W32.Sober-K-mm spreads itself as an e-mail attachment and creates random subject lines and body texts in either English or German, depending on the e-mail addresses it gathers. Subject lines observed so far include "Alert! New Sober worm," "Paris Hilton Sex Videos," "You visit illegal websites" and "Your new Password," according to MessageLabs..
The worm can also generate fake messages that try to fool the recipient into opening the attached .zip file. Some e-mails purport to be from an anti-virus company offering a security patch against a new version of the Sober worm. Others pretend to be from the FBI and include an attachment labelled "indictment."