The “Love Letter” worm is a malicious VBScript program that first appeared May, 2000, which spreads in a variety of ways. As of 5:00 pm EDT(GMT-4) May 8, 2000, the CERT Coordination Center received reports from more than 650 individual sites indicating more than 500,000 individual systems were affected. In addition, several reports of sites suffering considerable network degradation as a result of mail, file, and web traffic generated by the “Love Letter” worm.
You can be infected with the “Love Letter” worm in a variety of ways, including electronic mail, Windows file sharing, IRC, USENET news, and possibly via webpages.
View the rest of the original CERT advisory.