What is a Computer Virus?

A computer virus is a type of malicious software program (“malware“) that, when executed, replicates itself by modifying other computer programs and inserting its code. When this replication succeeds, the affected areas are then said to be “infected“. Viruses can spread to other computers and files when the software or documents they are attached to are transferred from one computer to another using a network, a disk, file-sharing methods, or through infected email attachments.

A computer virus is a type of harmful program. When it runs, it makes copies of itself and adds its code to other programs and files on your computer. These viruses come in different types, and each type can affect your device differently. Simply put, a computer virus changes how your computer works and aims to spread to other computers. It does this by attaching itself to normal programs or documents that can run code, known as macros.

A virus can harm or destroy data, slow down system resources, and log keystrokes, among other things. A virus can have unexpected or harmful outcomes during this procedure, such as destroying system software by corrupting data. Some viruses are made to mess things up by deleting files, messing up programs, or even wiping out your hard drive completely. Even if they’re not super harmful, viruses can still slow down your computer a lot, using up memory and making it crash often. Others might just make copies of themselves or send so much stuff over the internet that it’s hard to do anything online.

Viruses and malware are often used interchangeably, but they’re not quite the same. Here’s how they differ:

Aspect	Virus	Malware
Definition	A type of malicious software	A broader category of harmful software
Behavior	Self-replicating	Can include viruses, worms, trojans, etc.
Spread	Often requires user interaction	Can spread through various methods, including email, downloads, and vulnerabilities
Damage	Can corrupt or delete files	Can cause a range of harm, including data theft, system damage, and spying
Detection	Can be detected by antivirus software	Requires comprehensive security measures and practices
Examples	Morris Worm, ILOVEYOU	WannaCry ransomware, Zeus trojan

Viruses have been attacking various devices for a long time, spreading through the Internet or other means. They are often created to steal information or completely ruin devices. The first computer virus, called the “Creeper system,” appeared in 1971 as an experimental virus that could copy itself. Following that, in the mid-1970s, the “Rabbit” virus emerged, which replicated very quickly and caused significant damage at the same pace. The virus known as “Elk Cloner” was created in 1982 by Rich Skrenta. It spread through a floppy disk containing a game and attached itself to the Apple II operating system.

The first virus for MS-DOS, called “Brain,” appeared in 1986. It was designed by two Pakistani brothers and overwrote the boot sector of floppy disks, making it impossible for the computer to start. It was originally meant to be a copy protection system. In 1988, more destructive viruses began to surface. Until then, most viruses were considered pranks with funny names and messages. However, in 1988, “The Morris” became the first widely spreading virus.

Keeping your computer safe from viruses is a lot like keeping yourself from catching a cold. Just as you might wash your hands regularly or avoid sick friends, there are simple steps you can take to protect your computer. Here are some easy tips:

1. Install Antivirus Software: Think of antivirus software as your computer’s doctor. It works around the clock to detect and block viruses before they can infect your system. Make sure to keep it updated!

2. Update Regularly: Keep your operating system, software, and apps up to date. Updates often include fixes for security vulnerabilities that viruses could exploit.

3. Be Cautious with Emails and Downloads: Don’t open emails or download attachments from unknown sources. If an email looks suspicious, even if you know the sender, it’s best to delete it.

4. Use Strong Passwords: Protect your accounts with strong, unique passwords. Consider using a password manager to keep track of them all.

5. Backup Your Data: Regularly back up your data to an external drive or cloud storage. If a virus does slip through, you won’t lose everything.

By following these steps, you can help keep your computer virus-free and running smoothly.

To remove a computer infection, you can choose from two options:

Do-it-yourself manual approach: This means you try to fix the problem on your own. Usually, you start by searching online for solutions. Then, you might have to do a lot of tasks to clean up your computer. It can take time and might need some experience to finish everything.

Get help from a reliable antivirus product: Another option is to use antivirus software. This software is designed to find and remove viruses from your computer. You just need to install it and let it do its job.

Antivirus software is a program that searches for, detects, prevents, and removes software infections that can harm your computer. Antivirus can also detect and remove other dangerous software such as worms, adware, and other dangers. This software is intended to be used as a preventative measure against cyber dangers, keeping them from entering your computer and causing problems. Antivirus is available for free as well. Anti-virus software that is available for free only provides limited virus protection, whereas premium anti-virus software offers more effective security. For example Avast, Kaspersky, etc.

Also Check :

Anti-Virus | Its Benefits and Drawbacks

How an Antivirus Works?

Each type has a unique way of infecting and damaging computers. Here are a few examples:

Type of Virus	Description
Boot Sector Virus	Attacks the part of the computer that starts up when you turn it on. Boot Sector Virus can also spread through devices like floppy disks. Often called a memory virus.
File Virus	Attaches to the end of a file and modifies how a program starts to run the virus’s code first.
Email Virus	Hides in email messages and activates by clicking a link, opening an attachment, or interacting with the email.
Polymorphic Virus	Changes its form every time it installs to avoid detection by antivirus software.
Macro Virus	Activates by running a program capable of executing macros, often found in documents like spreadsheets.
Multipartite Virus	Infects the computer’s boot sector, memory, and files, making it difficult to detect and remove.
Encrypted Virus	Uses encryption to hide from antivirus software, includes a decryption algorithm to run before executing.
Stealth Virus	Modifies detection code, making it very difficult to detect.
Resident Virus	Saves itself in the computer’s memory and can infect other files even after the original program stops.
Direct Action Virus	Tied to an executable file, it activates when the file is opened but does not delete files or affect system speed; blocks file access.
Browser Hijacker Virus	Changes browser settings without permission, can redirect to malicious sites.

Through the following activities you may get your device infected by the virus :

1. Sharing the data like music, files, and images with each other.

2. If you open a spam email or an attachment in an email that is sent by an unknown person.

3. Downloading the free games, toolbars, media players, etc.

4. Visiting a malicious website.

5. Installing pirated software(s) etc.

A computer virus is a type of software designed to spread from one computer to another, similar to how a cold spreads between people. Just like a cold virus can make us sick, a computer virus can harm a computer’s performance and security. Here are some common examples of computer viruses:

Virus Name	Description
Morris Worm	One of the first and most widespread computer viruses, the Morris Worm was a self-replicating program that spread across the early Internet in 1988, causing delays and crashes on many devices.
Nimda	Appearing in 2001, Nimda targeted web servers and computers running Microsoft Windows. It spread through various methods, infecting quickly and widely.
ILOVEYOU	In 2000, the ILOVEYOU worm spread through emails disguised as love confessions. It overwrote data and caused extensive damage.
SQL Slammer	This fast-spreading computer worm emerged in 2003, exploiting a vulnerability in Microsoft SQL Server. It caused significant network congestion and disrupted Internet services.
Stuxnet	Developed in 2010, Stuxnet was a sophisticated worm aimed at damaging industrial control systems, particularly Iran’s nuclear facilities. It exploited zero-day vulnerabilities.
CryptoLocker	CryptoLocker, a ransomware Trojan from 2013, infected hundreds of thousands of computers, encrypted victims’ files, and demanded a ransom to unlock them.
Conficker	First detected in 2008, Conficker exploited weaknesses in Windows operating systems, creating a large botnet and causing widespread infections.
Tinba	Discovered in 2012, Tinba is a banking Trojan that primarily targets financial institutions to steal login credentials and banking information.
Shlayer	Since 2018, Shlayer has been a macOS-specific Trojan spreading adware and unwanted programs through fake software updates and downloads.

These examples show how diverse computer viruses can be in their methods of infection and damage. Knowing about them can help you understand the importance of having reliable antivirus software and practicing safe browsing habits.

In conclusion, understanding what a computer virus is and recognizing the dangers it poses is crucial for keeping your data safe. These viruses are designed to infect, replicate, and damage the functioning of computers. Protecting your computer with antivirus software, being cautious with email attachments, and avoiding suspicious websites are essential steps to prevent virus infections. By staying informed and attentive, you can help safeguard your computer from the potential destruction caused by computer viruses.

How can you protect your computer system from viruses?

We can use antivirus software to keep your computer safe from viruses. Antivirus software works by comparing the files and programs on your computer to a database of known malware types. It will also monitor computers for the presence of new or undiscovered malware threats, as hackers are constantly generating and propagating new viruses.

What are computer virus infection sources.

The sources via which you can infect your system with viruses are :
1. Downloading programs/software from the internet.
2. Emails
3. External devices like pen-drives
4. Using an unknown CD to Boot data
5. Bluetooth/ infrared

How do computer viruses spread?

Computer viruses are typically propagated by email, file sharing, or CDs or by downloading file(s) from unauthenticated sources.

What is an Anti-Virus?

An anti-virus is a piece of software that consists of programs or a collection of programs that can detect and remove all unsafe and malicious software from your system. This anti-virus software is created in such a way that it can look through a computer’s files and detect which files are heavily or moderately infected by a virus.