Melissa virus
The Melissa virus was an e-mail virus released on March 26, 1999. The virus spread so rapidly that e-mail systems were overloaded by the virus propagating itself and became the fastest spreading virus to date.
The virus would infect a machine with an e-mail message. The e-mail message's subject indicated that the message contained a file that the user had requested. After the attachment is opened, the virus infects the machine and spreads to other e-mails through macros in Microsoft Word 97 and Microsoft Word 2000 files. These macros mass-mailed new copies of themselves to the first fifty addresses in the infected user's address book if they are using Microsoft Outlook 97 or 98. While the virus itself was not initially designed to be malicious, because it overloaded e-mail servers it did cause damage.
The author was found to be David L. Smith of New Jersey, who named the virus after a Miami stripper. He received twenty months in federal prison and a $5000 fine. It is estimated that the virus reached thousands of computers in hours with damages estimated at more than $80 million.