Top 10 the most dangerous viruses of all time

Top 10 the most dangerous viruses of all time

Computer viruses are really similar to real-life ones. They can infect thousands of PCs in just one hour, so we really can call it an epidemic. Agreed, it is really interesting to look at how each virus works and how antivirus programs have become a necessity for anyone, who has an electronic device. So, we have made a list of top 10 the most dangerous viruses in history.

  • CIH, 1998
    This virus was created by a student from Taiwan, whose initials were CIH. It had spread across the network on 26th April – the date of the Chernobyl accident, so a lot of users call it simply – Chernobyl. This virus is dangerous because it not only overwrites data on the host PC’s hard drive making it unusable, it was also capable of overwriting the BIOS of the host – after this the PC can’t boot-up. For the time being CHI or Chernobyl has infected nearly half a million PC around the world.
  • Morris worm (1998)

    The first ‘Worm’ virus. It gained a huge amount of attention via press and the creator was the first person convicted in the USA under Computer Fraud and Abuse Act. November 1998 was remembered as the month when one virus paralyzed the work of the entire Internet, which resulted in direct and indirect losses totalling $96 million. It crashed a lot of PCs because of a minor mistake in it’s’ code – it continued installing on one PC an unlimited number of times, causing the total death of the system.

  • Melissa (1999)

    On Friday, March 26, 1999, a new problem appeared– Melissa. It’s an email based virus. You received an e-mail, that contained just one sentence, “Here is that document you asked for…don’t show anyone else. ;-),” with an attached Word document. Nowadays we understand that it is a virus, but way back in 1999, it was something new. Those who opened DOC file ( there were thousands who did so) allowed the virus to infect their system and send this email to all the contacts in your email account using your name. Even worse, this virus modified users’ Word documents with quotes from the TV show “The Simpsons. The cybercriminal responsible was caught and sentenced to twenty months’ imprisonment.

  • ILOVEYOU (2000)

    The most romantic one on our list of dangerous viruses is the ILOVEYOU virus. Maybe because of its lovely name or insidious strategy it infected 45 million users for two days! The CHI virus would have taken about two years. So how did it work? A person receives an email with a file called “LOVE-LETTER-FOR-YOU” with a vbs extension (Visual Basics script). When it entered into the system it would replace all your files, images, music and then it spread itself to all of your contacts.. The damage was enormous – no one had expected this type of virus. And do you know what? The creator was found but wasn’t charged for this crime, because the Philippines had no laws against cyber criminals at that time.


  • Code Red (2001)

    July 13, 2001 – The day when another virus infected the Web. This time it didn’t need you to install a malicious file or even open the email. Code Red or Bady virus just needed an Internet connection with which it changed the Web page that you opened by displaying a text “Hacked by Chinese!”. It spread very quickly and it took less than a week to infect almost 400 000 servers, that’s nearly one million damaged computers.


code red site
code red virus
  • MyDoom (2004)

    My Doom appeared in the malware world on 26th January 2004. Not for days, but for hours it infected nearly 2 million PCs! So how did it worked? It came as an attachment to an e-mail with an error message containing the text “Mail Transaction Failed.” When you clicked on the attachment it duplicated this e-mail to all addresses found in your address books. To stop this invasion was really difficult because the virus blocked access to the sites of anti-virus software developers, as well as Microsoft update services.

  • Sasser (2004)

    This virus impressed the world because it managed to shut down the satellite communications for French news agencies and even led to the cancellation of several Delta airline flights. Impressive, isn’t it? Instead of email, this virus used a security flaw in non-updated Windows 2000 and Windows XP systems to break into the system. Once the virus infected a computer, it looked for other vulnerable systems. Infected systems were experiencing repeated crashes and instability. The interesting thing is that this virus was written by a student, who released the virus on his 18th birthday. He was a really lucky one because he wrote the code when he was a minor, so he just got a suspended sentence.


SASSER virus
  • Bagle (2004)

    At the beginning of 2004 new virus appeared – Bagle worm. It has a classic method of infection – via emails. Why have we put it in the list? Because this virus is the first one that was created to make profit by gaining access to financial, personal and other information. Since then a malware-for-profit movement has appeared and is currently the huge problem for a lot of users and antivirus companies.

  • Conficker (2008)

    Worm Win32 Conficker or just Conficker is a very insidious virus, written specifically for the attacking the Microsoft Windows systems. Using OS vulnerabilities, “Conficker” slipped by unnoticed by antivirus programs and even worse – it blocked access to updates from their databases and updates for the OS. The names of all services were substituted, and the virus was registering in different parts of the system, so it was almost impossible to find and destroy all its fragments. There were more than 12 million infected computers in the world and it gave a harsh lesson to antivirus companies and OS providers to improve their security.

  • Stuxnet

    Last, but definitely not least was the worm called Stuxnet. It was discovered in 2010 and you’ve probably already heard about it. It targeted industrial control systems that are used to monitor and control large-scale industrial facilities, including power plants, dams, waste processing systems and chemical and nuclear operations. It allows the hackers to take control of every important system controls without being noticed. This is the first ever attack that allows cybercriminals to manipulate real-world equipment and bring huge damage to world security. Iran has suffered the most damaging effects of Stuxnet (nearly 60 percent of all the damage caused)..


Stuxnet dangerous
Stuxnet virus

So, as we can see it took less than 20 years to develop viruses from the commonplace spam email to a real huge threat to the world. What will be next? Will antivirus programs be capable of protecting us in future? And what about world peace? There are a lot of questions and there are no definite answers. Leave a comment below, what do you think awaits us in the future of viral progression?

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