Keim-web.com

It seems as if these warnings never end. Be careful what email attachments you open—even if they look like they are replies to the email you already have in your system. It could be a new virus/worm.

Trend Micro representatives say the virus disguises itself as legitimate e-mail by replying to an existing e-mail message in your in-box, not simply by drawing on addresses in your address box.

The company provided an example of a legitimate e-mail message sent to an infected user, concerning something business related, that is answered by the worm with the message, “I’ll try to respond as soon as possible. Take a look to [sic] the attachment and send me your opinion!” Users will often click on this attachment, since it appears to come from a person they know, Trend Micro said.

Most anti-virus software allows you to update its virus definitions for free. Now would probably be a good time to do that. Read more about the worm at PCWorld.com: Leading antivirus vendors post inoculations for newest pest