New Bagle Worms Spreading

New variants of the Bagle email worm have been reported in fairly significant numbers. The two reported variants spread via email using a common name for both the subject line and the attached zip file. (For example, if the Subject line were "Ellen", the attached file would be named "Ellen.zip". Other subject lines identified attempt to convince the recipient the email is one they have sent that's been rejected. For example, "Undeliverable: Ellen" or "Undelivered Mail Returned to Sender".

The first Bagle worm was discovered in January 2004 and a rash of Bagle variants occurred in February and 2004, presumably as a result of the Netsky / Bagle worm wars. The author of the Netsky worm was eventually apprehended and confessed to his crime, though he received almost no punishment in German courts. Over 200 variants of Bagle have been discovered.

Though up-to-date antivirus software can detect and remove known variants of Bagle, there may be a delay before newly spreading variants are detected. Your best defense against Bagle is to avoid opening email attachments received unexpectedly, regardless of their source or the compelling nature of the message.