Computer viruses have long been no stranger to those who use computers, they have a long history of development and are constantly changing according to the development of software technology in the world. Computer viruses can damage hard drives, delete data,… with varying degrees of destruction. So what is a computer virus, how does it work to infect?

1. What is a computer virus?

A computer virus, also known as a virus, refers to a piece of program code designed to infiltrate a computer, with the aim of stealing information, deleting data, sending anonymous emails, automatically replicating to spread the virus. .

Previously, viruses were written for testing purposes, but later on, viruses became more dangerous when they were directed to steal users’ personal information, creating opportunities for hackers to take control. control or other actions for gain. In addition to these negative effects, the signs that a computer is infected with a virus are also its effects on the computer.

Currently, the Windows operating system ranks first in the list of infected operating systems, due to the large number of Windows users, the number of viruses on this operating system is also constantly increasing, with many different variations.

2. Paths of spread of computer viruses

Viruses can infect in many different ways and are becoming more and more sophisticated. There are two ways to spread viruses: through the Internet and through devices attached to computers. Here are the most common transmission routes of computer viruses.

External devices

Viruses can spread to computers through USB, phones, external hard drives. If these devices have viruses, the computer will become infected with viruses if protection measures are not taken.

Viruses infecting the Internet

The most common form of infection via the Internet today is the main method.

Download files or software:  When downloading files from the network to your computer, if the file is infected with a virus, it will most likely spread to your computer.

Viruses infect via email

Email is the traditional way to communicate and exchange with each other to this day. The virus will find all email contacts in the list and automatically send bulk mail. And when email recipients click on attachments, links, or in the email content itself, the virus quickly spreads exponentially.

So you should be careful with attachments and links in emails, if the mail is sent from an address you don’t know or trust, delete it instead of curiously clicking on the link or file in that email.

Online Advertising

If you click on an ad that contains malicious code, it can infect your computer with a virus. Cyber ​​attackers insert malicious code into ads and place ads on trusted websites to easily lure users to click.

Malicious website

When you click on links or download files on websites that are infected with malicious code, you can also be infected with viruses.

Link, file scam

These types of links and files can appear anywhere on the Internet, from websites, social networks, chat applications.

Viruses spread via Bluetooth, NFC

If you share data with other devices via mobile wireless connections such as Bluetooth, NFC, it can also expose your device to viruses. So turn off these connections when not in use or only share with devices you feel safe.

Viruses spread through security holes, operating system backdoors

In fact, if you look at the details, this way of infection is still through the above 3 ways. That is, when the operating system has a backdoor or security hole, the hacker still needs to be able to access the computer (via external devices, malicious links/files) to spread the virus.

3. Identify a computer infected with a virus

So how do you know if your computer is infected with a virus? There are often some basic telltale signs such as the computer running abnormally slow, the computer screen constantly crashing like the blue screen error , … then you can think of a virus infection problem.

4. How viruses work

A computer is operated by instructions in the form of machine code to perform a certain task. Machine code is a sequence of binary numbers and is programmed to lead to defined repetitive tasks organized into separate modules called routines, and when the routine is executed, the running program executes the instruction. to that routine to execute. A routine has an entry point structure where it starts, and an exit point returns control to the caller when it’s done.

The virus is written as a routine, which modifies the address parameter of the instruction pointing to its address, and when the virus terminates, passes control to the called routine of the program. Computer viruses only work as code.

5. How to prevent computer viruses?

Install anti-virus software

Installing anti-virus software is considered a traditional method of computer protection and should be done on any computer. The use of anti-virus software is very necessary for any computer user because of its convenience and safety in information security.

The famous software that you can trust to install on your computer are: Bkav, Kaspersky, Avira, AVG, ESET, Avast, BitDefender…