Hit numerous computers in 2000 when it was sent as an attachment to an email message with the tempting text “ILOVEYOU” in the subject line. The virus was also altered to appear in email messages with the subject line FWD: JOKE. The ILOVEYOU virus came with the nice little message “kindly check the attached LOVELETTER coming from me,” and if the user opened the attachment in any of these messages, the malware was executed, sending a copy of itself to every address listed in the user’s Microsoft Outlook address book.

The ILOVEYOU virus and many of its variants have been estimated to have targeted tens of millions of users over the life span of these viruses, costing billions of dollars in damage and service disruption.

See Also: Electronic Mail or Email; Malware; Virus.