What computer virus, released in 2000, spread via email with the subject line 'ILOVEYOU'?

The computer virus that rapidly spread in May 2000, primarily through email with the enticing subject line 'ILOVEYOU', is widely known as the Love Bug. This malicious program, also referred to as ILOVEYOU or Loveletter, was a computer worm that exploited human curiosity and trust. Users received an email that appeared to be a love letter from a known contact, prompting them to open an attachment named "LOVE-LETTER-FOR-YOU.TXT.vbs." The ".vbs" extension, often hidden by default in Windows operating systems at the time, made the file appear as a harmless text document.

Upon opening the attachment, the Love Bug executed a Visual Basic Script that immediately began to replicate itself. It would send copies of itself to every contact in the victim's Microsoft Outlook address book, leading to an exponential and rapid spread across global networks. This swift propagation overwhelmed email servers and caused significant disruption, affecting millions of computers worldwide within hours of its release. The virus also inflicted damage on infected machines by overwriting various files, including images and music, with its own code, and attempting to steal internet access passwords.

Originating in the Philippines, the Love Bug was created by a computer science student named Onel de Guzman. The estimated economic damage caused by the virus ranged from $5.5 billion to as much as $15 billion, primarily due to the costs associated with removing the infection and recovering lost data. Its unprecedented speed and impact served as a critical wake-up call for cybersecurity, highlighting the dangers of social engineering and the need for stronger email security practices and public awareness regarding malicious attachments. The incident even spurred legal reforms in the Philippines concerning cybercrime.