What is a computer virus?
A computer virus is a type of malicious program that gets into your computer through email attachments or are hidden inside of other software applications that you have downloaded to your computer. Viruses are primarily created to alter the way a computer functions. Although they cannot damage the physical hardware of a computer system, some viruses have the capacity to render the device completely useless within seconds. Thousands of new viruses are discovered by security experts every week.
How does a computer virus work?
Once a virus has attached itself to a legitimate program on your computer, it can remain dormant without showing any symptoms until the infected program is run, which in turn will cause the virus to be activated. When a virus is activated, it means that it is in the computer’s memory, where it will be able to do a lot of damage such as infecting other applications in the machine. Once the infection phase of the virus is complete, the next stage begins: the destructive phase, where it delivers its payload. Viruses will wait for a certain trigger such as a date before it delivers its payload. This can be the deletion of files all the way to the destruction of the operating system.
Some of the damage a virus can do include:
- Steal passwords and sensitive data
- Log keystrokes
- Corrupt or delete files and folders
- Spam email contacts
- Completely take over your device
- Damage your hard disk
How does a computer get infected with a virus?
In the olden days, viruses were distributed on a floppy disk. Today, as the Internet has matured, computer viruses are spread in several ways.
- The virus can attach itself to legitimate software such as a computer game, PDF file or office document which is then downloaded to a device.
- By clicking on an attachment in an email that is infected with a virus.
- By clicking a malicious link in an email or text message that redirects to an infected webpage which downloads a virus to your computer.
- By clicking on a malicious link in a social media message or post.
- Through external storage devices such as USB sticks.
- A network user visiting an infected site will infect other devices on the same network.
- Some viruses are part of macros in spreadsheets or word processing applications like Microsoft Office.
What are signs or symptoms of a computer virus?
If your computer has been infected with a virus, it will begin to show symptoms that indicate the computer has been infected, and what type of virus it has been infected with:
- Unexpected pop-ups. The popups that suddenly appear when you browse the web are actually coming from adware that’s been installed on your computer. These popups are used to sell fake antivirus programs. Avoid clicking on them as they will actually install different types of malware onto your computer.
- Your search engine changes without your consent. When your homepage is changed or your search engine changes without your consent, you won’t be able to reset it. It means your web browser has been infected with browser hijackers and adware that has been installed on your computer. When this happens, you’ll be redirected to unfamiliar websites and see unwanted advertisements that originate from the viruses that have been installed on your system.
- Your computer and internet speed slows down. Sudden loss of performance is one of the most common symptoms that indicate your computer has been infected by a virus. Your operating system will take longer than normal to start, and software programs will take ages to open. Your internet speed will also slow down considerably. If you have recently downloaded free software, you may have inadvertently downloaded a virus that was attached to the file.
- Antivirus software is disabled. If your antivirus software is disabled, this is a clear sign that your computer has been infected with malware. Antivirus software cannot get disabled on its own. You’re also likely to find that you’re unable to download antiviral software.
- Slow internet. Computer viruses are a major cause of slow internet performance. Some viruses can hog your internet bandwidth by sending out hundreds of spam emails per minute.
- Strange programs: You may suddenly have unrecognized applications on your computer that launch by themselves.
- Programs crashing: If you have a virus, your computer is likely to crash frequently, with programs opening and closing automatically. You may not be able to open your programs and files. You’ll may also see strange messages as you boot.
- Overactive hard drive: If you find that your hard drive is exhibiting a high level of activity and constantly spins even though you’re not using the device, it is highly likely that you have a virus in the machine.
- Password changes: if you’re suddenly no longer able to login to your computer, a virus may be preventing you from logging in.
- Missing files: If you find that certain files and programs have suddenly been deleted or moved around, this is likely to mean that you have a virus on your system.
- Constantly active internet connection: if your internet connection is very active even when you’re not using it, you may have a virus that is transferring messages back and forth across the web.
How can I prevent computer virus infection?
As the saying goes, prevention is better than cure. Installing antivirus software on your system may not be enough to guard your computer against all types of viruses, with thousands being created every single week. Here are crucial tips you can use to protect your computer from being infected by a nasty virus.
- Use strong passwords. Secure your computer with a strong, unique and complex password. You need to make it extremely difficult for your computer to get hacked.
- Stay up to date. Ensure that you have the very latest versions of all applications installed on your devices. Legitimate software vendors regularly update their software to get rid of vulnerabilities that hackers could exploit.
- Install good antivirus software. Antivirus software are not a complete solution, but they can identify and eliminate threats and keep your system protected.
- Enable your firewall. Modern operating systems come with a firewall pre-installed. Be sure to enable it to provide an extra layer of protection against viruses and other online threats.
- Block pop-ups. A pop-up blocker will prevent pop-up ads that can download malware onto your system.
- Beware of phishing emails. Clicking attachments in phishing emails is one of the most common ways to download viruses to your computer. Never click a link or download an attachment in an email unless you are 100% confident of the source of that email.