Chinese Internet users in China are dealing with a weird redirection of traffic nationwide while accessing any website that makes use of the Great Firewall of China. Facebook users are complaining that when they visit any website containing “Login with Facebook” buttons, they automatically redirect to unrelated websites. The attack is also intercepting a line of JavaScript from the Facebook Connect plugin to redirect Chinese users to unrelated sites as the content passes through China’s national web filters. Similar tactic sounds very similar to the one that the Chinese officials recently used against Github, apparently in response to dissident content posted by the open source service.
Source: https://thehackernews.com/2015/04/hacking-facebook-login.html