Hal Roberts

China recently mandated that Green Dam, a client side application that filters pornography and political content, be installed on all computers manufactured in China starting July 1, 2009. One way the application blocks access to sites is to kill the browser window when it tries to visit an offending site. The above video demonstrates that the application is poorly designed such that it can end up killing the browser window every time the user types ‘F’ as the letter in the location window.

downloadable version of the video

What’s happening in the video is GD fails to block falundafa.org the first time it is loaded, so ‘falundafa.org’ gets into the history of the browser. Eventually GD recognizes the offensive content on the sites and kills the whole browser after briefly flashing a ‘you have been filtered’ image. Any time GD flags a site as politically offensive, that url gets entered into a list of urls to trigger a kill-block whenever it is entered into the location bar or window. But that auto-kill-block applies to text brought up in the auto-complete list as well as text in the entry box proper. Since falundafa.org is in both the auto-complete list and in the auto-kill-block list, every time the user brings up the location window and types in ‘f’ to start a url, the location window and current tab are instantly killed.

Presto, China has banned the letter ‘f’!

Full details in our just published ONI report on the tool.

Update: replaced youtube version with local version to support folks blocked from youtube.