What is the ILOVEYOU Virus?

The ILOVEYOU virus, also known as Love Bug, was a computer worm that infected millions of personal computers (PCs) around the world beginning in May 2000. The worm spread through e-mails with the subject line “ILOVEYOU” and exploited both technical vulnerabilities and human behavior. After infecting a computer, it sent copies of itself to every contact found in the infected computer’s address book. ILOVEYOU was notable both for the widespread mischief it caused as well as the mainstream media attention it received. The suspected authors of the program were arrested in the Philippines, only to be released when authorities discovered the country lacked any computer security laws under which they could be charged.

Though ILOVEYOU was commonly referred to as a virus, it exhibited behavior more traditionally associated with a computer worm. A worm self-replicates and is usually a standalone program, while viruses may hide in infected files like office documents. Most worms prior to 2000 didn't delete files or cause extensive harm, however; viruses were much more destructive. The ILOVEYOU virus was a kind of hybrid — a self-replicating worm that infected multiple points on a target computer and erased pictures, movies, and other types of files.

E-mail systems all over the world were deluged with infected messages bearing the subject line “ILOVEYOU” beginning on May 4, 2000. By exploiting a quirk in the way certain Microsoft® software handled the display of file extensions, the virus was able to disguise itself as an ordinary text file. This deception, along with the program’s ability to mail itself to contacts within a user’s address book, led many to believe they were receiving a love letter from someone they knew.

While the ILOVEYOU virus infected tens of millions of PCs worldwide, its impact was felt even among Internet users that were not infected. The large amounts of network traffic generated by infected machines mailing the virus to others overwhelmed many mail servers, thus preventing legitimate traffic from getting through. Some large companies and institutions, including the U.S. Senate and the British House of Commons, shut their e-mail systems down completely to deal with the problem. The massive impact of the ILOVEYOU worm led to some of the earliest mainstream media coverage of computer viruses.

Almost immediately after the virus gained global attention, authorities had pinpointed the Philippines as a possible origin of the bug. Filipino police arrested two computer programming students in connection with their investigation, but the two were eventually released when it was discovered the Philippines lacked any laws specifically prohibiting the creation of computer viruses. The country passed such a law just three months after the ILOVEYOU virus emerged, but the suspected authors could not be charged for a crime committed before the legislation went into effect.