The first major outbreak of these was the W97M.Melissa Word macro virus. A recent worm, the 911 Worm, has been listed that scans Windows systems for shared drives and attempts to install itself in those shares. Any system receiving e-mail with attachments. The most common of theses viruses and worms use Microsoft Outlook, Outlook Express, or Exchange to spread.
Damage ranges anywhere from simply re-mailing itself to destroying data on infected systems.
Special scripted commands could send personal information about you to an unknown address. Do not open attachments to e-mail messages that you are not expecting, especially if they are executable files. If they are Word documents, be sure to have macro protection turned on and pay attention to it when the Macro Detected dialog box pops up. Do not allow unexpected macros to run. Infection from attachments can be avoided by not double-clicking on the document or .exe file even if sent by a trusted source.