Apr 14 2009

Twitter Attacked by Powerful Worm

Twitter, the 3rd biggest social network after Facebook and Myspace was hit over the weekend by powerful, self-replicating attacks that caused people to flood the micro-blogging site with tens of thousands of messages simply by viewing booby trapped user profiles.

The worm attacks began early Saturday morning and were the result of XSS, or cross-site scripting, bugs in the Twitter service. They caused those who viewed the profiles of infected users to post tweets promoting a site called StalkDaily.com. Victim profiles were then altered to include malicious javascript that infected new marks. Over the next 36 hours, at least three similar worms made the rounds, causing Twitter administrators to delete more than 10,000 tweets.

Twitter’s inability to quickly contain the mess prompted some security watchers to criticize Twitter for not being more on top of it. According to this postmortem from the Dcortesi blog, the attacks exploited gaping holes that allowed users to insert tags in the URLs of Twitter users’ profile pages that called malicious javascript from third-party web servers.

As is frequently the case with XSS-based attacks, the worm was unable to prey on those using the NoScript add-on for the Firefox browser.

Twitter’s security team was able to block the attack for a while, but a new assault that made use of “mildly obfuscated” code soon defeated the countermeasure, raising the possibility that it was based on the detection of attack signatures rather than fixing the underlying bug that allowed the XSS vulnerability in the first place.

Source: The Register