Virus
It has been said that the World Wide Web is the second best invention ever made. However, just like other man-made inventions, the Internet has its own menace. Foremost of the known menace is the virus.

A commuter virus is an executable piece of code that infects or attached it self to others s commuters.

Most of the computer viruses are considered malicious which infects and delete files. It is estimated that one in every e-mails circulating contains viruses. Virus are growing and propagating more effectively these days.
Viruses and their damages:

Love Bug

Love Bug is computer virus infects information system has caused a damaged of 5.5 billion US Dollars. Love Bug is also know as the “I Love You Virus”. It is estimated that 10 percent of all computers connected to the Internet were infected during the time of this virus.

Melissa

This virus was detected on March 29, 1999 and shut down Internet mail systems that got clogged with infected e-mails. It is designed for harm and can mass e-mail itself through Microsoft Outlook 97 or 98. This virus reached a damaged of 1.2 billion US Dollars.

Nimda

It has disrupted many of Internet users across Asia, United States and Europe. Nimda got its name from the backward spelling of “Admin”. Just like Code Red virus, it infects computers and slows down the performance of the Internet. Nimda is designed to propagate quickly among personal computers. However, it does not erase files. It spreads itself with the attachment named REDME.exe. Nimda is the first worm the modified websites and used normal end user machines to search for other vulnerable websites. It infects Windows 95, 98, NT4, ME and 200 users. It infected $370 million worth of damage.

Code Red

The other popular term for this virus is I-worm or Bady. This is a self-propagating virus and produced another variant called Code Red II. It takes advantage of a hole in the Microsoft Internet Information Server or IIS web software. However, this virus does not infect Windows 95, 98 and ME.

The difference between the original Code Red to Code II is that Code Red II installs a backdoor into the systems it infects. The Code Red virus cost $ 2.6 billion worth of damages world wide.