MoneyINC Logo
Years of

The 10 Worst Computer Viruses of All-Time


Few people can deny that computers have been a wonderful invention on so many levels. They have made our lives easier and have connected the world in countless ways. At the same time, they are prone to causing us tremendous headaches, particularly when someone does something to intentionally sabotage all of the work that you have done. This is the case with computer viruses. While some are relatively harmless, others can be particularly destructive. Let us take a look at the 10 worst computer viruses of all time.

10. Melissa

Melissa was actually created back in 1999 by David Smith. He designed this using a macro in Microsoft Word. The virus itself would be spread through email messages that were sent from one user to another. He actually named the virus after an exotic dancer that he new from Florida. The virus worked by tempting those who received the message to open a document that they have asked for. It even states that you are not to show it to anyone else. One opened, the virus would then replicate itself 50 times and get sent automatically to contacts from the recipient's address book. It would end up clogging entire emails systems because of how many emails were being sent out. Smith ended up being convicted after a long trial and received 20 months in prison.

9. I Love You

This virus actually hit the Internet about a year after Melissa did. It came from the country of the Philippines. This threat actually came because of. worm. It was a program that could stand on its own and was able to replicate itself. The I Love You virus actually made it4s way through the Internet via email. It was inside a message that appeared to be a love letter from another person. There would be an attachment to the email. If you were to open that, you would be infected. This would create a host of problems, such as being copied several times and hiding on the hard drive. It would replace certain files with copies of the virus. The problems just kept coming. Nobody really knows who created this virus, but it caused roughly $10 billion in damages before it was finally shut down.

8. The Klex Virus

With this virus, a new bar was reached. It came out in 2001 and various forms of the virus would hit the Internet and wreak havoc for months. The worm would infect a computer via an email message. This would then replicate itself and be sent to almost everyone in the address book. This made it similar to Melissa, but there were twists. This worm could actually make the computer inoperable. It would even detect anti-virus software and disable it. The evil nature of this one is that certain hackers actually intercepted the virus, made it even stronger, and sent it out again. One of the things that caused so many people to open the email is that the 'from' field of the message was manipulated to contain names of actual people in the contact book.

7. Code Red and Code Red II

Both of these worms ended up making their ugly appearance in 2001. They would exploit the victim's operating system. Windows 2000 and Windows NT machines were particularly vulnerable. It created a buffer overflow problem, which meant that the computers would end up receiving much more information than it could handle at once. This would cause it to start overwriting the memory. If your machine was affected, the computer would no longer obey your commands. You essentially lost control of the computer. Microsoft would have to create patches to kill this virus.

6. Nimda

Here is a virus that was also created in 2001. Nimda spells admin backwards and ended up being the fast moving virust of all time. It would take only 22 minutes after it was introduced for it to already becoming the number one virust from the perspective of the attacks that were reported. Internet servers were the primary target of this worm, as its purpose was actually to bring all traffic on the Internet to a crawl. It moved via email and several other methods. People were not even away that their machines were infected.

5. SQL Slammer/Sapphire

This virus would come out in 2003 and was designed to impact Web servers and it spread across the global Internet system. At the time, countless networks were simply not prepared for the attack that this particular virus would unlease. Even the entire ATM system at Bank of America would crash, and Seattle would see its 911 system come to a crashing halt. Continental Airlines at the time would have to cancel several flights because of issues with their electronic ticketing system. This virus would end up costing more than $1 billion in total damages before a fix was actually written.

4. MyDoom

This virus worked by creating a backdoor into the computer's operating system of the victim. There were two triggers for this virus, both occurring in February of 2204. The second part of the virus would actually impact Internet search engines. At the time, it was estimated that one out every 12 messages being sent by email were infected with the virus.

3. Sasser and Netsky

This is the third worst computer virus of all time, and it was really a doozy. This one was actually created by a German who was only 17 years old at the time. He actually created two different programs and released them over the Internet. This virus did not need email in order to spread. Once it was on a computer, it would impact other systems, making them vulnerable. It would get in through the Internet.

2. Leap-A/Oompa-A

This is the only virus on the list that specifically targets Mac computers. It was created in 2006. It made use of the iChat instant messenger program to infect the computers of its victims. It would then search through the iChat contacts to send a message to everyone on their list.

1. Storm Worm

This is the worst virus and it was created in 2006. It got its name because the subject of the email referenced a storm that was battering Europe. It would basically turn the computer into a zombie or bot. The infected computer could end up being accessed by another person who was behind the attack itself. These are the 10 deadliest computer viruses of all time. Make sure that your system is up to date with its anti-virus software in order to combat possible future attacks.

Dana Hanson

Written by Dana Hanson

Dana has extensive professional writing experience including technical and report writing, informational articles, persuasive articles, contrast and comparison, grant applications, and advertisement. She also enjoys creative writing, content writing on nearly any topic (particularly business and lifestyle), because as a lifelong learner, she loves to do research and possess a high skill level in this area. Her academic degrees include AA social Sci/BA English/MEd Adult Ed & Community & Human Resource Development and ABD in PhD studies in Indust & Org Psychology.

Read more posts by Dana Hanson

Related Articles

Stay ahead of the curve with our most recent guides and articles on , freshly curated by our diligent editorial team for your immediate perusal.
As featured on:

Wealth Insight!
Subscribe to our Exclusive Newsletter

Dive into the world of wealth and extravagance with Money Inc! Discover stock tips, businesses, luxury items, and travel experiences curated for the affluent observer.
linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram