Key Takeaways
- A computer virus is a piece of malicious code that attaches itself to legitimate programs to spread across devices and steal data. But how do they work on a computer? Keep reading for more insights!
- Types of computer viruses vary in behavior and effects, but KWT Tech Mart shows you nine common ones that you need to focus on the most! Below are details of each of them!
- Are you ready to protect yourself from Viruses? If the answer is yes, we have you covered about how to do it below! Let’s discover now!
What is Computer Virus?
As our daily lives become more dependent on computers and the internet, computer viruses have become a major issue for both people and their businesses.
So, the question is: What is computer virus? A computer virus is a piece of code that is hidden in a legitimate application and is designed to copy itself and attack other programs on the same device. It can stay dormant in the system and wake up when you least expect it, just like how people get colds and flu.
What is Computer Virus?
A computer virus is designed to move from one host to another, and there are several ways for it to get on your machine. It could be through linked files, email documents, software installs, or unsafe links. These viruses can enter your networking sites or online banking accounts and steal data like passwords. They can also delete all of the data you have entered.
8 Common Types of Computer Viruses You Should Know
Computer viruses are classified by their function, assault method, or harm.
Computer viruses come in a lot of different types, and each one has its own set of traits and effects on computers. These types of computer viruses can be grouped by how they work, how they attack computers or the damage they do. But, with KWT Mart’s exp. You should keep these popular types in mind:
1. Direct Action Virus
Direct-action viruses act immediately upon execution, targeting specific file types like .COM and .EXE in a directory. Unlike other viruses, they do not remain in memory after execution. These malware types disrupt network activities, delete files, or redirect searches.
Signs of infection include frequent pop-ups, corrupted files, or unexpected system behavior. Direct action viruses spread via infected email attachments or executable files and can lead to significant data breaches.
2. Memory-Resident Virus
Memory-resident viruses infiltrate your computer’s RAM, where they remain active as long as the system is running. These types of viruses in computers infect files accessed during the session, often slowing your computer or causing crashes.
Their presence can disable antivirus programs, making detection and removal challenging. They spread through infected programs, external drives, or downloaded files, leaving compromised systems at risk of data loss and reduced functionality.
3. Overwriting Viruses
Overwriting viruses are particularly destructive, erasing data in infected files by replacing it with random code. These viruses don’t alter the file size, making them difficult to detect without specialized tools.
Once infected, the only way to eliminate the virus is by deleting the affected files, resulting in permanent data loss. These viruses often spread through email attachments or unsecured file-sharing networks.
4. Boot Sector Viruses
Boot sector viruses compromise the section of a drive responsible for loading the operating system. Historically common on floppy disks, they now spread via USB drives or other external storage devices.
Boot sector viruses compromise the drive's operating system-loading portion.
Symptoms include system startup errors, missing files, or sluggish performance. Severe infections might prevent the computer from booting altogether, displaying error messages instead.
5. Macro Viruses
Macro viruses exploit the scripting features in programs like Microsoft Word or Excel, embedding themselves in documents. Opening an infected file triggers the virus, which can spread through email attachments or shared files.
These viruses corrupt text, add unsolicited changes and even use the victim’s email account to propagate. They’re cross-platform, affecting Windows, macOS, and Linux systems alike.
6. Polymorphic Virus
Here an examples of computer viruses: Polymorphic viruses adapt to evade antivirus detection by altering their code with each infection. These clever mutations involve encrypting or compressing their payloads, creating a challenge for traditional security measures.
Such viruses can slow systems, steal sensitive information, and corrupt files. They spread through downloads, malicious links, or infected email attachments.
7. FAT Virus
Damage to FAT might disable files or crash the system.
The FAT virus targets the file allocation table, a critical part of your computer's file storage system. Damage to the FAT can make files inaccessible or cause a complete system failure. These viruses often come from infected programs or downloads. Symptoms include missing data or frequent crashes, which may require reformatting the hard drive to resolve.
8. Multipartite Virus
Multipartite Virus is a types of virus in computer that is extremely spreadable and has the potential to propagate across your computer system quickly. Because it may infect numerous components of a system, including memory, files, and the boot sector, it is difficult to confine once it has successfully spread.
9. Web Script Viruses
Last but not least, Web script viruses hijack browsers by embedding malicious code into web pages. They alter browser settings, redirect users to harmful sites, or steal sensitive data like passwords.
These viruses are commonly encountered through infected links, pop-ups, or untrustworthy websites. Safeguards like secure browsing habits and updated antivirus software can minimize the risk.
What Causes Computer Viruses?
What Causes Computer Viruses?
Computer viruses result from specific vulnerabilities, user actions, and intentional malicious activities. Here are common causes:
- Malicious Downloads: Viruses often originate from downloading software, files, or email attachments from unreliable sources. These can carry hidden malware activated upon opening.
- External Devices: Using infected USB drives or external hard drives allows viruses to spread into your computer system.
- Clicking Unsafe Links: Phishing scams or fraudulent advertisements redirect users to malicious websites that deliver viruses.
- Outdated Software: Not updating your operating system or applications leaves gaps in security, providing an entry point for viruses.
- Public Networks: Connecting to unprotected Wi-Fi networks increases exposure to malware attacks. Hackers can exploit these networks to plant viruses on your tech device.
- Social Engineering Tricks: Criminals using fake alerts or fraud trick people into running dangerous programs or giving out private data.
How Do Computer Viruses Work?
There are so many ways that viruses hack your computer. But almost of types of computer viruses typically spread by attaching themselves to legitimate files or programs. When the virus becomes active, it typically happens when the infected file is opened or run, and its harmful code is run. Certain viruses don't do anything until a certain event or action activates them.
There are several ways viruses hack computers.
They make copies of themselves in other files or devices and spread them through networks, email links,... A lot of viruses hide their identities using tricks like encryption or diversity, thereby making it harder for security software to find them. Viruses can steal sensitive data, slow down computers, turn off security software, or even lock files so that they can't be opened, like in ransomware attacks.
How Do Viruses Spread?
Viruses can spread in many ways, often by taking advantage of faults in computer systems, networks, or people's actions. A person starts a harmful file without knowing it is there; this is one of the most usual ways. People are more likely to click on these emails because they look like they came from real people or services they trust.
Another common way is through harmful websites or ads (also called "malvertising") that, when a person visits them, download and install malware on their device without their permission. When plugged into a computer that has viruses, USB drives and other external storage devices can also spread viruses to other devices. Phishing and other forms of social engineering get people to download or run dangerous files.
Computer Viruses vs Malware
Computer Viruses vs Malware
Computer viruses and malware are terms often used interchangeably, but they are not the same. A computer virus is a specific type of malware designed to replicate itself and spread from one computer to another, typically by attaching itself to executable files or documents. When a user opens an infected file, the virus activates, and the cycle continues, often disrupting system performance or corrupting files.
Malware, short for "malicious software," is a broader category that includes any software intentionally designed to cause harm. This encompasses not only viruses but also worms, trojans, ransomware, spyware, adware, and other types of harmful programs. While all viruses are malware, not all malware are viruses. For example, ransomware locks users out of their systems and demands a ransom, while spyware secretly monitors a user’s activity.
To sum up, viruses are one type of malware. Malware can also include a lot of other harmful programs. It plays a role in understanding this difference to come up with effective defense and prevention methods.
Signs of Computer Virus
Signs of Computer Virus
- Slow Performance: If your computer suddenly becomes sluggish, it may be due to a virus running processes in the background. This is often a result of malware using up system resources.
- Frequent Crashes or Freezes: A computer that frequently crashes or freezes could be infected with a virus. Malicious software can destabilize your operating system and cause these issues.
- Unusual Pop-Ups or Ads: Excessive pop-up ads or strange messages may indicate an infection, especially if they appear out of nowhere, even when you're not browsing the web.
- Missing Files or Programs: Viruses often delete or hide files so that you might notice files or programs disappearing from your system.
- Antivirus Software Disabled: Some viruses can disable or bypass antivirus software. If your antivirus stops working unexpectedly, it might be due to a virus.
- New or Unfamiliar Icons: Some viruses install unfamiliar programs on your system, which can result in strange new icons appearing on your desktop.
How to Remove a Computer Virus?
How to Remove a Computer Virus?
1. Disconnect from the Internet
To prevent the virus from spreading or stealing data, immediately disconnect your computer from the internet by disabling Wi-Fi or unplugging the Ethernet cable.
2. Enter Safe Mode
Boot your computer in Safe Mode. This minimizes the number of programs running and allows you to remove malware that may not be active in this mode. To enter Safe Mode, restart your computer and press F8 (for Windows) or hold Shift while restarting (for macOS).
3. Run Antivirus Software
Use reliable antivirus software like Norton to run a full system scan. Make sure your antivirus definitions are up to date. If you don’t have antivirus software installed, you can use a free tool like Malwarebytes to remove the virus.
4. Delete Suspicious Files and Programs
After the scan, follow the instructions provided by the antivirus program to delete any identified malware. Be sure to remove any unfamiliar or suspicious software from your system through the Control Panel (Windows) or System Preferences (macOS).
5. Restore Affected Files
If any important files were compromised, check your backup and restore them. If you don’t have a backup, tools like Recuva can help recover lost files.
6. Update Your System
Ensure your operating system and all software are fully updated. Viruses often exploit security flaws in outdated software. Keeping everything up to date minimizes the risk of further infections.
7. Change Passwords
After cleaning your system, change your passwords for online accounts, as viruses often attempt to steal login credentials.
By following these steps and using the right tools, you can effectively remove a virus and prevent future infections.
How to Protect Yourself From Computer Viruses
Installing good protection software is the first thing you should do to keep your computer safe from viruses. If you keep your security software up to date, it will be able to find the newest bugs.
You should also keep your operating system and apps up to date so that hackers can't take advantage of security flaws. Another important thing to do is to stay away from downloads and email files that look sketchy, as these are common ways for viruses to get in.
Update your operating system and applications to prevent hackers from exploiting security weaknesses.
Turning on a router adds an extra layer of protection by stopping people who aren't supposed to be there from getting into your system. USB files and other portable devices can carry bugs, so be careful with them. If you back up your files regularly to the cloud, like Google Drive, your important files will be safe from computer viruses.
Last but not least, strong passwords and learning about online risks like phishing can help you stay away from common mistakes that can get you viruses.