Computer Virus: What Is It, Types and Examples

Definition of computer virus

A computer virus is a malicious program that copies itself into other programs to reproduce. Computer viruses can also infect other executable codes or documents, causing them to reproduce. Computer viruses are designed to infect vulnerable systems and gain administrative power. They also aim to steal user data. Hackers can create a variety of computer viruses and Trojans with malicious intent, and then use deception to prey upon internet users.

There are many ways viruses can spread to your computer. These include opening attachments in emails, visiting infected websites, clicking on executable files, and watching infected advertisements. On the other hand, infections can be spread to your device through email attachments.

Users can spread infections by linking to infected removable storage devices such as USB drives.

Malware can easily infiltrate computers by bypassing security measures. A successful breach can also infect other resources and system software, alter or uninstall key functions, and copy, delete or encrypt data among other things.

Robert Thomas, an engineer from BBN Technologies, created the first computer virus in 1971. The “Creeper” virus was named after Thomas, an engineer at BBN Technologies. Thomas’s experimental software infected ARPANET mainframes. “I’m the creeper. Catch me if possible,” reads the teletype message.

After a year of research, Fred Cohen invented the term “computer virus” in 1983. He coined the term “computer virus” after attempting to write an academic paper titled, “Computer Viruses – Theory and Experiments”, which detailed the malicious programs he had encountered in his research.

Different types of computer virus

A computer virus is a type of malware that embeds its virus code in programs and applications to multiply. Malicious code is used to infect the computer. Software viruses can come in many sizes and infect your system in different ways. These are some of the most well-known computer viruses.

• Virus in the Boot Sector
• Direct Action against Virus
• Multipartite Resident Virus
• Virus with Polymorphic forms
• Virus Spacefiller

Boot Sector Virus

This virus infects your master boot record. It is difficult to remove and can often require that the computer be formatted. It spreads mainly via removable media.

Also read: Top 10 Malware Removal Tools

Direct Action Virus

Also known as a “non-resident virus”, this virus can install itself on the computer or hide in its memory. It attaches to the same file types that it infects. It does not affect the performance of the system or user experience.

Resident viruses

These viruses are not like direct action viruses. They stay on the computer even after they have been mounted. It can be difficult to identify the virus and even more difficult to eliminate a resident virus.

Multipartite virus

This virus is capable of spreading in many ways. It infects both the boot sector as well as executable files simultaneously.

Polymorphic virus

Conventional antivirus systems are unable to identify these viruses. Because polymorphic viruses multiply, the signature pattern of these viruses changes.

Overwrite virus

This type of virus deletes all files on a computer it infects. It is possible to remove the infected files. This will cause the user to lose all files. Because it spreads via email, the overwrite virus can be difficult to identify.

Spacefiller Virus

Also known as “Cavity Viruses”, they fill in the empty spaces between text lines to prevent the file from being damaged.

2. Ways to Prevent Computer Viruses and Various Types of Security Threats

• Runbox is a professional email service. Subscription-based services offer greater security and support.
• Verify that the Runbox Trojan/virus filter has been turned on.
• Instead of downloading your entire email to an email client, you can read it using the Webmail interface located at www.runbox.com. Screen your email carefully before downloading any valid email to your local mail client.
• Check that your anti-virus software has been installed and is running on your local computer. Automatic updates are essential for virus security. When you combine server-side scanning and client-side scanning, you now have two levels.
• Disable message preview in your email client, especially on Windows platforms. Malicious programs can be attached to incoming mail and infect your computer automatically.
• You can ignore or delete messages sent from official Runbox email addresses. Attachments are also allowed. Runbox rarely sends emails to its users, except for payment notifications and responses to inquiries. Users rarely receive attachments in an email from Runbox.
• It is important to be cautious when opening media attachments and graphics. Viral infections can hide in these files.

Also read: Top 10 Free PC Cleaning Software for Windows

3. Symptoms of Virus Infection After Malware Attack

The following warning signs should alert computer users to malware attacks:

• System output slows down
• Pop-ups are bombarding your screen
• Programs that run on their own
• Files multiplying/duplicating on their own
• You can install new files and programs on your machine
• Programs, directories, and files that are lost or damaged

4. Examples of computer virus

Although the web is home to millions of computer viruses and many more, only a handful have been popular enough to infect record-breaking numbers of computers. These computer viruses are widespread examples:

• Morris Worm
• Nimda
• ILOVEYOU
• SQL Slammer
• Stuxnet
• CryptoLocker
• Conficker
• Tinba
• Welchia
• Shlayer

Conclusion – Types of computer virus

A virus can remain dormant on your computer for long periods of time without causing any symptoms. Once the virus infects your computer, it can spread to other computers within the network. Cybercrime includes stealing passwords and records, logging keystrokes, and corrupting files.