There are a few different types of computer viruses. The typical virus is the virus explained in the previous section. There are also email viruses, worms, and Trojan horses.
Another notable email virus was called the ILOVEYOU virus, which infected computers on May 4, 2000. An email was sent out with a virus infected attachment. The recipient double-clicked on the attachment, allowing the virus to execute—automatically sending the attachment to the recipient’s entire address book. The effects were disastrous as well—destroying files and programs on the recipient’s computer.
are pieces of code that use computer networks and security holes to replicate
themselves and wreak havoc on systems. Worms are computer programs
that are able to copy themselves from machine to machine, through computer
networks. In July 2001, the Code Red Worm copied itself over 250,000
times in a nine hour span. It specifically attacked servers of Windows
NT 4.0 and Windows 2000 running Microsoft Internet Information Server.
The worm searched for unsecured servers, and copied itself to them.
The Code Red Worm was made to have three major effects:
• Replicate itself for the first twenty days of infection
• Replace the victim’s web pages with a page stating, “Hacked by Chinese.”
• Orchestrated an attack on the White House web server in an attempt to overwhelm it.
Trojan Horses are actually normal computer programs. A Trojan Horse pretends to be a regular downloadable program, such as a game, but actually does something different—most likely does damage to a computer, like erasing a disk. This is different from a regular virus, because it doesn’t attempt to reproduce itself. Trojan Horses do not affect a great number of people because they are discovered quickly.