How Does an Anti-virus Software Work?

Anti-virus software is essential on Windows computers in times of burgeoning cyber attacks. For protecting computers, an antivirus program is used as an integral part of multi-layered security strategy.

How an Anti-virus Software Works?

Constant attacks of vulnerabilities for browsers, plug-ins, and the operating system make it important to keep your computer safe using antivirus software..

On Access Scanning:

On-access scanning is a condition when your antivirus software runs in the background on your computer to check every file you open.

When you first open an . EXE file by double-clicking it, it starts checking the program first and then comparing it to known viruses, worms, and other types of malware.

How an Anti-virus Software Works

Standard antivirus programs can also scan your computer to find other types of files including a .zip archive file or a Word document that can contain viruses.

With on-access scanning, the antivirus program scans files whenever they are opened and used.

You can escape on-access scanning while using an anti-virus program, but, we aren’t even recommending this. After your system has been infected, it’s much harder to remove.

Full System Scans:

If you have inadvertently downloaded a virus to your computer, your antivirus program detects it immediately.

So, you don’t have to manually initiate a scan every time when you download something on your computer. Moreover, if you have set on-access scanning at default, you needn’t run a full system scan.

How an Anti-virus Software Works

Full-system scans are useful in cases when you’ve just installed an antivirus program. Running the full system scan ensures that there are no viruses are wreaking havoc on your computer.

You can also run full disk scans when you’re readying to repair the infected files on your computer or inserting its hard drive in another computer and performing a full-system scan for viruses.

Virus Definitions:

Virus definitions are the building blocks of your antivirus software that help them detect malware. The virus definition files comprise signatures for viruses and other malware.

While scanning the files, when an antivirus program detects an infected file that matches a known piece of malware, it stops the file from running. The software then puts the infected file into “quarantine.”

You can change the default settings to let your antivirus program automatically delete the file upon detection or you may allow the file to run anyway.


Heuristics help antivirus programs to identify new or modified types of malware even without virus definition files. Suppose, your antivirus finds that a program running on your system is trying to open and infect every EXE file on your system, the program can detect this program as a new, unknown type of virus.

False Positives

False positives usually happen when an antivirus program flags file infected or malware even if it’s completely safe.

There have been several instances when antivirus companies even flagged Windows system files, popular third-party programs, or their own antivirus program files as viruses.

Even, Heuristics can be sometimes the reason behind the increased rate of false positives. Despite this, false positives are rare and don’t deter your antivirus system from detecting malicious files or malware.

Genelia Timothi