Top 10 Computer Viruses of all Time

The Internet has been a revolutionary technology that changed the world and the hackers have been trying to crack the vulnerabilities that they can use for their own gains. They also pose a threat to the internet.Here are the top 10 viruses and worms that impacted the world.

1. Melissa

Davil L Smith in 1999 created a virus called Melissa based on Microsoft Word Macro.The virus propagated through the email messages with a attachment called ”Here is that document you asked for, don’t show it to anybody else.”When the victim clicks the attachment, the virus replicates itself by sending it to top 50 emails on the contact list.

2. ILOVEYOU

Developed in Philippines it propagated through Internet Relay Chat and by emails in a Visual Basic Script attachment by tricking them to believe the email is from a secret admirer.It hid several copies of the file in victims computer and replaced several files in the Hard disk of itself.It downloaded a virus file Win-BugsFix.Exe from the internet and executed it.The file would then email the passwords to the Hackers email address.The worm accounted for over 10 billion in damages.

3.  Code Red & Code Red II

Found in 2000, Created a backdoor in the victims computer and used it to control remote access to carry of various kinds of attacks including Denial of Service using the victims computer. The virus used a vulnerability in Windows 2000 and Windows NT , where the buffer overwrites the adjacent memory if the buffer overflows due to too much information.

4. The KLEZ

The Klez debuted in late 2000 , lasted fo several months and spread using spoofed emails to the contact list in the victims computer.It could either act as a Trojan Horse,virus or a worm.The virus made the operaating system inoperable or sometimes could even stop a antivirus program.

5. Nimda

Nimda, Admin spelled backwards, found in 2001 the virus spread rapidly and attacked major internet servers and created backdoors in the victims computer for Denial of Service Attacks.It spread through various methods including emails and gained similar level of access as the person logged into the computer, i e as a administrator or limited user.It bought down many network services by taking up and depleting its resources.

6. SQL slammer/Sapphire

Found in January 2003, the Virus bought down several major web services including Bank Of America ATM services and Continental Airlines and caused more than 1 billion in losses.It spread rapidly doubling every few seconds and infecting half of internet backbone servers in fifteen minutes before the antivirus software’s caught it.

7. MyDoom

Created in 2004 , created a backdoor in victims computer and spread through spoofed emails and peer to peer networks. MyDoom had 2 triggers , where one trigger command was used to command it to Denial of Service attack and the second trigger was used to command stop distribution of the virus.

8. Sasser and Netsky 

Created by  a 17-year-old German named Sven Jaschan , though both programs behaved in different ways, the similarity in coding led in finding out the person. Sasser virus attacked a windows vulnerability and propagated by attacking the victim computer and scanning potential IP addresses for other vulnarable computers for downloading the virus. It even made the victim’s computer difficult in shutting down their computer.   Netsky moves through email’s and windows networks through a attachment and causes a Denial of service attack in taking down web services.

9. Leap-A

Malicious program designed specifically for attacking vulnerability in Mac. Found in 2006, it uses the iChat program to send out messages to all the contacts in the contact list and propagating further to other vulnerable Mac computers. The virus sends out a corrupted file which looks like a jpeg image file attached through the iChat application.

10. Storm Worm

Storm Worm is a Trojan horse program.Found in the year 2006 and called with different names,storm worm is used to carry different payloads of programs in it.This was also used to create Botnets which is used for remote control of the victims computer for sending out spam mails.It was found that more than 200 million emails were infected in carrying the Storm Worm virus in  a span of few days.The Worm was downloaded off the links disguised of the recent events taking place at the time, like the Beijing Olympics or Earthquake in China.