The Top 10 Worst PC Viruses of All Time

Viruses have been around for decades and they are created sometimes as a prank but other times to create destruction. Back in the 80s computer viruses were spread by humans the virus was stored on a disk and distributed by humans. When the internet became popular the spread of computer viruses became a real problem.

The Top 10 Computer Viruses

The Melissa Virus was created in 1999 and was based on a Microsoft Word macro. It spread through an email message attachment. When the attachment was clicked the virus replicated and went out to the top 50 people in your contact book. This meant the virus spread very quickly. It caused problems in the US to the government and the private sector. The creator of the virus was sentenced to 20 months in jail and a $5,000 fine.

The ILOVEYOU virus was released in 2000 and was a worm written in Visual Basic Scripting which was self replicating. The virus travelled via email and instant messaging clients with the subject line saying it was from a secret admirer. The virus was able to copy itself and hide in different folders on the computer’s hard drive. New files were created to the registry keys the virus was able to steal passwords and email them to the hackers email address. Apparently the ILOVEYOU virus caused $10 billion in damages.

The Klez virus introduced in 2001 again spread through email messages. This one was particularly clever and used spoofing which made the virus email look as if it was coming from a person in your address book. It was a nasty virus which could leave your machine unusable. The virus was many things and could be a worm, Trojan horse, it could disable virus scanning software and masquerade as a virus removal software. This virus demonstrates how important it is to invest in internet security antivirus software.

The Code Red and Code Red II worms appeared in 2001. If your machines was infected with the Code Red II worm a remote user was able to control your computer via a backdoor to access all of its information and commit cyber crimes. Windows NT machines were affected by Code Red worms which caused them to crash. Microsoft eventually released a security patch which prevented your computer from infection however if you already had a virus you needed buy antivirus software to remove it.

The Nimda Virus was another from 2001 which spread extremely quickly. It was designed to attack internet servers to bring internet traffic to a standstill. This virus also attacked computers and spread through email. It also created backdoors which allowed the creators of the virus to take control of the machine.

The SQL Slammer virus hit in 2003 and was designed to attack web servers. This virus brought down The Bank of America’s ATM service and Continental Airlines had to cancel flights due to electronic ticketing problems. This virus spread so fast in fifteen minutes the virus had infected nearly half of the servers that act as the pillars of the Internet.

The MyDoom virus was another virus that created backdoors on victim’s machines. It caused problems for search engines by sending search requests and using email addresses found in results. Search engines received millions of searches from corrupted machines which slowed it down and caused search engines to crash.

The Sasser virus attacked vulnerable computer systems and made it difficult to shut your computer down without cutting the power. The virus spread over the web and was downloaded onto your machine.

The Netsky virus spread through email it created a denial of service (DoS) attack this caused systems to collapse. The Sasser and Netsky virus were created by the same person a 17-year-old German named Sven Jaschan, who luckily didn’t serve any jail time due to his age.

The Storm Worm a Trojan horse from 2006 was named this because email messages carrying the virus had a subject line “230 dead as storm batters Europe.” The virus allowed hackers to take over computers and send spam. The virus spread through the downloading of fake links to news stories and videos with the subject line changing to reflect current topical news events. This virus has said to have been detected on more than 200 million emails.