In this day and age it's hard to believe that anyone would open an attachment or clink on a link in an e-mail that they were unsure of, but it happens. So be careful because there is a new fast-spreading e-mail worm circulating. It's the first large outbreak of this type in nearly a decade.

The worm appears in e-mail messages with the subject "Here you have," and contains what seems to be a link to an Adobe PDF file. In fact the link takes the victim to a Web page hosted on the members.multimania.co.uk domain that then tries to download a screensaver (.scr) file. If the user agrees to install the file, he is then infected by the worm, which mails itself to his e-mail contacts. The body of the e-mail typically says something like, "Hello... this is the document I told you about, you can find it here." Because the worm is spreading via contact lists, the e-mail often comes from someone the victim knows.

he worm is similar to the ILoveYou and Anna Kournikova worms, which spread in 2000 and 2001, and is a type of malware that has not been a major problem since around 2002, according to David Cowings, a senior manager with Symantec Security Response. "It looks like we've had a resurgence of mass-mailing worms," he said.
In fact, "Here you have" is the same subject line used by the Anna Kournikova worm.