Browsers, Beware: The Top 5 Creepiest Computer Viruses

 In Blog, Managed IT Service Providers, Managed IT Services, Managed Network Services, Managed Service Provider

This Halloween, it’s not the werewolves, ghouls, and vampires you should watch out for… It’s something much more insidious. Computer viruses have been a major cause for concern ever since they grew out of their original clunky, mischievous form.

Today, they’re capable of toppling uranium plants, sending panic through the Pentagon, and stealing your banking information before you can say “login information.” 

Before you open your next email or download an online program, take a peek under the bed (or behind the screen) for these 5 killer viruses that brought shock and terror to users, devices, and networks across the globe. 


Largely considered one of the most destructive computer viruses of all time, the ILOVEYOU virus terrorized computers across the world in 2000. It originated in the Philippines as an email with the subject line “ILOVEYOU” and contained a seemingly innocent attachment titled “LOVE-LETTER-FOR-YOU.txt.vbs.” When unsuspecting victims opened this literal can of worms, their computers were infiltrated by a Visual Basic script that could overwrite random files, including images, documents, and MP3s.

The worst part was yet to come… Once it had done its work, the ILOVEYOU virus would send itself to all email addresses in the Windows Address Book. It’s estimated that it infected around 10% of the world’s computers, causing $15 billion worth of damage to 45 million users in one day.  


Stuxnet is unique in that it was the first virus specifically designed to infect hardware and alter its functionality. Most physical damage caused to computers is secondary to the software damage, but in the case of this government-created virus, the main goal was to destroy machinery in Iran. 

Spread through thumb drives throughout a uranium holding facility in Iran, Stuxnet caused the centrifuges in the factory to self-destruct. It targeted programmable logic controllers (PLCs), which are used to automate industrial mechanical equipment. After the thumb drive containing the virus was plugged into a computer, it would update the code through the internet, giving the PLC instructions to commence with dangerous processes and give incorrect feedback to prevent alert systems from warning users. 

While it’s not known just how much this virus cost, it is the first example of the CIA using computer warfare to wage battle. 


Mydoom is pretty light compared to the ILOVEYOU virus, but it took its toll on more than 1 million computers during its reign of terror in 2004. It spread quickly as a bounced message, appearing to the receiver as if an email they had sent did not deliver to its target because of an incorrect email address. When users opened the email, it downloaded a code that wormed its way into Outlook contact books and propagated itself to everyone it could get its hands on. 

Once a computer was infected, MyDoom would launch into a full DoS attack, rendering devices and websites unusable by flooding them with an overwhelming amount of data. It even gave search engines a run for their money, as they received millions of automated search requests from infected computers.


You know things are getting scary when federal buildings are worried about keeping themselves safe. The agent.btz virus is sometimes called “the worm that ate the Pentagon,” a tongue-in-cheek commentary on how malware can send shockwaves before its even done its dirty deeds. 

When a virus was found squirming its way into the Secret Internet Protocol Router Network, which is used to send top-secret transmissions to and from the Pentagon, the U.S. Strategic Command disallowed the use of jump drives, external hard drives, and any removable storage media. 

After the success of the StuxNet virus, it’s understandable why there were a few eyebrows raised about whether or not this was an everyday malware or a retaliation attempt from a foreign nation. The Pentagon took every precaution they could think of, including scrubbing code and launching an investigation into what nation was targeting the federal network. While no evidence was released that it was, in fact, a hacking attempt by a foreign spy, it does mark a shift in the government’s involvement in cybersecurity. 


In 2003, Slammer made its way into both the public and private eye as it brought Bank of America, 911 emergency systems, and a nuclear power plant to screeching halt. This true terror of the cybersecurity world made its way to more than 75,000 users within 10 minutes by exploiting database vulnerabilities and rewriting SQL to do foul acts. 

It works by rewriting the computers “to-do list,” called a stack, with a new list of its own. This causes the computer to completely reprogram itself, all the while thinking that it’s just the next step on a list of processes. This made the Slammer hard to initially detect, as devices were not catching the problem until it had already infiltrated the perimeter. 

Once Slammer made its new home in a computer, it generated a new IP address based on the number of milliseconds that have passed since the computer was booted. When it was done, it used this randomly generated address to target its next victim. This process of rewriting and sending out new copies of the virus soon proved too much for even commercial networks to handle, causing the shutdown of ATMs and other corporate machinery. 

Computer Viruses Don’t Have to Be Scary

Don’t let computer viruses spoil your Halloween fun. Invest in end-to-end protection backed by award winning hardware, software, and AV programs to help you stay safe from even the most nefarious computer viruses.

Verus designs, implements and supports networks that meet the highest standards for data, firewall and connectivity security. With Verus Solutions Suite, you can choose the services that best fit your needs and your budget. From antivirus to network monitoring, we’ve got tools that will protect your data from every trojan horse, ransomware, and worm that comes your way.  

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