Slipping Through the Filter: The Effectiveness of Web Filtering

In January of 2010, Google went public with information that Chinese hackers had attacked Gmail accounts of human rights activists in December of 2009. As a result, Google announced that it would no longer comply with Chinese government regulations that required the censoring of search results that are related to sensitive political and social issues. But just how easy is it to filter Internet content?

Back in May of 2009, the Chinese government also directed that any PCs sold in China would be required to have a program called the “Green Dam Youth Escort Web” filter installed. However, this announcement was plagued with controversy from several areas, according to two researchers at Swansea University in Wales.

When it was announced, security researchers claimed the program contained vulnerabilities that would expose users the security threats. The U.S. government claimed that the requirement should be revoked on free trade principles and advocates of free speech said the government could use the technology to block websites and monitor users’ activities online.

The Chinese eventually delayed the roll out of the technology except in public access locations, such as schools and cyber cafes. China is also not the only country to be involved in filtering Internet content.

According to the OpenNet Initiative, around 35-40 countries actively filter Internet access. Iran allegedly blocked access to social networking sites like YouTube, Facebook and Twitter and monitored Internet access to track protestors down following the allegedly fraudulent re-election of President Mahmoud Ahmadinejad.

Web filtering comes in a variety of forms, with varying levels of complexity and effectiveness. The easiest format for web filtering is creating blacklists of IP addresses and URLs. However, there are several flaws in this most basic method, including the unintentional blocking of legitimate sites and the need to constantly update blacklisted sites and IP addresses.

Another type of web filtering is content filtering, which does not require an established blacklist and the filtering is dependent upon individual web pages rather than entire websites. However, the technology can slow data requests and requires a well developed AI level to determine what content is appropriate or inappropriate on websites.

Despite the options available to states to limit access to a variety of Web content, individuals often find ways to circumvent Web filters. There are a number of proxy tools available, utilized by users in China, that offer uncensored Web access and URL blacklists can be circumvented by going to the IP address of the server.

Although skilled users can often circumvent government restrictions, the majority of web users do not have the technical skill to do so. So while Web filtering will not stop the determined user, it is effective for the majority of a nation’s citizens.

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2. Two Schools in China Implicated in Operation Aurora Attacks
3. Millions of Chinese Don’t Use Anti-Virus
4. Researchers Develop Software to Stem DDoS Attacks
5. US Criticizes Australia’s Attempts to Censor Cyberspace