10 of the world’s most dangerous computer viruses

In computing, a computer virus is a type of malicious code or program written to alter the way a computer operates, without the user’s knowledge or permission. In the 1980s, the first computer viruses were created as practical jokes or pranks, but soon after, more malicious viruses were created with the intent to do harm—or simply to cause havoc.

Over the years, there have been many noteworthy and destructive computer viruses, and below are 10 of the most dangerous.

1. ILOVEYOU

Otherwise known as the Love Bug or the Love Letter virus, ILOVEYOU was a computer worm that spread through email attachments in 2000. Created by Filipino programmer Onel de Guzman, ILOVEYOU affected an estimated 10% of all internet-connected computers, causing an estimated $5.5 billion in damage.

2. Code Red

Named after the beverage, Code Red was a computer worm that exploited a flaw in Microsoft’s IIS web server software. It first appeared in July 2001 and within a matter of days, infected over 300,000 computers.

While the worm itself did not do any direct damage, it provided attackers with a means to remotely execute code on an infected machine. This allowed the execution of commands that could, for example, delete files, add users, or shutdown the server.

3. Nimda

Nimda (“admin” spelled backwards) was a computer worm that emerged just a month after the Code Red worm. It used multiple attack vectors to spread itself, making it one of the fastest-spreading worms of all time.

Nimda was particularly notable for its damage, causing an estimated $618 million in damages. It also led to the temporary shutdown of the U.S. Senate’s email system.

4. Sasser

Sasser was a computer worm that spread through a flaw in the Windows LSASS (Local Security Authority Subsystem Service) software. First appearing in 2004, it caused infected computers to crash and then restart continuously.

While Sasser didn’t do any direct damage, the worm quickly spread to thousands of computers, causing significant disruption. It also resulted in a number of high-profile infections, including those at Boeing, Deutsche Post, and FedEx.

5. Mydoom

Mydoom, also known as Novarg, was a computer worm that first appeared in January 2004. It used email attachments and peer-to-peer file sharing networks to spread itself, quickly becoming the fastest-spreading email worm of all time.

Mydoom caused significant disruption, with estimates of the damage ranging from $17 billion to $38.5 billion. It also led to the temporary shutdown of SCO’s website, after the worm was used to launch a distributed denial-of-service attack.

6. Conficker

Conficker, also known as Downup, Downadup, and Kido, was a computer worm that spread through a flaw in the Windows Server service. It first appeared in November 2008 and quickly spread to millions of computers, becoming one of the largest botnets of all time.

While Conficker didn’t do any direct damage, it did provide attackers with a means to remotely control infected computers. This allowed them to steal information, send spam, and launch denial-of-service attacks.

7. Stuxnet

Stuxnet was a computer worm that was specifically designed to target industrial control systems. First appearing in 2009, it was believed to be the first piece of malware that was able to control physical systems.

While the full extent of the damage caused by Stuxnet is not known, it is believed to have caused significant damage to Iran’s nuclear program. It is also thought to have been responsible for the destruction of centrifuges at the Natanz nuclear facility.

8. Flame

Flame, also known as Flamer, sKyWIper, and Skywiper, was a computer virus that was discovered in 2012. It was notable for its size, complexity, and the level of sophistication.

Flame was believed to be used for targeted attacks, with a specific focus on the Middle East. It is thought to have been used to collect information, such as screenshots, keyboard data, and audio recordings.

9. CryptoLocker

CryptoLocker was a type of ransomware that emerged in 2013. It used encryption to lock users’ files, demanding a ransom be paid in order to decrypt them.

While CryptoLocker didn’t cause any direct damage, it did result in a number of high-profile infections, with victims including the City of Torrance, California and the Massachusetts Bay Transit Authority.

10. WannaCry

WannaCry, also known as WannaCrypt, WanaCrypt0r, WCry, and Wanna Decryptor, was a ransomware worm that emerged in May 2017. It quickly spread to over 150 countries, resulting in some of the largest ransomware attacks in history.

WannaCry infected victims’ computers by exploiting a flaw in the Windows SMB (Server Message Block) protocol. It then demanded a ransom be paid in order to decrypt the files that it had encrypted.

While WannaCry didn’t do any direct damage, it did result in a number of high-profile infections, including those at the NHS, FedEx, and Telefonica..Click for source

What is a computer virus?

A computer virus is a code or program that is designed to replicated itself and corrupt a computer system. This can happen without the user being aware as the virus can be spread through email attachments or downloads from the internet. A virus will often cause chaos and damage by deleting files, interfering with normal operations or causing pop-up windows with false information. In some cases, a virus can even be used to gather personal information from a user without their knowledge.

Most viruses are created with the intent to do harm, however, there are some that are created for more humorous purposes. No matter the intent, a virus can be difficult to remove and can cause a great deal of damage to a computer system. It is important to have virus protection installed on your computer and to be aware of the signs that a virus might be present.

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