy technology more than many companies realize. This is, in part, due to a generation of young workers graduating into the "real" world of the office who are accustomed to freely accessing social networks and other real-time communications media that may be banned in a business setting, or who have experience using proxies.

Sophos says about 58 percent of the organizations it helps block access to these Web proxies are colleges or school systems, and 42 percent are from the business world -- mostly in media/broadcasting, public services, hospitals, and law firms. "Although most of the institutions we have encountered who are suffering from abuse of Web anonymizing proxies are educational establishments, a higher number than we expected are corporations," says Graham Cluley, senior technology consultant for Sophos. "So although schools and colleges may have more users trying to avoid their Web filtering solutions, it definitely is a problem in business, too."

And the number of Web anonymizer/proxy tools has grown rapidly, tripling over the past two years, says FaceTime's Cabri. The trouble for businesses, of course, is the potential for silent malware infections, data leakage, and legal problems. "They don't know what's going on with the apps users are accessing with those proxies," he says.

And bypassing a Web filter typically means the traffic is bypassing anti-malware gateways, as well, notes Tom Newton, product manager for SmoothWall. Not knowing the risks your users are taking or where they are picking up potential infections leaves the organization wide open to attack, too. "The whole point of the tool is that it's untraceable," he says. For an organization to detect this unauthorized Web behavior is "a lot about having some oversight on what's going on in the network," he says.

Stewart Allen, a Toronto-based independent consultant, says enterprise use of proxies isn't necessarily increasing -- it's just an ongoing problem. For the most part, bypassing filters isn't overly difficult: Less-technical users can Google to find anonymizers or proxy services, while more sophisticated users can set up a "jump station" in their homes that they can use from work to go out to the Web unrestricted, he says.

But users who go to these lengths to bypass security don't want to get caught, so they are typically not easy to find. "The people who know how to get around Web proxies also know how to get around almost any other type of security," says Robert "RSnake" Hansen, founder of SecTheory.

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