ILOVEYOU

ILOVEYOU, sometimes referred to as the Love Bug or Loveletter, was a computer worm that infected over ten million Windows personal computers on and after May 5, 2000. It started spreading as an email message with the subject line "ILOVEYOU" and the attachment "LOVE-LETTER-FOR-YOU.TXT.vbs." At the time, Windows computers often hid the latter file extension ("VBS," a type of interpreted file) by default because it is an extension for a file type that Windows knows, leading unwitting users to think it was a normal text file. Opening the attachment activates the Visual Basic script. First, the worm inflicts damage on the local machine, overwriting random files (including Office files and image files; however, it hides MP3 files instead of deleting them), then, it copies itself to all addresses in the Windows Address Book used by Microsoft Outlook, allowing it to spread much faster than any other previous email worm.

Onel de Guzman, a then-24-year-old resident of Manila, Philippines, created the malware. Because there were no laws in the Philippines against making malware at the time of its creation, the Philippine Congress enacted Republic Act No. 8792, otherwise known as the E-Commerce Law, in July 2000 to discourage future iterations of such activity. However, the Constitution of the Philippines prohibits ex post facto laws, and as such de Guzman could not be prosecuted.