The email virus that spread through Microsoft Word macros in 1999 was Melissa.
Melissa first appeared on March 26, 1999, as an infected Word document distributed through online newsgroups and email. When a recipient opened the document with macros enabled, the virus used Microsoft Outlook to send copies of itself to the first 50 addresses in the victim’s address book. That mass-mailing behavior quickly overloaded corporate email systems.
The malware was a macro virus rather than a conventional executable file. Its Visual Basic for Applications code copied itself into Word’s template system, allowing it to infect documents and activate when those documents were opened. It primarily affected Microsoft Word 97, Word 2000 and Outlook 97 or 98 environments.
Melissa is commonly confused with ILOVEYOU, another famous email-borne outbreak that appeared in 2000, or Nimda, which spread in 2001. Melissa’s distinguishing features were its Word document attachment, macro-based infection and automatic emailing through Outlook. Its author, David L. Smith, was later arrested and prosecuted.