A computer virus is a small software which change itself onto some other program. Computer viruses have a relatively short history by the damages caused by some of the most dangerous viruses. When the computer viruses started appearing people didn’t believe in such things, so the virus could damage and destroy a lot more than nowadays before it could be noticed.
Here are some of the most dangerous computer viruses in history ordered by the year of their appearance:
Jerusalem Virus – 1987
This virus caused enormous destructions, affecting many countries, universities and companies worldwide. The name was given to the virus because the Jerusalem University recognized it after being unnoticed for some time.
At the time The Jerusalem Virus was destroying computers there were other viruses breaking through computers too as Cascade, Stoned, and Vienna.
Morris Internet Worm – 1988
The most famous computer that was infected by that virus was NASA research Institute, Due to its code, the worm managed to send millions of copies of itself to different network computers, being able to paralyze all network resources.
Solar Sunrise Virus – 1998
By that time The viruses got worse. Hackers took control of over 500 computers systems that belonged to the army, government and private sector of the United States. It was revealed that the virus was the work of two American teenagers from California.
Melissa Virus – 1999
The virus managed to shut down Internet mail system. At first Melissa was not meant to cause any harm. The original form of the virus was sent through e-mail to different users. Melissa computer virus was developed by David L. Smith in Aberdeen Township, New Jersey. The name Melissa comes from a dancer that the programmer used to know. Melissa had the ability to multiply on Microsoft Word 97 and Word 2000, as well as Microsoft Excel 97, 2000 and 2003. In addition, the virus had the ability to mass-mail itself from Microsoft Outlook 97 or Outlook 98.
I Love You Virus – May 2000
The virus managed to infect millions of computers around the world in just one night. Just like Melissa this computer virus sent passwords and usernames, which were stored on the attacked computers, back to the developer of the virus. A young Filipino student was behind the attack.
The Code Red Worm – July 2001
This virus managed to invade tens of thousands of systems that ran Microsoft Windows NT as well as Windows 2000 server software. Code Red was developed to use the power of all computers it infected against the official website of the White House at a definite date. The White House managed to decipher the code of the Code Red virus and stop its traffic as the virus started its attacks.
Nimda Virus – 2001
This computer virus infected hundreds of thousands of computers worldwide. Nimda was considered to be one of the most complicated viruses, having up to 5 different methods of infecting computers systems and duplicating itself.
Downadup Worm – 2009 was also called (Conficker)
The most dangerous virus. The computer security company F-Secure stated that the computer virus has infected 3.5 million computers worldwide. Downadup was successful in spreading across the Web due to a deficiencythat Microsoft patched. The most affected countries were China, Brazil and Russia.