Mass-mailing worm in fake Twitter account invite

From Symantec Corporation: "Last month we reported that spammers had used Twitter as bait to lure innocent victims into a phishing trap, and now we're seeing a wave of fake Twitter invitations that come carrying a mass-mailing worm. The observed messages appear as if they have been sent from a Twitter account; however, unlike a legitimate Twitter message, there is no invitation URL present in the body. Instead, the user will see an attachment that appears as a .zip file that purportedly contains an invitation card. Invitation Card.zip is the name of the malicious attachment, and it is being identified as W32.Ackantta.B@mm, which was first discovered in an e-card virus attack in February. W32.Ackantta.B@mm is a mass-mailing worm that gathers email addresses from the compromised computer and spreads by copying itself to removable drives and shared folders"