The Koobface worm, which previously had mainly affected MySpace and Facebook, is now infiltrating Twitter, Kaspersky Lab researchers said Tuesday. Infected accounts sent tweets containing a link to a URL that masqueraded as a video site, but actually contained malicious JavaScript. Mac or Linux users who clicked on the link were redirected not to the malware site but to adult sites. Twitter said over the weekend that it will shutter accounts known to be distributing the worm. — DK