A computer virus, much like a flu virus, is designed to spread from host to host and has the ability to replicate itself. Similarly, in the same way that flu viruses cannot reproduce without a host cell, computer viruses cannot reproduce and spread without programming such as a file or document.

In more technical terms, a computer virus is a type of malicious code or program written to alter the way a computer operates and 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 in order 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.

A computer virus is a piece of code embedded in a legitimate program and is created with the ability to self-replicate infecting other programs on a computer. Just like how humans catch a cold or flu, it can remain dormant inside the system and gets activated when you least expect it.

A computer virus is developed to spread from one host to another and there are numerous ways on how your computer catches it. It can be through email attachments, file downloads, software installations, or unsecured links.

These viruses can steal your data such as passwords, hacked into your social media accounts or online banking accounts, and even wiped out all your data.

Common Types Of Computer Viruses

Cybercriminals are getting better and better at stealing our confidential data and viruses that are being created are evolving rapidly. There are millions of viruses around the world, but here are some common types you should be aware of:

1. File-infecting Virus

A virus that attached itself to an executable program. It is also called a parasitic virus which typically infects files with .exe or .com extensions. Some file infectors can overwrite host files and others can damage your hard drive’s formatting.

2. Macro Virus

This type of virus is commonly found in programs such as Microsoft Word or Excel. These viruses are usually stored as part of a document and can spread when the files are transmitted to other computers, often through email attachments.

3. Browser Hijacker

This virus targets and alters your browser setting. It is often called a browser redirect virus because it redirects your browser to other malicious websites that you don’t have any intention of visiting. This virus can pose other threats such as changing the default home page of your browser.

4. Web Scripting Virus

A very sneaky virus that targets popular websites. What this virus does is overwrite code on a website and insert links that can install malicious software on your device. Web scripting viruses can steal your cookies and use the information to post on your behalf on the infected website.

5. Boot Sector Virus

These viruses are once common back when computers are booted from floppy disks. Today, these viruses are found distributed in forms of physical media such as external hard drives or USB. If the computer is infected with a boot sector virus, it automatically loads into the memory enabling control of your computer.

6. Polymorphic Virus

This virus has the capability to evade anti-virus programs since it can change codes every time an infected file is performed.

7. Resident Virus

A resident virus stores itself on your computer’s memory which allows it to infect files on your computer. This virus can interfere with your operating system leading to file and program corruption.

8. Multipartite Virus

A type of virus that is very infectious and can easily spread on your computer system. It can infect multiple parts of a system including memory, files, and boot sector which makes it difficult to contain.

The Top 10 Worst Computer Viruses in History

• Klez – $19.8 billion. …
• ILOVEYOU – $15 billion. …
• WannaCry – $4 billion. …
• Zeus – $3 billion. …
• Code Red – $2.4 billion. …
• Slammer – $1.2 billion. …
• CryptoLocker – $665 million. …
• Sasser – $500 million. The Sasser worm was written by a 17-year-old German computer science student named Sven Jaschan.

How does a computer virus attack?

Once a virus has successfully attached to a program, file, or document, the virus will lie dormant until circumstances cause the computer or device to execute its code. In order for a virus to infect your computer, you have to run the infected program, which in turn causes the virus code to be executed.

This means that a virus can remain dormant on your computer, without showing major signs or symptoms. However, once the virus infects your computer, the virus can infect other computers on the same network. Stealing passwords or data, logging keystrokes, corrupting files, spamming your email contacts, and even taking over your machine are just some of the devastating and irritating things a virus can do.

While some viruses can be playful in intent and effect, others can have profound and damaging effects. This includes erasing data or causing permanent damage to your hard disk. Worse yet, some viruses are designed with financial gains in mind.

How do computer viruses spread?

In a constantly connected world, you can contract a computer virus in many ways, some more obvious than others. Viruses can be spread through email and text message attachments, Internet file downloads, and social media scam links. Your mobile devices and smartphones can become infected with mobile viruses through shady app downloads. Viruses can hide disguised as attachments of socially shareable content such as funny images, greeting cards, or audio and video files.

To avoid contact with a virus, it’s important to exercise caution when surfing the web, downloading files, and opening links or attachments. To help stay safe, never download text or email attachments that you’re not expecting, or files from websites you don’t trust.

What are the signs of a computer virus?

A computer virus attack can produce a variety of symptoms. Here are some of them:

• Frequent pop-up windows. Pop-ups might encourage you to visit unusual sites. Or they might prod you to download antivirus or other software programs.
• Changes to your homepage. Your usual homepage may change to another website, for instance. Plus, you may be unable to reset it.
• Mass emails being sent from your email account. A criminal may take control of your account or send emails in your name from another infected computer.
• Frequent crashes. A virus can inflict major damage on your hard drive. This may cause your device to freeze or crash. It may also prevent your device from coming back on.
  
• Unusually slow computer performance. A sudden change of processing speed could signal that your computer has a virus.
• Unknown programs that start up when you turn on your computer. You may become aware of the unfamiliar program when you start your computer. Or you might notice it by checking your computer’s list of active applications.
• Unusual activities like password changes. This could prevent you from logging into your computer.

There are various ways to protect and remove malwares,spywares and viruses from our computers. No one method is enough to ensure your computer is secure. The higher the defense, the harder for hackers to have access to your computer.

Check out these steps to protect your computer

• Install Firewall
• Install Antivirus Software
• Install Anti-Spyware Software
• Use Complex and Secure Passwords
• Check on the Security Settings of the Browser

Install Firewall

A firewall plays the role of a security guard. There are of two types of firewalls: a software firewall and hardware firewall. Each serves similar, but different purposes. A firewall is the first step to provide security to the computer. It creates a barrier between the computer and any unauthorized program trying to come in through the Internet. If you are using a system at home, turn on the firewall permanently. It makes you aware if there are any unauthorized efforts to use your system.
Install Strong Antivirus Software:

Antivirus is a prominent  means to protect the computer. It is software that helps to protect the computer from any unauthorized code or software that creates a threat to the system. Unauthorized software includes viruses, keyloggers, trojans etc. This might slow down the processing speed of your computer, delete important files and access personal information. Even if your system is virus free, you must install an antivirus software to prevent the system from

Install Anti-Spyware Software:

Spyware is a software program that collects personal information or information about an organization without their approval. This information is redirected to a third party website. Spyware are designed in such a way that they are not easy to be removed. Anti-Spyware software is solely dedicated to combat spyware. Similar to antivirus software, anti-spyware software offers real time protection. It scans all the incoming information and helps in blocking the threat once detected.Comodo Antivirus comes with spyware protection built in.

Use Complex and Secure Passwords:

The first line of defence in maintaining system security is to have strong and complex passwords. Complex passwords are difficult for the hackers to find. Use a password that is at least 8 characters in length and include a combination of numbers, letters that are both upper and lower case and a special character. Hackers use certain tools to break easy passwords in few minutes. One recent study showed that a 6 character password with all lower case letters can be broken in under 6 minutes!

Check on the Security Settings of the Browser:

Browsers have various security and privacy settings that you should review and set to the level you desire. Recent browsers give you ability to tell web sites to not track your movements, increasing your privacy and security.

What damage can a virus do?

What does a computer virus do? Some computer viruses are programmed to harm your computer by damaging programs, deleting files, or reformatting the hard drive. Others simply replicate themselves or flood a network with traffic, making it impossible to perform any internet activity.

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Hope this article is helpful to you?