Top Most famous, Dangerous, Deadliest viruses ever made in world history!! : computer virus protection easy ways

What is a virus?

A computer virus is a type of computer program, much like a flu virus. Computer Virus is designed to replicate itself by modifying other computer programs. It has the ability to spread itself from host to host.

Similarly, in the same way, that flu viruses cannot reproduce without a host cell, computer viruses cannot reproduce and spread without programmings such as a file or document or we can say host program.

whereas  A computer worm does not need a host program, as it is an independent program or code chunk.  So it can run independently and actively carry out attacks.

Inexact technical terms, A computer virus is a type of malicious code or program written to alter the way a computer operates. It is designed to spread from one computer to another. A virus operates by inserting or attaching itself to a legitimate program or document that supports macros to execute its code. In the process, a virus has the potential to cause unexpected or damaging effects, such as harming the system software by corrupting or destroying data.

The list of  most famous, Dangerous, Deadliest, harmful viruses is :::::


Melissa was created by programer David L. Smith in the year 1999. It started as an infected Word document that was posted up on the USENET group. The document claimed that it consisted list of the password of different porn sites. Which easily got the attention of the many victims and people who opened it got hacked. Also, some of the emails would consist of Simpsons reference as that is a popular animated series and had a lot of fan following.

The virus will mail itself to the top 50 people in the user’s email address book and this caused an increase in email traffic, disrupting the email services of governments and corporations.  It has been amused that almost a million emails had been affected by this virus.

It also sometimes corrupted documents by inserting a Simpsons reference into them.

Smith was eventually caught when they traced the Word document to him. The file was uploaded using a stolen AOL account and with their help, law enforcement was able to arrest him less than a week since the outbreak began.

It is estimated that around 80 million dollars were used for the clean-up and to solve the damage that was done due to this virus.

He cooperated with the FBI in capturing other virus creators, famous among them the creator of the Anna Kournikova virus. For his cooperation, he served only 20 months and paid a fine of $5000 of his 10-year sentence.


The computer virus Nimda first appeared on September 18, 2001, Nimba was spread through the Internet rapidly. In fact, This harmful virus took only  22 minutes from the moment Nimda hit the Internet to reach the top of the list of most reported attacks.

The Cooperative Association of Internet Data Analysis said that the Nimda virus contaminated nearly more than 160,000 systems.

The main purpose of the Nimda computer virus was to bring Internet traffic to a crawl. this virus was able to create a backdoor in the victim’s operating system, that would give full access to the attacker to the same level of functions. And also, if the victim was the administrator for the machine, the attacker would have full control.

The virus code includes the text: Concept Virus(CV) V.5, Copyright(C)2001 R.P.China

Nimda worm became a distributed denial of service (DDOS) attack afterward. The spread of the Nimda virus caused a larger no of network crashes as more of the system’s resources became fodder for the worm.


The Code Red computer virus was created by two eEye Digital Security employees Marc Maiffret and Ryan Permeh.  Actually, they were drinking Code Red Mountain Dew that time. So they named it “Code Red”.

The virus came online on the internet in 2001 .code red specifically targeted the computers with Microsoft IIS web server installed by exploiting a buffer overflow problem in the systems. when the computer got infected, it will proceed to make a hundred copies of itself repeatedly due to a bug in the programming. It will duplicate even more and more at last led to ends up eating a lot of the system’s resources.

It will then launch a denial of service attack on several IP addresses, It also allows backdoor access to the server, allowing for remote access to the machine.

The most famous attack among all of the attacks was on the White House website. Also, the Pentagon shut down their hundreds of Defense Department Web pages so that they can  install protection against “Code Red virus.”

the Code Red computer virus was yet another worm that penetrated 975,000 hosts it was estimated that it caused $2 billion in lost productivity. It displayed the words “Hacked by Chinese!” across infected web pages,


ILOVEYOU is considered one of the most virulent computer viruses ever created.

ILOVEYOU  virus originated in the Philippines, The virus was created by two Filipino programmers, Reonel Ramones and Onel de Guzman.  This virus started spreading and infecting computers on May 5, 2000.

The virus spreads by email with the subject line “ILOVEYOU” and an attachment, “LOVE-LETTER-FOR-YOU.txt.vbs”. It managed to start destruction on computer systems all over the world with around $10 billion worth of damages. i.e Approx 10% of the world’s computers have been infected by this virus.

It was so bad that governments and large corporations took their mailing system offline to prevent infection.

This computer used social engineering to get people to click on the attachment, In that attachment, there was a love confession. The attachment was actually a script that poses as a TXT file, due to Windows at the time hiding the actual extension of the file.

If the attachment was opened, a Visual Basic script was executed, the virus will send itself to everyone in the user’s mailing list and proceed to overwrite files with itself, making the computer unbootable.


The WannaCry computer virus came in the year 2017,  it was a ransomware virus.
A wanna cry virus that takes control over your computer (or cloud files) and holds them hostage. The WannaCry ransomware split through computers in 150 countries including( USA, UK, INDIA, CHINA, GERMANY, etc.)
This caused massive productivity losses in businesses, hospitals, and government organizations. The total productivity loss was calculated as approx $4 billion. The companies that didn’t pay were forced to rebuild systems from scratch.
The malware raged like wildfire through 200,000 computers worldwide. It stopped when a 22-year-old security researcher in the U.K. found a way to turn it off. Computers with out-of-date operating systems were hit especially hard.

Zeus Gameover

Zeus virus was First identified in 2009. This computer virus is a part of the “Zeus” family of malware and viruses. This virus was a form of malicious software that targets Microsoft Windows. Spam messages and drive-by downloads are two main methods of infection.
The Zeus virus managed to compromise thousands of FTP accounts and computers from large multinational corporations and banks such as Amazon, Oracle, Bank of America, Cisco, etc. It had breached 88% of all Fortune 500 companies, 2,500 organizations total, and 76,000 computers in 196 countries.

Controllers of the Zeus botnet used it to steal the login credentials of the social networks, email. Also, The second main purpose of the Zeus virus is to access the victim’s sensitive bank account details and steal all of the victim’s funds.

The virus can bypass centralized servers and create independent servers to send sensitive information and a victim cannot even trace his/her stolen data. Also in some cases, Zeus can download ransomware that encrypts your files and make them hostage, and demand money in exchange for unlocking them.

Zeus caused documented damage of $100 million. But the real cost in terms of lost productivity, removal, and undocumented theft is undoubtedly much higher i.e Approx $3 billion.


Conficker computer virus first appeared in 2008.  The virus has two more popular names Downup or Downadup, Conficker infects computers using flaws in the OS to create a botnet. The malware was able to infect more than 9 million computers all around the world,  Conficker affected governments, businesses, and individuals. It was one of the largest known worm infections to ever surface causing estimated damage of $9 billion.

The worm works by exploiting a network service vulnerability that was present and unpatched in Windows. Once your device is infected by the Conficker virus, the worm will then reset account and lockout policies, block access to Windows update and antivirus sites, then it will turn off certain services and lockout users from its accounts.

Then, it proceeds to install software that will turn the computer into a botnet slave and scareware to scam money off the user. Microsoft later provided a fix and patch with many antivirus vendors providing updates to their definitions.


CryptoLocker Ransomware was released in September 2013. This virus was spread through email attachments and encrypted the user’s files. cryptolocker virus is a dangerous form of ransomware that encrypts files on the computer. A Victim has to pay a certain amount through bitcoin in exchange for being able to access the file or documents. To decrypt the file, a person/victim should have a private key to decrypt the file. Once the
files are infected, the files are effectively lost forever.
In June 2014, Operation Tovar took down Evgeniy Bogachev, the leader of the gang of hackers behind CryptoLocker. In February, the FBI offered a cool $3 million reward for Bogachev.

There are many ways to avoid the CryptoLocker virus such as by updating antivirus software and malware protection, ignoring suspicious attachments or files, and not clicking on random or unrecognized links.  Also, it is always a great idea to always back your files up.


MyDoom, the first version of the worm, appeared on January 26, 2004. This virus originated from Russia and is written in C++ programming language. It spread via email and through a peer-to-peer network.  The virus creates a backdoor in the victim’s computer’s operating system. MyDoom was an odd one, as it hit tech companies like SCO, Microsoft, and Google with a Distributed Denial of Service attack. In 2004, roughly somewhere between 16-25% of all emails had been infected by MyDoom.On Feb 1, 2004, it caused the virus to begin a denial of service (DoS) attack and on Feb 12, it stopped distributing itself. Even after the virus spread, the backdoors created during the initial infections remained active. MyDoom, like ILOVEYOU, is a record-holder and was the fastest-spreading email-based worm ever.

Mydoom is still around today, generating 1% of all phishing emails. That’s no small achievement considering the 3.4 billion phishing emails sent each day. By that figure, Mydoom has taken on a life of its own, infecting enough poorly-protected machines to send 1.2 billion copies of itself per year, 16 years after its creation.
Though a $250,000 reward was offered, the developer of this dangerous computer worm was never caught.

Some easy ways to avoid viruses

  • Regularly Backup your computer
  • Avoid questionable websites
  •  Install up to date antivirus software
  • Avoid pirated software(windows)
  • Be careful with email attachments
  • Regularly check your device.


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