What is anti-virus and how does it work?

Anti-virus software

In today's world, most of the time we all spend time on the Internet either for work or for personal activities. So, there have possibilities that any devices could get infected with many viruses within minutes of connecting it to the internet. Similarly, a system without an antivirus would also get infected by viruses coming in through devices connected to it or via spammy links that are sent across through emails or chats if the devices don't have an effective antivirus software installed on. That's why we all need antivirus software for our device and data protection. In this article, we will discuss deeply regarding antivirus software and its usabilities that will help you to understand how important they are.

What is Anti-Virus Software?

Antivirus software is a class of program designed to prevent, detect and remove malware infections on individual computing devices, networks, and IT systems. Here, malware means it's any piece of software that was written with the intent of doing harm to data, devices or to people. Viruses, Trojans, Spyware, Worms and the like, what you're really hearing is the talk of different kinds of malware.

You can also learn more from our another article about malware.

Actually, antivirus software is designed to detect and remove viruses from systems, it can also protect against a wide variety of threats, including other types of malicious software, such as keyloggers, browser hijackers, Trojan horses, worms, rootkits, spyware, adware, botnets, and ransomware.

These tools are critical for users to have installed and up-to-date because a computer without anti-virus software installed will be infected within minutes of connecting to the internet. The bombardment is constant, with anti-virus companies update their detection tools constantly to deal with the more than 60,000 new pieces of malware created daily.

Which types of performance can offer these software tools?

  • Scan specific files or directories for any malware or known malicious patterns

  • Allow you to schedule scans to automatically run for you

  • Allow you to initiate a scan of a specific file or of your computer, or of a CD or flash drive at any time.

  • Remove any malicious code detected –sometimes you will be notified of an infection and asked if you want to clean the file, other programs will automatically do this behind the scenes.

  • Show you the ‘health’ of your computer

All these tools will function at best label if you have the best, up-to-date security software installed to protect your computers, laptops, tablets, and smartphones because new viruses are constantly being created by computer hackers every day every minute. Since new viruses are frequently distributed, It’s important to keep your antivirus software's virus database up-to-date. This database includes a list of "virus definitions" that the antivirus software references when scanning files. Fortunately, most antivirus programs automatically update the virus database on a regular basis.

Paid and Unpaid Antivirus Software

Antivirus software can either be free or paid. There are some basic differences between the free and paid versions. Free antivirus software mostly happens to be programmed to do signature-based detection, as per which malware detection happens matching signatures with an existing list of identified signatures. Some vendors, such as Microsoft, AVG, Avast, and AntiVir offer free antivirus software for home use.


On the other hand, paid antivirus programs use the much more advanced heuristic technique to capture advanced threats as well. This would include even sophisticated zero-day threats. Paid antivirus programs work by executing malicious files in a virtual space, through sandboxing, an advanced method of containment. Antivirus companies have to continually keep up-to-date with the latest pieces of malware, releasing definition updates that ensure the malware is caught by their programs. Antivirus labs use a variety of tools to disassemble viruses, run them in sandboxes, and release timely updates that ensure users are protected from the new piece of malware. Example - Kaspersky, Quick-Heal, Avast and McAfee etc.

Comodo Antivirus

Comodo Antivirus for Linux (CAVL) offers the same great virus protection as our Windows software with the added benefit of a fully configurable anti-spam system. It also uses cloud-based behavior analysis of unknown files to provide unrivaled protection against zero-day malware. The powerful AV engine is complemented by a highly configurable mail gateway to filter spam and block email-borne threats.

Features -

  • Proactive AV protection intercepts all known threats

  • Automatic updates for the most up-to-date virus protection

  • Includes scan scheduler, detailed event viewer, and custom scan profiles

  • Mail filter is compatible with Postfix, qmail, Sendmail and Exim MTA's

  • Install and forget. No annoying false alarms, just solid virus protection.

  • Detects and eliminates viruses from Linux based laptops and desktops

  • Mail gateway blocks email-borne viruses and spam

  • Features on-access, on-demand, and cloud-based scanning

  • Virus definitions updated multiple times per day

  • Simple to use: install and forget while Comodo Antivirus protects you in the background

How does Antivirus Work?

An antivirus program works by scanning files, directories or the whole system/device itself for malicious files or programs. The software scans the file comparing specific bits of code against information in its database and if it finds a pattern duplicating one in the database, it is considered a virus, and it will quarantine or delete that particular file. Any malicious code that's detected would be notified to the user and when asked to clean, the antivirus would clean it. Thus, the antivirus software keeps the system free of malware and thus prevents data theft and other serious damages, and it prevents the system from slowing down due to malware infection. An antivirus software thus improves system performance on the whole.

Antivirus programs combine different techniques to actively protect against the different types of threats.

Signature-based detection

This is most common in Traditional antivirus software that checks all the .EXE files and validates it with the known list of viruses and other types of malware. or it checks if the unknown executable files show any misbehavior as a sign of unknown viruses. Files, programs, and applications are basically scanned when they in use. Once an executable file is downloaded. It is scanned for any malware instantly. Antivirus software can also be used without the background on access scanning, but it is always advisable to use on access scanning because it is complex to remove malware once it infects your system

Heuristics-based detection

Antivirus programs also employ heuristics. Heuristics allow an antivirus program to identify new or modified types of malware, even without virus definition files. For example, if an antivirus program notices that a program running on your system is trying to open every EXE file on your system, infecting it by writing a copy of the original program into it, the antivirus program can detect this program as a new, unknown type of virus.

Behavioral-based detection

Behavioral detection observes how the program executes, rather than merely emulating its execution. This approach attempts to identify malware by looking for suspicious behaviors, such as unpacking of mail code, modifying the hosts file or observing keystrokes. Noticing such actions allows an antivirus tool to detect the presence of previously unseen malware on the protected system. As with heuristics, each of these actions by itself might not be sufficient to classify the program as malware. However, taken together, they could be indicative of a malicious program. The use of behavioral techniques brings antivirus tools closer to the category of host intrusion prevention systems (HIPS), which have traditionally existed as a separate product category.

Sandbox-based detection

It functions most likely to that of the behaviorally based detection method. It executes any applications in the virtual environment to track what kind of actions it performs. Verifying the actions of the program that are logged in, the antivirus software can identify if the program is malicious or not.

Cloud-based detection

Cloud-based detection identifies malware by collecting data from protected computers while analyzing it on the provider’s infrastructure, instead of performing the analysis locally. This is usually done by capturing the relevant details about the file and the context of its execution on the endpoint and providing them to the cloud engine for processing. The local antivirus agent only needs to perform minimal processing. Moreover, the vendor’s cloud engine can derive patterns related to malware characteristics and behavior by correlating data from multiple systems. A cloud-based engine allows individual users of the antivirus tool to benefit from the experiences of other members of the community.

Data Mining

This is one of the latest approaches in malware detection that security vendors now provide with their antivirus and antimalware products. A series of features of files are extracted from files, and then data mining and machine learning algorithms are used to classify the behavior of a file and detect whether it has malicious intent or not. This is particularly helpful in detecting and defeating the newest forms of malware in the wild.

Types of scaning of an Anti-virus software

Originally, antivirus programs just offered a regular scanner that searched through the hard drive, looking for known viruses. But modern security solutions offer a whole range of scanning options, these are -


A conventional scan is either run when the user requests it or at a scheduled instance that the antivirus sets up. This type of scan searches the contents of the disks, directories, and files, as well as boot sectors and system components.

Real-Time Protection

Real-Time Protection also is known as memory-resident scanning or background guard. This type of scanning refers to the automatic protection that almost all modern antivirus programs offer. It basically monitors the system for any suspicious activity in real time, while data is loaded into the active memory.

Smart Scans

These refer to an approach where an antivirus only scans selected files, that are more suspicious to be altered or infected. Smart scanning lowers the need for system resources while protecting against the more common types of viruses, threats, and risks.

Startup Scanning

The software often comes with a special program that is designed to run every time the PC is booted up. It does a quick scan of the boot sectors and critical system files, instead of a full disk scan that takes a long time to finish. This comes in particularly handy to catch boot sector viruses before they get a chance to spread.



In the end, we suggest that full-system scans can be useful for some things, however. A full system scan is helpful when you’ve just installed an antivirus program - it ensures there are no viruses lying dormant on your computer. Most antivirus programs set up scheduled full system scans, often once a week. This ensures that the latest virus definition files are used to scan your system for dormant viruses. These full disk scans can also be helpful when repairing a computer. If you want to repair an already-infected computer, inserting its hard drive into another computer and performing a full system scan for viruses is useful. However, you don’t usually have to run full system scans yourself when an antivirus program is already protecting you - it’s always scanning in the background and doing its own, regular, full-system scans.

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