Most dangerous computer viruses

Computer viruses have a relatively short history by the damages caused by some of the most dangerous viruses pushed cyber-experts to open a chapter that includes a huge database on computer viruses and the cost of damages caused along with companies, government and universities highly affected by malware.

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

Jerusalem – 1988

This is one of the first MS-DOS viruses in history that caused enormous destructions, affecting many countries, universities and company 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”, “Vienna” the Jerusalem virus managed to infect thousands of computers while still remaining unnoticed. Back then the anti-virus programs were not as advanced as they are today and a lot of users had little belief of the existence of computer viruses.
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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. There were a number of other interesting ideas used by the virus – for example it could pick user passwords.

Solar Sunrise – 1998

A decade later the situation didn’t change, it might have gotten even got worse. Using a computer virus, hackers, in 1998, penetrated and took control of over 500 computers 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 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 it overloaded servers the virus led to unpredictable 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 represented a collaboration of FBI, New Jersey State Police and Monmouth Internet.

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 – May 2000

Using a similar method as the Melissa, the computer virus dubbed “I Love You” 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. After authorities traced the virus they found that a young Filipino student was behind the attack. The young man was released due to the fact that the Philippines did not have any law that would prevent hacking and spreading malware. This situation served as one of the premises for creating the European Union’s global Cybercrime Treaty.

The Code Red worm – July 2001
This 21st century computer virus managed to penetrate tens of thousands of systems that ran Microsoft Windows NT as well as Windows 2000 server software. The damages caused by the Code Red computer virus were estimated at a total of $2 billion. Core Red was developed to use the power of all computers it infected against the official website of the White House at a predetermined date. In collaboration with different virus hunters and tech firms, the White House managed to decipher the code of the Code Red virus and stop traffic as the malware started its attacks.

Nimda – 2001

Shortly after the September 11 tragedy 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 – 2009

The latest and most dangerous virus is the “downadup” worm, which was also called “Conficker”. The computer security company F-Secure stated that the computer virus has infected 3.5 million computers worldwide. This malicious program was able to spread using a patched Windows flaw. Downadup was successful in spreading across the Web due to the fact that it used a flaw that Microsoft patched in October in order to distantly compromise computers that ran unpatched versions of Microsoft’s operating system. But the greatest power of the worm is believed to be the ability of computers, infected with the worm, to download destructive code from a random drop point. F-Secure stated that three of the most affected countries were China, Brazil and Russia.