Most Deadly Computer Viruses of All Times

Every Computer user has faced a computer virus attack in his/her lifetime. That’s why the first thing we do after installing an operating system is to install an Antivirus Program on our computer. Don’t we? So in this article we are not going to discuss about all antivirus programs and which one should you use. Instead of that,I am going to write of the most deadly computer virus of all times in the history of Computer Viruses.

Now Let’s Start our Journey of Viruses:-

Melissa:- The Virus created in 1999 by David L. Smith based on Microsoft Word macro. This Virus tempts its recipients to open a document with an e-mail message like "Here is that document you asked for" Once activated, the virus replicates itself and sends itself out to the top 50 people in the recipient's e-mail address book.

ILOVEYOU:- The virus with a sweet name but of nasty nature created by Onel de Guzman of the Philippines . This virus spread in the same way like Melissa .It copied itself several times and hid the copies in several folders, added new files to the registry keys, replaced several different kinds of files with copies of itself, sent itself through Internet Relay Chat clients as well as e-mail,it downloaded a file called WIN-BUGSFIX.EXE from the Internet and executed it. Rather than fix bugs, this program was a password-stealing application that e-mailed secret information to the hacker's e-mail address. According to studies , It is assumed that this virus had caused damage of $10 billion.

The Klez Virus:- This Virus established new standards in the virus technology due to its advanced features . The virus infect a computer through an e-mail message and replicates itself and then sent itself to people in victim address book .Moreover it can also use a contact name from the victim address book in From field to send itself .so as to tempt recipient to open that email. This is called email spoofing.

Code Red:- This virus emerged in 2001 exploits the vulnerabilities of operating system mainly found in Windows 2000 and Windows NT . The vulnerability was a buffer overflow problem, which means when a machine running on these operating systems receives more information than its buffers can handle, it starts to overwrite adjacent memory. This virus creates a backdoor in computer so that a remote user can access the infected computer and also can use it to commit crimes.

Nimda:- Nimda virus when spelled backwards become admin emerged in 2001 spread rapidly over the internet at that time . This virus create a backdoor and give the attacker same level of functions of the account which is currently logged in . If the victim is logged in account with limited functions, the attacker would also have limited access to the computer's functions. On the other hand, if the victim was the administrator for the machine, the attacker would have full control.

Slammer Virus:- Slammer Virus also Known as Sapphire Virus emerged in 2003 was created to attack mainly web servers . It used a SQL program to attack several important systems like The Bank of America's ATM service crashed, the city of Seattle suffered outages in 911 service and Continental Airlines had to cancel several flights due to electronic ticketing and check-in errors. The estimated damage caused by this virus was of $1 billion. It mainly effected South Korea By cutting it off internet

MyDoom Virus:- MyDoom Virus like another worm searched victim computers for e-mail addresses as part of its replication process. It also use search engine to found emails and used the email addresses found in the search results. Search engines like Google began to receive millions of search requests from corrupted computers. These attacks slowed down search engine services and even caused some to crash.

Leap-A/Oompa-A Virus:- This Virus is special because it’s the Mac Virus instead of being a PC Virus and show that even a Mac computer could be infected with a virus . It uses the iChat instant messaging program to propagate across vulnerable Mac computers. After the virus infects a Mac, it searches through the iChat contacts and sends a message to each person on the list. The message contains a corrupted file that appears to be an innocent JPEG image.

This is a guest post by Gagandeep Singh who is working for a Desktop and Laptop Computer Repair Company in Clermont, Florida. South Lake Computers has the most personalized computer repair & service experience, while avoiding the confusing ‘techno-babble’ you may hear elsewhere.


  1. thanks...that was very informative

  2. Very informative indeed

  3. I would love to see more details in this post, i was very disappointed in the information i found for my class.

  4. Not more say............ Just say perfect. Continue....

  5. one of the worst ive found is the trojan vundo,bad thing,i have it right now and its ripping my com apart

  6. Linux solves all these problems....

  7. trojan horse is killer


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