Prologue
Computer viruses are like digital troublemakers, it sneaks into your computers, mess things up and can even steal your important stuff. In this guide, we will break down what viruses are, how they spread, what signs to look out for, and how you can protect yourself. We will also talk about antivirus programs and whether you need extra tools or measures to stay safe.
Virus VS Worm
Viruses and worms are two distinct type of malware. The key difference of both, is that virus needs a host file or program to attach itself to relies on human action to spread. On the other hand for worm, it is a self-replicating program and can spread automatically across networks without any user interaction. Here is the summary of differences between virus and worm:
Virus
- Spread when the user transfer the infected files/program to other computers
- Cannot be easily removed from the system
- Inserts into a file or executable program
- Deletes files or modifies files. Sometimes, it also changes the location of the files
- Spreads with uniform speed as programmed
Worm
- Use a network to replicate itself to other computer system without user intervention
- Can be easily removed from the system
- Exploits a weakness in application or operating system
- Does not delete or modify files but it consumes system resources like CPU, memory or network bandwidth, slowing down the system and causing the entire system or network to crash
- Spread more rapidly than virus
Types of Virus
- Boot sector virus
- Infects the boot sector of a floppy or Master Boot Record (MBR) of the hard disk
- Typically spread through removable media
- Difficult to remove and often require entire system to be formatted
- Direct action virus
- Also known as non-resident virus
- Replicate and infect files in folder
- Attack certain types of files
- Resident virus
- Most common virus
- Save itself in the computer’s memory and cause file and program corruption
- Able to attach to antivirus program, infecting what the antivirus scan for sign of viral infection
- Hard to remove from system
- Multipartite virus
- Can attack both boot sector and execution files at the same time
- Known as hybrid virus as it combine the characteristics of file infectors and boot sector viruses
- Overwrite virus
- Overwrites the content of a file, causing it to lose it original content
- Infect folders, files or even programs
- Remove the virus by deleting the infected files
- Polymorphic virus
- Can adapt to various defences
- Constantly modify itself to avoid detection but retain the same program after each infection
- Spreads through spam and infected website
- Complex and challenging to detect
- Remove it is time-consuming, complex and costly
- File infector virus
- First infects a single file and spread to another files
- Slows down programs and damage system files when users run it
- Example: CIH virus and Melissa virus
- Spacefiller virus
- Attempts to install itself by filling in empty spaces in a file
- Known as cavity virus
- It will neither affect the size of the file nor can be detected easily
- Macro virus
- Infect documents and damage the computer
- Macro is used to create program in Microsoft Word, Excel and etc
- Spread rapidly as infected documents are shared on network and downloaded from website
- Example: Concept virus and Melissa virus
Signs and Symptoms of Virus
Spotting a computer virus early is important to protect the data and system. Viruses often cause noticeable changes in how the computer or system behaves, but the exact symptoms can vary depending on the type of virus. Understanding the common warning signs can help to react quickly and prevent further damages. Here are the common signs and symptoms of infections of computer virus:
- Computer restart itself often
- Time taken for computer system to open application become longer
- Application does not start
- Files duplicating on their own
- New files or programs in the computer
- Getting too many pop-up windows on the screen
- Corruption of data
- Crashing of device
- Uncommon error message, distorted menus and dialogue boxes
- Opening of unwanted website
How Do Virus Spread
Viruses can spread in many ways, often taking advantage of different methods to reach new devices. Understanding how viruses move between systems is key to preventing infection and minimizing damage. Here are the common methods and technique virus can be spread:
- Spam emails/email attachments
- When a virus file is downloaded from the internet
- When an infected file is copied from USD, DVD and other medium
- Pirated software
- Unsecured websites
- Online ads
Users unknowingly spread computer virus by sharing infected files or sending emails with virus attachments in the emails. Morever, a virus cannot be spread without a human action (such as an infected program). In short, a virus may exist on your computer but it cannot infect unless a user run and open the infected program
Ways to Protect Computer from Virus
Protecting your computer from virus is essential for keeping data and system safe and running smoothly. There are several effective methods to prevent infection, from using security software to practising safe online habits.
- Always scan USB drive or CD/DVD with antivirus software
- Do not use pirated software
- Use firewall acts as a security guard
- Do not download data from non-trusted website
- Install antivirus software and keeping it up-to-date
- Protect WiFi with encrypted password
- Avoid suspicious links and email attachments
- Run regular schedules scans with antivirus software
- Make regular backups of data on different media
Steps to Take When You Think Your Computer Has a Virus
If you think your computer might be infected with a virus, it’s important to stay calm and take the right steps. Acting quickly can help you identify the issue, prevent further damage, and get your system back to normal. So here are the necessary and immediate actions to take in order to remove malware from spreading:
- Disconnect the suspected computer system from the internet as well as the local network
- Start the system in safe mode or Windows boot disk if it display any problems in starting
- Take back up all data to an external drive
- Install antivirus if you do not have installed
- Perform a full system scan