Home » Data Protection » Application Security

In Depth

Anonymous Proxy Servers: Necessary Or Evil?

Some security experts believe anonymous proxy servers are only necessary if you're up to no good, while others see them as a legitimate tool for research, pen testing and the like. Who's right?

By Bill Brenner, Senior Editor

October 14, 2008 — CSO —

First in a series.

If there is truly a gray zone in the struggle between online good and evil, anonymous proxy servers live there.

Organizations typically use proxy servers to forward website, file and other requests to other servers. Anonymous proxy servers are meant to hide the identity of the requestor.

Some security experts say the latter is only necessary if someone wants to mask malicious activity, including Sunil James, senior product manager at Amazon Web Services and formerly director of vulnerability research at iDEFENSE Inc.

"As a security person my natural first instinct is to ask why someone needs to be anonymous if they are doing something legitimate," he said. "I just don't see a viable use for anonymous proxy servers in corporate environments."

Others say certain kinds of security research and testing make them a necessity and that they are perfectly safe if used responsibly.

In an effort to reach a consensus on the issue, CSOonline polled several industry professionals by phone, e-mail and networking sites like LinkedIn.

Surprisingly, most respondents defended the use of anonymous proxy servers and offered a litany of legitimate-use examples. But everyone admits they can easily be used for malicious purposes and that organizations need to respond with the right security procedures.

"From a security perspective, hiding your true location behind a proxy definitely falls in the gray area of Web browsing," says Ed Ziots, a Rhode Island-based network engineer. "I use them to view questionable content from semi-trusted systems because I do not want the site to know the true origin of my communications when I am researching the latest exploits, exploit code, or new and up-and-coming trends in exploit research."

But he can imagine a more sinister scenario where the bad guy uses multiple anonymous proxies so victims can't determine where his attack sequences are coming from.

Spying (or blocking) competitors
Anonymous proxy servers are often used to spy on competitors or block their efforts to do the same to another competitor, says Chris Kraft, VP of product management for web security for security vendor Sophos.

"This tends to be used for competitive purposes in which a website operator can identify the IP range of competitors and prevent them from viewing the company's assets," Kraft says. "It can be used to gather intelligence on your competitors, and the competitors in turn can use anonymous proxies to block your activities."

During his time as the CISO of a Fortune 100 company, security consultant Larry Glassman received a request from the sales and marketing department to establish an anonymous proxy server so the marketing department could perform competitive market analysis against a competitor in the space.