http://www.cert.org/advisories/CA-99-04-Melissa-Macro-Virus.html
The virus tries to propagate itself through an email subject line of
"Important Message From." It contains an attachment, and if you open the
attachment, it will attempt to infect your system by exploiting a hole in
the Microsoft Word macro warning option. A patch for that hole is
available at
http://www.microsoft.com/security/bulletins/ms99-002.asp
If you have Microsoft Outlook installed on your system, it will try to
propagate itself by mailing itself to addresses in your address book.
Sandra Unger