The Scariest Computer Viruses Ever and The Damage They Caused The Scariest Computer Viruses Ever and The Damage They Caused

Halloween has arrived which means that spooks, ghosts, and goblins are out in full force. With possible Halloween scares all around, we are all on alert for any risks that may come our way. Regardless of the time of year, computer viruses are always a risk and as you may know, some have caused extensive damage.

Years ago, these computer viruses relied on humans to spread the virus to other computer systems. Hackers commonly saved viruses to disks and distributed these disks to other computer users. When modems became common, computer virus transmission became a real problem, real fast. In 2017, when we think of a computer virus, we understand they are usually transmitted via the Internet. Computers can become infected through email messages and/or website links shared by people you know. These programs can often spread much faster than the earlier computer viruses.

Here are some of the scariest computer viruses to have caused damage to computer systems.

    1. CryptoLocker

      Released in September 2013, CryptoLocker spread through email attachments and encrypted files so they could not be accessed by the user. CryptoLocker was a special kind of malware, called ransomware, so the hackers would send a decryption key in exchange for a sum of money. In some cases, a System Restore or recovery software worked but in most cases, if the user didn’t pay the hacker, they would lose all of their files.


    1. Stuxnet

      First identified in 2010, some think Stuxnet was in development since at least 2005. This worm was one of the scariest computer viruses because it targeted industrial computer systems and was responsible for causing substantial damage to Iran’s nuclear program. It is commonly described as a jointly built American-Israeli cyberweapon although neither side has claimed responsibility for it. It specifically targeted programmable logic controllers (PLCs) that allow for the automation of electromechanical processes (assembly lines, amusement rides, etc.).


    1. Storm Worm

      In late 2006, the Storm Worm was first identified. The public started to call the virus the Storm Worm because one of the email messages carrying the virus had “230 dead as storm batters Europe” as its subject line. Others called it Peacomm and Nuwar. This was a Trojan horse program and there were many variations that did a lot of damage but it’s not the most difficult to detect or remove from a computer system.


    1. Leap-A/Oompa-A

      In 2006, the Leap-A virus debuted. It used the iChat® instant messaging program to spread across vulnerable Mac® computers. After it infected the computer, it searched through iChat contacts and sent messages to each person on the list. The message contained a corrupted file although it appeared to just be a JPEG image. It didn’t cause much harm but it showed that even Mac computers are vulnerable.


    1. The Sasser

      In the spring of 2004, Microsoft released a patch for a vulnerability in Windows’ Local Security Authority Subsystem Service (LSASS). Shortly after the release, a teenager in Germany created the Sasser worm to exploit the vulnerability in unpatched machines. The worm ended up taking out airlines, public transit, and hospital networks, causing nearly $18 million in damage.


    1. MyDoom

      My Doom (or Norvag) also created a backdoor in the computer’s operating system. This was one of the worst computer viruses because there have been several variations of the original MyDoom virus. The original, however, had two triggers. One caused a denial of service (DoS) attack on February 1, 2004. The second commanded the virus to stop distributing itself on February 12, 2004. The backdoors remained active even after February 12th and a second outbreak later in 2004 gave a few search engine companies trouble. It spread through email and peer-to-peer networks. At one point, it is said one in every twelve email messages carried the virus.


    1. SQL Slammer/Sapphire

      The SQL Slammer virus (aka Sapphire), a web server virus, reared its ugly head in January 2003. Computer networks were unprepared for the attack and it brought down several important systems such Bank of America’s ATM service, the city of Seattle suffered outages in 911 service and Continental Airlines was forced to cancel several flights as a result of electronic ticketing and check-in errors. More than $1 billion in damages was caused before patches and antivirus software could catch up.


    1. Nimda

      Nimda, or “admin” spelled backwards, hit the Internet in 2001. It became the fastest propagating computer virus at that time. Some say it only took 22 minutes from the moment it hit the Internet to reach the top of the list of reported attacks. The Nimda worm developed a backdoor into the computer’s operating system allowing the person responsible for the attack to access the same level of functionality as the account that was currently logged into the computer would have had. It caused some network systems to crash entirely.


    1. Code Red and Code Red II

      Both of these worms appeared in summer 2001, exploiting an operating system vulnerability that was found on computers running Windows 2000® and Windows NT®. It was able to overwrite adjacent memory. The original Code Red was responsible for a distributed denial of service (DDoS) attack on the White House. The effect of the computer virus depended in large part, on the operating system that computer was running. Microsoft® did release software patches that addressed the vulnerability in Windows 2000® and Windows NT®.



    Initially, the ILOVEYOU virus got around by email with the subject line stating that it was a love letter from a secret admirer. The email came with an attachment that caused all the problems. When opened, the virus copied itself several times and hid these copies in several folders on the computer’s hard drive. It replaced different kinds of files with copies of itself and added new files to registry keys. It had the ability to send itself through Internet Relay Chat clients and email. And worst of all, it downloaded and executed a file that was a password-stealing application that would send secret information to the hacker’s email address.

This Halloween while you are planning your costumes to protect yourself from all the ghouls wandering around your community, make sure you protect your computer as well. There are many scary computer viruses out there and more being created every day that can cause incredible damage to your computer and personal life. It’s important to keep your antivirus software up to date as well as steering clear from anything that arises suspicion and could be one of the scariest computer viruses.

Call Geeks on Site today to discuss updating your antivirus software on all of your laptops and computers.

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