China's Great Firewall hijacks Faebook's login system

China's Great Firewall has reportedly been consistently intercepting the Javascript module from Facebook Login, which allows third-party sites to authorize users through Facebook infrastructure, for the last three days.

The behavior was first reported on Sunday. A Facebook spokesperson said that it was occurring locally and beyond the reach of their servers. The social media site is probing the situation, reported The Verge.

The attack causes sites using Facebook Login to redirect users to two sites: an open-source software project, wpkg.org or a personal travel blog, ptraveler.com.

Only web users based in China or those accessing the web without a VPN will be affected as the code is intercepted within China's national telecom infrastructure. The attack can also be avoided by disabling Javascript, since the inserted code runs as a Javascript applet.

It's not clear why the Chinese government would want to send users to these sites. However, it's not the first time that China has performed this kind of traffic interception. A similar redirection was used in March to perform a denial-of-service attack on GitHub, apparently in retaliation for dissident content posted through the service.