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Top 5 Computer Viruses Of All Time

What were the five most catastrophic computer viruses ever and how much damage did they cause?

The fact that the internet has become the backbone of modern society means that it has also become a prime target for hackers and crackers around the world. Find out here about the most prominent and catastrophic computer viruses the world has ever seen and discover exactly what made them so damaging.

MyDoom (2004)

This worm spread through email as what appeared to be a bounced message. When the email was opened, the malicious code downloaded itself and scoured the victim’s Outlook address book. Once it obtained email addresses and info from the address book, it spread to the victim’s friends, family and colleagues. By using this method it was able to infect over two million PCs within two hours and caused approximately $38 billion in damages.

SoBig.F (2003)

This was a worm that was able to replicate itself, but it was also a Trojan, as it disguised itself as something other than malware (Malicious Software). This virus was also spread through email and had similar functions as the MyDoom virus where it obtained email addresses. This computer virus “flooded” the inboxes of victims, rendering them useless. It also brought freight and computer traffic in Washington, D.C. to a halt, grounded Air Canada and slowed down computer systems at many major companies.

I LOVE YOU (2000)

Posed as an innocent looking email attachment labeled “I Love You”. When opened, it unleashed a malicious program that overwrote the users’ image files. It was designed to steal Internet access passwords. 500,000 PCs were infected by this and it caused nearly $15 billion in damages in just under nine hours.

Code Red (2001)

All Operating Systems have vulnerabilities. Code Red was designed to exploit a vulnerability in Windows 2000 and Windows NT systems. This worm was able to deface and take down some websites, most memorably the website and forced other government agencies to temporarily take down their own public websites as well. This worm spread by randomly selecting 100 IP addresses at a time, scanning the computers for the Windows 2000 or NT Operating System and then spreading only to those computers. This caused $2.6 billion in damage and infected one million PCs.

Slammer (2003)

This Internet worm caused a denial of service (DoS) on some Internet hosts and dramatically slowed down general Internet Traffic. It worked by releasing a deluge of network data bringing many servers to a near halt. As it began spreading throughout the Internet, it doubled in size every 8.5 seconds. It selected IP addresses at random to infect, eventually finding all susceptible hosts. Among its list of victims was Bank of America’s ATMs, a 911 emergency response system in Washington State, Continental Airlines and a nuclear plant in Ohio. This infected 200,000 PCs in just 10 minutes and caused $1.2 billion in damages.