ILOVEYOU, sometimes referred to as the Love Bug or Loveletter, was a computer worm that infected tens of millions of Windows computers following its release on 4 May 2000. The worm was mainly distributed through email attachments sent to contacts on an infected system's address book, and is an example of malware using social engineering to aid its spread. Once run, the worm overwrites files with its source code and attempts to spread to other computers.