Over the weekend, we ve seen a number of Cross Site Scripting worms for Twitter. The most virulent worm is not particularly complex in the vulnerability it is exploiting. The original author? A bored 17-year-old who had nothing better to do over the Easter weekend. Web sites left and right that integrate with Twitter and other networks are asking users to use their services. Many people seem to be making use of them without too many questions, and without any proper means of verifying the integrity of these services.
Source: https://threatpost.com/twitter-worms-arent-only-threat-041409/72509/