The Most Dangerous Computer Viruses in History

Here are some of the most dangerous computer viruses in history:


Jerusalem - 1987


This is one of the first MS-DOS viruses in history that caused enormous destructions, affecting many countries, universities and companies worldwide. On Friday 13, 1988 the computer virus managed to infect a number of institutions in Europe, America and the Middle East. The name was given to the virus after one of the first places that got "acquainted" with it - the Jerusalem University.





Along with a number of other computer viruses, including "Cascade", "Stoned" and "Vienna" the Jerusalem virus managed to infect thousands of computers and still remain unnoticed. Back then the anti-virus programs were not as advanced as they are today and a lot of users had little knowledge of the existence of computer viruses.


Morris (a.k.a. Internet Worm) - November 1988


This computer virus infected over 6,000 computer systems in the United States, including the famous NASA research Institute, which for some time remained completely paralyzed. Due to erratic code, the worm managed to send millions of copies of itself to different network computers, being able to entirely paralyze all network resources. The damages caused by the Morris computer virus were estimated at $96 millions.


To be able to spread, the computer virus used errors in such operating systems as Unix for VAX and Sun Microsystems. The virus could also pick user passwords.


Solar Sunrise - 1998


A decade later the situation didn't change, in fact it even got worse. Using a computer virus, hackers, in 1998, penetrated and took control of over 500 computer systems that belonged to the army, government and private sector of the United States. The whole situation was dubbed Solar Sunrise after the popular vulnerabilities in computers that run on the operating system called Sun Solaris. Initially it was believed that the attacks were planed by the operatives in Iraq. It was later revealed that the incidents represented the work of two American teenagers from California. After the attacks, the Defense Department took drastic actions to prevent future incidents of this kind.


Melissa - 1999


For the first time computers got acknowledged with Melissa computer virus on March 26, 1999, when the virus shut down the Internet mail system, which got blocked with e-mails infected by the worm. It is worth mentioning that at first Melissa was not meant to cause any harm, but after overloading the servers, it led to serious problems. For the first time it spread in the Usenet discussion group alt.sex. Melissa was hidden within a file called "List.DiC", which featured passwords that served as keys to unlocking 80 pornographic websites. 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. Its name comes from a lap dancer that the programmer got acknowledged with while in Florida. After being caught, the creator of the virus was sentenced to 20 months in federal prison and ordered to pay a fine of $5,000. The arrest was made by a team of representatives from FBI, New Jersey State Police and Monmouth Internet.


Melissa had the ability to multiply on Microsoft Word 97 and Word 2000, as well as on Microsoft Excel 97, 2000 and 2003. In addition, the virus had the ability to mass-mail itself from Microsoft Outlook 97 and Outlook 98.