The Dangers of Public Proxies

Wednesday, February 20th, 2008

Introduction.
Public proxies are often used by employees or students who want to get around Web filters and/or avoid being identified by Internet logging. In other words, public proxies allow individuals to surf the Web “anonymously.”

The way public proxies work is by making the requested Web site appear to be going to a Web address other than the address of the site actually being requested. They act like a “middle man.” When a Web site is requested, the request is sent to the public proxy, which forwards the request to the original destination, and then returns the site that was requested.

Problems with Public Proxies.
The claim that a public proxy hides a user’s identity may sound safe, but the fact is that public proxies that are used to get around filters can be very dangerous to the user and his/her company or school.

Many public proxies promote spyware or malware activity. They are created to gather user information, or even worse, company information on an employee’s computer. They often log an individual’s online browsing, emails, and chat sessions to gather user names, passwords, credit card or banking information. Some of the information gained, e.g., email addresses, is often used to sell to other companies for marketing purposes.

Solutions.
An enormous and fast-growing number of dangerous public proxy sites exist around the world with new ones popping up every day. Many of them even change their IP addresses at frequent intervals. For these reasons, it is totally impossible to completely solve the problem with technical approaches alone.

Instead, there are several steps you can take to prevent or identify the use of public proxies. The first is to make sure your company or school’s acceptable use policy and consequences of breaking that policy are clearly communicated.

Secondly, back up your AUP by filtering and/or monitoring employees and students’ Web access. Many public proxies use IP addresses to avoid easy detection, so a spike in IP address visits could be an indication that an employee or student may be using one. Wavecrest Computing’s CyBlock and Cyfin Internet filtering and monitoring software have categories for both public proxies and IP addresses.

Finally, make sure that your employees or students are aware of the security dangers associated with public proxies. Many are not aware of the security risk associated with public proxies and may be less inclined to use one if they are educated on the dangers they pose to the user and his/her company or school.