Facebook, one of most popular social networking sites has been available to a critical XSS, allowing the hackers to install malicious scripts. Researchers who detected this vulnerability also posted a screenshoot demonstrating the problem. One of most recent incidents were serving malware and live exploit URLs, due to vulnerable web applications, introducing Zlob trojans in the form of fake video codecs, and was initially traced back to infrastructure provided by the Russian Business Network. The security folks at Facebook have been notified and as it seems the Facebook team responded very quickly and fixed the issue immediately!