How Do Antivirus Programmes Detect Malware?

If you have an antivirus programme, you’ll know that familiar ping to alert you a threat has been blocked. But have you ever wondered how the software knew something was off? These days, malware is extremely sophisticated and hides among ordinary files and downloads. With it blending in so easily, how can it be detected?

That’s where antivirus technology comes in. Equally as sophisticated, it works behind the scenes to monitor everything you do. Every app opened, link clicked or file downloaded is scanned in real-time for anything suspicious.

So how can it do this? Let’s get into the specifics.

 

What Is Malware?

 

Malware is an umbrella term for any kind of software that is designed to harm your system in one way or another. It encompasses viruses and worms which destroy files, spyware to monitor your activities and ransomware where your device is locked and there’s usually a hefty fee involved to get it back.

In the UK alone, four in ten businesses reported some form of cyber threat in the last year. These usually came in the form of phishing, one of the most common types of malware where fraudulent e-mails or links are sent to a person impersonating someone they know. When the e-mail is opened or link is clicked, the device becomes infected with the malware.

Cybercriminals are getting smarter and so are their tactics. As new forms of malware are constantly being conjured up, having an antivirus programme can significantly reduce your chances of falling victim to one.

 

How Is Malware Detected By Antivirus Programmes?

 

Not all antivirus software is created equally and can use different methods to monitor and detect unusual activity on devices. Here’s how most of them will work and how are able to differentiate between normal and suspicious behaviour.

 

Signature-Based Detection

 

Every piece of malware, regardless of what type it is, has code that is attached to it. Think of it almost as like a unique fingerprint. Antivirus companies build databases of these fingerprints and they become known threats.

So when you run a scan, the antivirus will check every file or download against that database and if there’s a match, it will be flagged. Depending on which antivirus you have, the isolated malware will then be deleted, quarantined or blocked.

This method is highly accurate however it requires constant updating to be able to identify new threats as they become available.

 

 

Behaviour-based Detection

 

Behaviour-based detection works a bit differently to the signature-based method. Here, files aren’t checked beforehand but instead, while they are in use or running. If an app tries to do anything suspicious like access your webcam or encrypt files, it’s immediately flagged.

While this method works well for identifying the more advanced threats like ransomware and spyware, it can slow down your device as its quite resource-intensive.

 

AI And Machine Learning

 

With AI constantly evolving, it’s now being used in antivirus programmes too. Machine learning models are trained on hundreds of thousands of files to learn how to identify patterns and trends. Essentially, they learn over time what malware looks like and what it can do.

It can identify the more complex and evolving threats but because it’s still in its early phases, there can be some false positives from time to time.

 

Cloud-Based Detection

 

Cloud-based systems are incredibly powerful and can check thousands of files in real-time. If an unusual file is flagged, it is anonymously sent to the cloud servers of the antivirus company. There, it will be analysed by AI and other existing databases of threats.

This form of detection is highly efficient and doesn’t need to exhaust all of your computer’s resources however it does require an Internet connection to be able to work.

 

What Happens If Malware Is Detected?

 

The next question is, what is the process if malware is identified? The first thing the antivirus will do is isolate it. Once it’s in quarantine, it can’t get away.

You’ll then typically get a notification where you can choose the next course of action whether it be to remove it or ignore it. Depending on what your settings are, the antivirus will then try to repair the file or delete it entirely.

These programmes are probably your best shot at protecting your device and your data, so it’s always worth investing in one. And if you do, always keep it updated regularly to stay up-to-date with new threats.

While free versions can protect you to some degree, they don’t have the same capabilities that paid ones do. With that said, if your antivirus tells you something seems off, it probably is.