15 Of The Most Malicious Computer Viruses Ever

When it comes to our antivirus software, we want to make sure we have the best in order to protect us from the dangers that can come from being online. There are threats like viruses, worms and malware, which scare us and make us ask questions about safety. Recently, people have argued that the antivirus programs which are available to the public do not truly have the requirements to secure your computer and insure defense against malicious cyber activity. Truly, however, antivirus software is up to par and ready for the job, but it isn't the software that has become the problem.

All throughout the world, cyber criminals are becoming more sophisticated and better at what they do. They're learning and inventing new ways to become capable of breaching even the strongest cyber walls. And because of this rise in criminal cyber knowledge, there have been viruses and forms of malware that have amounted to money loss and even threats of deleting all information in systems. Compiled here are fifteen of some of the worst viruses to date. Some of them truly devastated the online community, while others sent scares throughout major companies.


15 Michelangelo

The first virus to make it to the list is known as the Michelangelo virus. Certainly not one of the viruses that made the most damage, but the high scare it caused is what made this virus so popular and made it onto this list. In 1992, the virus was meant to completely disrupt computer systems, but only a few computers were hit, and it barely did any damage. But the virus also brought a threat to detonate a virus on all computers, which was enough to scare everyone at the time. After the virus set off, McAfee saw an opportunity to step in and present their antivirus software. Since then, they have become one of the most popular antivirus companies known around the world. When someone speaks of McAfee, they know to think antivirus.

14 Skulls.A


Skulls.A is one of the famous viruses which caused quite a scare, similar to that of the Michelangelo virus. The difference with Skull.A was the entire virus was meant as a scare tactic in the first place. And it was a virus which affected a specific phone, the Nokia 7610, as well as other SymbOS devices. In 2004, Skulls.A was released and the malware infected phones by changing all of the icons on the screen to skulls, while blocking access to all of the phone's features, apart from calling. And while this malware did little damage to the phones, it is still an undeniably creepy incident that phone users had no control over. Eventually, the entire virus was figured out and the proper corrections were put into place. Unfortunately, malware like this is still discovered, as hackers continue to find ways to manipulate smartphones.

13 Anna Kournikova

Quite a few enticing pictures exist on the internet to lure individuals to a site. Such was the case with one virus that pulled many people in, by tricking them into thinking they would see a naked picture of the famous tennis star, Anna Kournikova. However, in all actuality, it was a virus with the intent to infect and destroy. The financial damages of the Anna Kournikova virus were actually quite minimal. However, because the tennis player was so popular, the virus was too, making it one of the most famous viruses to date. Anti-hackers took time to make sure the virus would never be administered to computers ever again, but the lasting impression of the famously named virus still lingers.

12 Sasser


It's hard to believe that something as simple as a computer virus could infect a system and create problems for very important locations like public transportation and even hospitals. However, it happened in 2004, with a virus known as Sasser. Sasser was a worm, released for the purpose of corrupting machines that had not yet received a certain patch from Microsoft. The virus ended up causing $18 billion in damages, and took out entire hospital networks, methods of public transportation and even airlines. It was an obvious and terrible hit to security that Microsoft never thought possible. The problem was finally fixed, but the aftershock still lingers, with the hopes that a virus such as Sasser never occurs again.

11 Melissa


Viruses and malware sometimes have very strange names. They strike us as odd and leave us wondering why the hacker would have used such a name, like Melissa. Then the reason for the name was discovered. It turned out that the virus was named after a Florida pole dancer. Even though the story behind the name is awkward, the virus itself was not. In 1999, Melissa created a vast majority of issues. The virus was distributed to the first 50 people in a victim's address book. The email would then be opened by other individuals and so on. The virus spread so fast, it infected 20% of all the computers in the world. The final cost of damages was $80 million. However, the virus' creator, David Smith, was indeed captured by the FBI. He was placed in jail for twenty months and had to pay just a $5,000 fine.

10 Storm Trojan


With malicious viruses comes Trojan, which truly battered the computer world during its unfortunate and damaging run. At least 8% of all the infections around the world were the result of Storm Trojan in 2007. It infected various computers and raised its numbers so high within just three days. When the virus was sent, it created what is known as a botnet. Basically, a botnet is a mass of computers used together as part of a group without the computer user's knowledge. Storm Trojan linked users on such a large scale, that it made it almost impossible to catch. It was seen as one of the most intense major botnets in history.

9 Zeus

Criminals working at a higher standard find tools that work best for their needs. One of the worst viruses to be used by a complex criminal entity was distributed as Zeus, or sometimes known to hackers as Zbot. Zeus is a tool which can be purchased for around $3,000. It allows criminals to create their own botnet viruses, allowing access into countless computers, without the user even being aware. The criminals used Zeus to create their own Trojan, and as a result, an amazing $70 million was stolen from victims all around the world from online banking. It was a devastating hit, and many professionals saw it as a new opportunity to increase the means of security. Phishing and keylogging were two of the main means the criminals used to obtain the information, and it's a common technique among web criminals.


8 I-Love-You


People often enjoy receiving love letters. Whether through the mail, or even in an email, the thought that one admirer has for another is intriguing. That's probably what most of the people who opened the ILOVEYOU worm, thought when they received their emails in May of 2000. The ILOVEYOU worm was a virus that was sent out to multiple people to look like an admirer was messaging them, when really, the email held a terrible malware that could infect computers, completely disrupt files and destroy their whole system. The virus spread to up to 10% of all computers that were hooked up to the internet at the time. Even the CIA feared the worm, and made the decision to shut down their own email servers in order to prevent further expansion of the worm. All together, the estimated cost of all damages was a staggering $15 billion. A huge hit, to say the least.

7 Sircam

When professionals conclude the execution of a virus, there is a state of peace that fills the air. People can rest, assured that there is one virus that has been destroyed and will no longer be a threat to their computers. However, viruses which linger are the ones we should truly be afraid of. It's viruses like Sircam, a terrible worm, which was released in 2001 and continued to infect computers for quite some time. Via the power of social networking, Sircam scammed people, infected their computers and chose a random file from Microsoft Office. The worm then infected the file and sent it out to all of the contacts in the victim's email. The users who receive the email would then open the file, believing it to be from someone familiar. According to a study from a Florida university, an estimated $3 billion in damage came about from the virus, and to this day it is considered one of the worst computer worms in history.

6 Nimda


Terrorism is a huge scare in the United States, as well as any other country around the world. It's only natural to be fearful of the threats that come from terrorists. And many people were scared when the famous worm, Nimda, decided to rear its ugly head. Nimda surfaced in 2001, just after the 9/11 attacks, leading many officials to believe that it had a connection to Al Qaeda. However, it was shortly figured out that the virus had no connection with them whatsoever. And like other viruses on the list which have been known to corrupt information and even hold your information ransom, Nimda caused massive damage. The virus was used to bring down federal courts, banking networks, all with very important computer systems. In just the first few days of the attack, the costs to fix the unnecessary mess pushed past $500 million. The proper actions were taken in order to build security backup and Nimda was finally compromised.

5 Code Red


Certainly, one of the scariest events that could happen to the US would be to have the system completely taken over and run by someone who is entirely corrupt. And while this has yet to happen, something close to it did happen in the year 2001. A virus known as Code Red was released and caused a significant amount of damage. The virus was given its name by its creators based on the Mountain Dew drink Code Red. The virus infected up to one third of Microsoft ISS web servers, and caused chaos among the systems. Even the White House, whose cyber security is considered rather strong, had an incident involving Code Red. The homepage for had been replaced with a strange message, and the dollar amount to fix the damages rose to the billions. To this day, there have been other viruses crafted in the likeness of Code Red, but none have yet to obtain the popularity this one did so long ago.

4 Stuxnet


It's been said that war never changes, and that is true for the world. However, even as we move forward, our armies are always looking for different ways to gain the advantage in war and certain methods are better than others. But one of the most recent methods exists as cyber warfare. Stuxnet, which is a very famous virus, was used in 2009 to try and disrupt a specific area of Iran's defense. Created by both the US and Israel, the virus was to be used to gain an advantage, and was used on the country's nuclear enrichment systems. The virus could infect computers and cause the nuclear centrifuges to spin in a constant motion until the machines broke down. Not only that, but the virus could also provide corrupted feedback, showing that everything was fine with the equipment. It was considered by many to be the world's first digital weapon and it reigns in history as one of the most clever pieces of work from the US and Israel.

3 MyDoom

Hackers are growing more advanced every year. And with that increase in knowledge comes a better need to make sure all cyber activities are protected when trying to access the internet. But truly, how safe are we? In 2004, that advancement towards safety proved to be a little out of reach as what was considered to be the worst computer virus outbreak of the time infected and damaged so many computers and online systems. MyDoom was its name, and it did many different things to cause disruption. Because of the virus, the page load time online was increased by 50%, and most antivirus software was blocked, preventing anyone from accessing a means to get rid of the virus. It also launched a denial of service attack on Microsoft. John Bumgarner, a director of the US Cyber Consequences Unit, was part of a group of people who were suspicious that the cyber attack had come from North Korea, saying: "There's been a lot of chatter recently about cyber war. The North Koreans may have felt they were not getting enough attention launching missiles, so they moved into another potential warfare – cyber. It's a form of sabre rattling. But did the North Koreans launch it themselves, or did someone do it for them?"

2 SQL Slammer/ Sapphire


Sometimes, all it takes for a computer to become infected is a very small file. Not all viruses possess a large data count, and some like the SQL Slammer/Sapphire, are so small that they barely become noticed until they are a giant problem for computer users around the world. In 2003, SQL Slammer/Sapphire became a huge problem after it was released. The worm was only 376 bytes, making it rather small, but that didn't take away from the damage it would cause. The worm ended up slowing down the internet, disabling some of the 911 call centers, taking down 12,000 ATMs of Bank of America, and causing much of South Korea to go offline. Additionally, the virus knocked a power plant in Ohio completely offline. What makes this virus one of the worst in history was its ability to disrupt so much within such a short span of time. Certainly, SQL was one of the worst cyber hits in history.

1 Cryptolocker

The scariest virus to make it on the list is one that taps into our deepest fears. Is there anything scarier than having our personal data held at ransom? Even worse, is there anything that can compare to having the data we need deleted forever? That's what many people were asking themselves in 2014 when the virus Cryptolocker was released, infecting multiple computers around the world. Once the virus was inside your computer, you had a specific amount of time. If $300 was not paid to the hacker, the encryption placed on your computer could not be unlocked, leaving the files you hold dear to be deleted forever. It's something that the FBI stepped into and took very seriously. They halted the process at one point, warning users to take as many precautions as possible. At the time, experts were having a hard time finding a fix to the problem. Even to this day, professionals are having difficulty dealing with hackers.

Sources: TechRepublic, Sans.Org

Give TheRichest a Thumbs up!

More in Most Shocking