What is a computer virus and how do you protect your computer from viruses?

binary, one, cyborg, cyber security, computer virus, Which type of malicious software program spread throughout the computer files without knowledge of a user?

In the vast digital ecosystem where data flows freely, the computer virus stands as a formidable adversary. This type of malicious software program stealthily infiltrates computer files, often spreading and replicating without the user’s knowledge or consent.

Like a biological virus that invades living cells, a computer virus can corrupt data and hijack system resources. Consequently disrupting the delicate balance of our digital operations. It’s a silent digital predator. It’s capable of causing catastrophic damage before even the most vigilant users are aware of its presence.

Understanding the nature of computer viruses and the strategies for their prevention is not just prudent—it’s imperative for safeguarding the sanctity of our digital domains.

In this article, we explore the anatomy of computer viruses. Additionally, we’ll also unravel their modus operandi, and equip you with the knowledge to protect your computer from viruses.

What is a Computer Virus?

Anybody who owns a computer has ever heard of computer virus. But, what is a computer virus?

A computer virus is a type of malicious software program designed to replicate itself by modifying other computer programs and inserting its own code. When this replication succeeds, the affected areas are then said to be “infected” with a computer virus.

Virus writers use social engineering deceptions and exploit detailed knowledge of security vulnerabilities to initially infect systems and to spread the virus.

The vast majority of viruses target systems running Microsoft Windows, employing a variety of mechanisms to infect new hosts. And often, they harm the compromised computer systems by corrupting or deleting data, stealing personal information, or hijacking system resources.

Ultimately, computer viruses can cause significant harm, ranging from individual user trouble to large-scale economic damages.

The prevention of such malware involves a combination of antivirus software, firewalls, careful internet browsing, and operating system updates.

The Birth and Evolution of Computer Viruses

The Genesis of Cyber Virulence: 1970s- 1980s

The concept of a self-replicating program was first theorized by John von Neumann in the 1940s, but it wasn’t until the 1970s that the first known computer virus, Creeper, emerged. It was benign and simply displayed the message, “I’m the creeper, catch me if you can!” The 1980s saw the advent of personal computers and with it, the first real virus threats.

As we transitioned into the 1980s, the landscape of computing underwent a seismic shift with the introduction of personal computers. This new frontier of technology brought with it the first genuine threats to computer security.

However, it was the advent of personal computing that gave rise to the widespread proliferation of viruses. One of the earliest examples was the Brain virus in 1986. The Brain Virus targeted IBM PC platforms and was spread via floppy disks.

Brain Computer Virus
Brain Computer Virus
Creeper virus
Creeper Virus

This period also witnessed the creation of several other notable viruses. The Vienna virus, appearing in 1987, was one of the first file infectors, targeting .COM files.

That same year, the Cascade virus emerged. The Cascade virus had the ability to encrypt its code to evade detection—a harbinger of the sophisticated obfuscation techniques that would become a staple in malware development.

The Explosion of Viruses: 1990s

The 1990s witnessed an explosion of computer viruses. This could be attributed to the growing popularity of Windows operating systems and the rise of the internet.

One of the most infamous viruses of this time was the Michelangelo virus, discovered in 1991. It was a boot sector virus that lay dormant until March 6th—the birthday of the renowned artist Michelangelo—upon which it would activate and overwrite the master boot record, rendering the computer inoperable.

Its discovery led to a media frenzy, with dire warnings of a potential digital apocalypse. Despite the panic, the actual impact was less catastrophic than anticipated.

Another notorious virus that emerged in the late 1990s was the Melissa virus. Created by David L. Smith in 1999. The virus spread via email by tempting users with an attachment that claimed to contain passwords for adult websites.

Once opened, the virus would replicate itself by sending out emails to the first 50 contacts in the user’s address book, leading to significant disruption of email systems worldwide.

Other notable viruses in 1990s

The 1990s saw the emergence of several other notable computer viruses, each contributing to the era’s digital upheaval. Here are a few:

Concept Virus: The first macro virus, appearing in 1995. It targeted Microsoft Word documents and demonstrated the potential for viruses to spread through software applications.

CIH (Chernobyl): Emerging in 1998, this virus was notorious for its destructive payload, which could overwrite system information and render PCs unbootable.

Form Virus: Identified in Switzerland, the Form virus was prevalent in the 1990s, often found in the wild due to its ability to infect the boot sector of floppy disks.

Polymorphic Viruses: The 1990s also saw the rise of polymorphic viruses. These viruses could mutate their code to evade detection by antivirus software.

These viruses underscored the evolving complexity of malware and the increasing need for advanced cybersecurity measures.

They also highlighted the importance of developing robust antivirus software and the need for users to exercise caution when opening email attachments.

The 1990s were not just a decade of technological advancement but also a period that shaped our understanding of digital security and the ongoing battle against cyber threats.

The Era of Email Worms: Early 2000s

As the new millennium dawned, the digital world faced a burgeoning threat that would redefine the landscape of cyber security: the email worm.

At the forefront of this digital onslaught was the ILOVEYOU virus, also known as Love Bug. Launched in May 2000, it masqueraded as a love letter from a secret admirer, with an attachment that, once opened, unleashed a malicious script. It overwrote files, plundered user contacts, and self-propagated to everyone in the victim’s address book.

The simplicity of its social engineering belied its destructive potential; it caused an estimated $10 billion in damages and affected millions of computers worldwide.

I love you computer virus
“ILOVEYOU” Computer Virus

Hot on its heels came the Sobig worm, a multi-staged threat that debuted in 2003. It became one of the fastest-spreading worms of its time, using email to distribute itself and a network of infected computers to relay spam. Its most notorious variant, Sobig.F, at its peak, accounted for a staggering one in every seventeen emails sent.

Not to be outdone, the Mydoom worm emerged in 2004, setting a new record for infection rates. It spread by sending out emails with random senders’ addresses and subject lines, enticing recipients to open an attachment that would trigger the worm. Mydoom caused widespread disruption, particularly targeting search engines with a denial-of-service (DoS) attack, and its impact was felt long after its initial release.

These email worms of the early 2000s served as a stark reminder of the vulnerabilities inherent in our interconnected systems. They underscored the need for robust email security protocols, the importance of user education on the dangers of unsolicited attachments, and the ever-present need for vigilance in the digital age.

Advanced Persistent Threats: Mid-2000s to 2010s

In the mid-2000s to 2010s, the cyber threat landscape underwent a dramatic transformation with the emergence of Advanced Persistent Threats (APTs). These sophisticated attacks marked a significant shift from the opportunistic viruses of the past to highly targeted, stealthy, and persistent cyber-espionage campaigns.

Stuxnet: The Cyber Weapon That Shook the World Stuxnet, discovered in 2010, was a game-changer. It was a highly complex worm designed to sabotage Iran’s nuclear program by causing the centrifuges at the Natanz facility to spin out of control. Stuxnet’s intricacy was unprecedented; it utilized four zero-day exploits and had the ability to reprogram industrial control systems. This level of sophistication indicated the involvement of state-sponsored actors, and it opened a new chapter in cyber warfare.

CryptoLocker: The Extortionist’s Tool Following Stuxnet, the world saw the rise of ransomware, with CryptoLocker being one of the most infamous examples. Emerging in 2013, CryptoLocker encrypted users’ files and demanded a ransom, typically in Bitcoin, for the decryption key. Its success spawned a multitude of copycats, leading to a ransomware epidemic that continues to evolve and plague individuals and organizations alike.

Polymorphic and Metamorphic Malware During this period, polymorphic and metamorphic malware also became prevalent. These viruses could alter their code with each infection, making them incredibly difficult to detect and remove. They represented a significant challenge for traditional antivirus software, which struggled to keep pace with the rapidly changing threat landscape.

APT28 and APT29: Espionage at Its Peak The latter part of the decade saw the rise of APT groups like APT28 (Fancy Bear) and APT29 (Cozy Bear), which were linked to Russian intelligence services. These groups were implicated in numerous high-profile cyber-espionage activities, including the 2016 US election interference.

The Modern Landscape: 2020s

As we venture deeper into the 2020s, the cyber threat landscape has become more intricate and perilous than ever before. The decade has been marked by an escalation in state-sponsored cyber warfare, where nations use cyber tactics to gain strategic advantages over adversaries. These operations often involve sophisticated espionage tools that can disrupt critical infrastructure and steal sensitive government data.

Zero-day exploits, vulnerabilities unknown to software vendors, have become a prized tool for hackers. They allow attackers to infiltrate systems before developers have a chance to issue a fix, making them particularly dangerous. The rise of the cybercrime industry has commercialized these exploits, with underground markets selling them to the highest bidder.

Viruses, once simple self-replicating programs, have evolved into complex malware with capabilities far beyond their predecessors. They can now orchestrate massive data breaches, exfiltrating terabytes of confidential data from corporations and individuals alike. Financial theft has also become more sophisticated, with malware like banking Trojans and crypto-mining scripts siphoning funds covertly.

The proliferation of Internet of Things (IoT) devices has expanded the attack surface, providing new vectors for infection. Meanwhile, ransomware has continued to plague organizations, with attacks like Maze and Ryuk showing that no sector is immune.

Recent computer virus outbreaks

  • Clop Ransomware: An advanced variant of CryptoMix ransomware, Clop targets Windows users, disabling Windows processes and applications, including security software, to encrypt files and demand ransom.
  • Fake Windows Updates (Cyborg Ransomware): Hackers have been distributing emails with fake Windows update instructions that actually contain the Cyborg ransomware, which encrypts files and demands a ransom.
  • Zeus Gameover: Part of the Zeus family of malware, this Trojan accesses bank account details and steals funds without needing a centralized server, making it particularly dangerous.

In response to these evolving threats, cybersecurity has had to adapt rapidly. Artificial intelligence and machine learning are being deployed to predict and counteract attacks before they happen. Cybersecurity awareness and education have become paramount, as human error remains one of the most significant vulnerabilities.

As we look towards the future, it’s clear that the battle against cyber threats will continue to be a defining challenge of our time.

Staying informed, vigilant, and proactive is not just a recommendation—it’s a necessity for survival in the modern digital landscape. The 2020s will undoubtedly be remembered as a decade of cyber resilience and innovation.

How Viruses Operate

Viruses operate by attaching themselves to executable files or documents. When the infected file is opened, the virus is executed, typically performing two functions: replication and payload delivery.

The replication process allows the virus to spread, while the payload may perform a variety of malicious actions, from displaying messages to destroying data.

What are some common signs of a computer virus?

Recognizing the signs of a computer virus is crucial for maintaining the health and security of your device. Here are some common indicators that your computer might be infected:

  • Frequent Pop-ups: Unexpected or unusual pop-up windows that appear frequently can be a sign of adware, a type of virus that displays unwanted advertisements.
  • Slow Performance: If your computer suddenly becomes sluggish or programs take longer to open, it could be due to a virus consuming system resources.
  • Crashes and Error Messages: Frequent system crashes or mysterious error messages might indicate that a virus is interfering with your computer’s operations.
  • Unusual Activity: This includes changes in your homepage or passwords, new toolbars you didn’t install, or unexpected software installations.
  • Security Software Disabled: Viruses often try to disable your antivirus software to avoid detection, so if you notice your security program is turned off, it’s a red flag.
  • Emails Sent Without Your Knowledge: If friends report receiving strange emails from you that you did not send, it could be a virus spreading itself via your email contacts.

If you notice any of these symptoms, it’s important to run a full system scan with updated antivirus software and take appropriate action to remove any detected malware.

Regularly updating your software and practicing safe browsing habits can also help prevent infections.

How can you protect your computer from viruses?

The battle against computer viruses is ongoing. Antivirus software, firewalls, and regular system updates are essential tools in the fight to protect our digital lives.

Public awareness and education on safe computing practices also play a vital role in preventing the spread of viruses.

Protecting your computer from viruses is essential to ensure the safety and integrity of your data. Here are some key steps you can take to safeguard your system:

Install Antivirus Software: Choose a reputable antivirus program and keep it updated. Regular scans can detect and remove malicious software.

Avast antivirus, what avast antivirus offers, protect against computer virus
Avast antivirus protection against computer virus and other malware

Keep Your Software Updated: Software updates often include security patches. Keeping your operating system and applications up-to-date can close vulnerabilities that viruses exploit.

Use Strong Passwords: Create complex passwords and change them regularly. Avoid using the same password across multiple sites.

Be Cautious with Email Attachments: Don’t open email attachments from unknown senders, and be wary of unexpected attachments from known contacts.

Enable a Firewall: Firewalls can prevent unauthorized access to your system and alert you to suspicious activity.

Backup Your Data: Regularly backup important files to an external drive or cloud service. This can help you recover your data if a virus causes damage.

Practice Safe Browsing: Avoid clicking on suspicious links or downloading software from untrusted websites. Use ad blockers to prevent malicious ads.

By following these practices, you can significantly reduce the risk of virus infections and keep your computer secure. Remember, the best defense is a proactive approach to cybersecurity.

How can you remove a virus from your computer ?

Removing a virus from your computer involves several steps to ensure that the system is thoroughly cleaned and the malware is completely eradicated. Here’s a general guide to help you remove a virus:

  1. Disconnect from the Internet: Prevent the virus from spreading or leaking your data by disconnecting from the internet.
  2. Enter Safe Mode: Reboot your computer in Safe Mode to prevent the virus from activating. You can usually enter Safe Mode by pressing F8 while your computer starts up.
  3. Check Your Downloads and Temporary Files: Look for any suspicious files you’ve downloaded recently or temporary files that could harbor the virus.
  4. Run a Virus Scan: Use your antivirus software to perform a full system scan. It will identify and isolate any malicious files.
  5. Delete or Quarantine the Virus: Follow your antivirus software’s recommendations to delete or quarantine the infected files.
  6. Update Your Antivirus Software: Ensure your antivirus is up-to-date with the latest virus definitions.
  7. Clear Your Cache and Browser History: Some viruses can live in your browser cache, so clear it out along with your browsing history.
  8. Change Your Passwords: After removing the virus, change your passwords to ensure your accounts are secure.
  9. Update Your Operating System and Software: Install any available updates for your operating system and other software to patch vulnerabilities.
  10. Monitor Your Computer’s Performance: After the cleanup, keep an eye on your computer’s performance for any signs of lingering issues.

If the virus persists or you’re not comfortable performing these steps, consider seeking professional help. Remember, regular backups and preventive measures are key to minimizing the impact of a virus infection.

What is the difference between viruses and other types of malware?

The term “malware” is an umbrella term that encompasses various types of malicious software, each with unique characteristics and modes of operation. Here’s a breakdown of the differences between viruses and other common types of malware:


These are malicious programs that attach themselves to clean files and spread throughout a computer system, infecting files with malicious code. They can disrupt functionality, corrupt files, and spread across networks.


Similar to viruses, worms can replicate themselves, but they do not require a host file to spread. They exploit vulnerabilities in a system or network to spread, often causing widespread damage.


These are deceptive programs that appear legitimate but carry a hidden malicious function. Unlike viruses and worms, they do not replicate themselves but can open backdoors for other malware to enter.

Read more about trojans HERE.

Trojan, computer virus, avast antivirus
Trojan malware


This type of malware encrypts a user’s files and demands payment for the decryption key. It does not spread across systems like viruses but can cause significant data loss and financial damage.


As the name suggests, spyware is designed to spy on user activity, collect personal information, and transmit it to third parties without consent.


Often bundled with free software, adware displays unwanted advertisements and can track browsing habits. While not always malicious, it can be intrusive and affect system performance.

Each type of malware has its own method of infection and damage, making it important to have comprehensive security measures in place to protect against the wide range of threats. Regular updates, cautious online behavior, and robust antivirus solutions are key to safeguarding your digital environment.


In the culmination of our discourse on computer virus, it is imperative to recognize the gravity of these digital threats. The insidious nature of computer viruses, which proliferate through computer files unbeknownst to users, necessitates a vigilant and informed approach to cybersecurity.

To fortify one’s digital sanctum against such clandestine adversaries, one must employ a multifaceted strategy. This includes:

  • installation of reputable antivirus software,
  • diligent updating of software to mend any security fissures that could be exploited by nefarious entities
  • exercising prudence with email attachments and downloads from unverified sources.
  • cyber security education

By adhering to these practices, we not only defend our individual systems but also contribute to the collective security of the digital ecosystem at large.


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