A whitepaper on Proxy Abuse

From SmoothWall's 2009 whitepaper

Anonymous proxy servers that pass users' web requests onto other servers on the internet are becoming an increasingly pervasive problem in schools – and one that can only be prevented with intelligent filtering solutions. Anonymous proxies pose a problem for educational establishments that need to safely control and monitor their users' web access. For instance, students can use anonymous proxies to browse secretly and view banned online content without disclosing the URLs they visit to filtering devices. Although keyword-based filters will catch sites with 'proxy' in the title, most have legitimate-sounding names like examstudies.com . Using a web filtering solution that doesn't block proxies is the equivalent of putting a big bolt on your front door but leaving the back door wide open.

How do Students find out about Anonymous Proxies?
Try entering "unblock myspace" into Google – the results run to hundreds of thousands of sites, all offering the same thing – anonymous browsing. These 'Backdoor' URLs are passed quickly from student to student, and there are also plenty of step by step videos on YouTube showing students how they can use proxy tools to bypass school filters. These are the very skills that we don't want our children to learn in school – digital lockpicking and worldwide web breaking and entering.

Risks of Proxy Abuse
Legal risks: Although schools are not yet facing lawsuits for security breaches due to anonymous proxies, a protective parent may eventually decide to prosecute. American schools must comply with the Children's Internet Protection Act (CIPA), a federal law enacted by Congress in 2000 designed to protect children using school, college and library computers from offensive Internet content. All obscene, harmful and pornographic content must be blocked and all student web use monitored. Institutions that fail to comply risk losing e-rate funding.

Malware: Proxy sites also help malware and other web-related threats to sneak into networks undetected. SSL proxies are a particular problem since the secure tunnels used allow malicious viruses and worms to sidestep firewall and web filtering security entirely.

Phishing and password theft: Many students who use proxies are unaware of the risks to their own personal security and identity. Malicious proxy servers are capable of recording everything sent to the proxy, including unencrypted logins and passwords. Although some proxy networks claim to only use 'safe' servers, due to the 'anonymous' nature of these tools, proxy server safety is impossible to police. Students should be educated to understand that whenever they use a proxy, they risk someone "in the middle" reading their data.

Tips to prevent Proxy Abuse
-Educate teachers to recognize illicit surfing or proxy abuse and report it to the IT dept.
-Educate students about the danger of using proxies.
-Allow slightly more lenient filtering outside of core hours.
-Make sure your AUP covers anonymous proxying and that both students and teachers are familiar with its content. Make it clear that proxy abuse can be tracked to individuals.