What is antivirus software and do you still need it in 2026?

Antivirus (AV) software is a program designed to detect, isolate, and remove malicious code (also known as malware) from a computer system. When active, it will monitor traffic to and from a device and scan files, applications, and other content.

Most antivirus software uses databases of malicious signatures, built over time by cybersecurity vendors, to detect suspicious code and malware variants that have already been recorded.

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Malware signatures associated with today’s threats are added to these databases, providing a digital fingerprint for AV software to check. However, signature-based databases need to be constantly updated as new malware strains are discovered and as developers tamper with their creations to avoid detection (or release polymorphic malware that changes its own code signatures over time, a problem exacerbated by the abuse of AI).

Modern AV software will often also employ heuristic analysis methods to detect as-yet-unknown, new, and altered malware strains.

If a file is matched to or detected as similar to a database entry, it will be deemed malicious, and users will be alerted to a potential infection. Files can then be quarantined for further investigation or deleted entirely, although false positives sometimes occur.

Antivirus software can protect you against a variety of threats, including:

• Malware: Computer viruses self-propagate to steal data, damage systems, and maintain persistence. Worms spread through system networks or via email as malicious attachments. Trojans disguise themselves as legitimate programs to perform surveillance, download and execute additional malware, and steal information or banking details. These types of malware can be detected by most antivirus programs.
• Ransomware: Ransomware deserves a particular mention as one of the most damaging types of malware. Ransomware encrypts systems, prevents users from accessing their files and services, and demands payment in return for decryption.
• Spyware: Spyware, also known in its worst forms as stalkerware, is unethical, privacy-invading software that spies on device users, collecting data including browser activities, emails, communication, and social media activity.
• Nuisanceware: Adware unscrupulously pushes adverts to a user’s system to generate illicit revenue, and you may also come across unwanted programs that clog up computing memory, resources, and battery. While not often dangerous, these programs can be extremely annoying.
• Phishing: Many antivirus solutions can scan messages you receive in real time or check websites for legitimacy, alerting you to malicious domains, scams, and more.

Antivirus software, whether free or premium, isn’t a one-stop solution to every threat. For example, it will not protect you from social engineering attempts, in which attackers use the information they have on you or your contacts to obtain account credentials. 

It also will not stop physical device theft, zero-day vulnerabilities being exploited in the wild, or sophisticated phishing attempts, such as recruitment scams, which often don’t display the typical red flags that alert cybersecurity solutions to potential fraud.

Also: I tested NordVPN’s free scam checker with real phishing emails – here’s how it fared

It also won’t likely flag ClickFix attacks, which dupe victims into hacking themselves.

Functionality varies depending on the software you choose. However, features often include:

• Scanning: Users can manually scan their devices or schedule system checks to run automatically. Alternatively, AV products often offer real-time background scanning capabilities that check new files, archives, and browser activities for potential threats. Users can select individual files, drives, or full systems for scanning.
• Web browsing: Real-time monitoring for internet-based threats can be enabled to protect users from phishing attempts, malicious websites, suspicious executable file downloads or execution, unintentional drive-by downloads, and more.
• Firewalls: Modern operating systems include a firewall, a network monitoring system that blocks traffic based on set rules. Unauthorized or suspicious connections can be stopped to prevent intrusion.
• VPNs: Some AV products now offer an optional, built-in VPN. A VPN can be a useful addition for hiding your IP address, encrypting your communication with online services, and preventing third-party monitoring and tracking.
• Parental controls: These may include blocking adult content and monitoring keywords.
• Junk clean-up and system optimization: Bolt-on AV software features can include cleaning up junk and unnecessary files, freeing up space on your PC or mobile device.
• Payment protection: AV products may include a feature that monitors visits to suspected fake banking or payment provider websites and warns you if you are about to enter your details on a malicious site.
• Automatic updates: AV software is often updated frequently, which may include updates to signature databases and new security features.
• Wi-Fi monitoring: An AV product may also monitor which Wi-Fi access point your device connects to to warn you if it is not secure, such as an open hotspot in public areas or hotels.

The terms antivirus and anti-malware are often used interchangeably, although antivirus software generally focuses on preventing infections on your PC or mobile device, whereas anti-malware solutions may be more geared toward deep scans and malware removal. Both categories, however, are designed to protect computer systems.

Fraudulent emails, SMS messages, fake websites, and shared resources — such as USB drives or files — can all be used as avenues for malware deployment.

One of the most common avenues for attack is phishing emails that may appear to be from your bank, tax offices, or well-known brands. They lure victims into clicking suspicious links or downloading malicious attachments that contain or fetch malware.

Also: The best malware removal software of 2026

Other common infection vectors include malicious or compromised websites, drive-by downloads, software bundles containing nuisanceware or malicious programs, and apps promoting fake cryptocurrency or investment schemes.

There are signs that malware may have landed on your PC or mobile device. These include:

• Poor performance: One of the first indicators that something isn’t quite right on your PC is a change in typical performance, such as high CPU load, freezes, crashes, or lags during browser sessions. When it comes to your handset, similar symptoms may occur, alongside reduced battery life.
• Pop-up windows and browser redirection: If you are experiencing ads bombarding your screen or unexpected browser redirection, this may be a sign that your browser sessions are being manipulated, or adware is on your system.
• PC and device changes: If programs you are not familiar with suddenly appear, your browser’s home page changes, or settings are tweaked without your knowledge, these could also be indicators of infection.
• Loss of storage space: If your hard drives are filling up for no apparent reason, it could mean you have been compromised.
• Reports of unusual communication: If friends, colleagues, or associates ask you about emails or messages you have allegedly sent that appear to be suspicious, this could indicate that either your device is compromised or an account belonging to you has been hijacked.
• Locked screens: A typical sign of ransomware, in particular, is the inability to access your system beyond the home screen, where a ransom note demanding payment will be displayed. In these cases, your files are likely encrypted and might not be recoverable without a ransomware decryptor or backup.
• Existing antivirus solutions: If your existing antivirus software or firewalls have been disabled without warning, this is a common indicator of malware infection.

On desktops, Microsoft Defender is an anti-malware component of the Windows operating system, and on Apple’s MacOS, XProtect is the default, built-in cybersecurity solution. Add to the mix email services that filter out phishing and spam, alongside browser-based security and alerts, and you may ask yourself whether a standalone antivirus is even necessary.

While each tool is important, and in many cases, default antivirus protections will weed out the most common threats and malware strains, this might not be enough to protect you from new variants, vulnerabilities, advanced phishing campaigns, or online threats.

Mobile threats, too, should be treated just as seriously. Malicious apps and malware could lead to surveillance, monitoring, the download of nuisanceware and adware, data theft, or financial crime.

Also: Is spyware hiding on your phone? How to find out and remove it – fast

Antivirus software should be considered a valuable, active layer of defense that provides real-time threat monitoring, file scanning, and oversight you won’t always have with default antivirus solutions. Regarding mobile threats, an antivirus app can also detect and quarantine malicious apps before they can hijack your smartphone or tablet.

It’s better to have an extra security tool at your disposal than one too few. Whether or not you pay for it, however, is up to you.

Most antivirus products are either free or available on a subscription after a trial, with discounts if you pay for the full term upfront. Free antivirus software offered by reputable vendors has all or most of the core functionality required to protect your PC or phone.

According to Security.org’s latest antivirus usage study, two-thirds of US residents use antivirus software on at least one device. Free antivirus usage has risen to 61%, while users opting for paid options have dropped to 36%. That’s hardly a surprise when both free and premium AV bundles often use the same malware databases and detection tools.

Also: Why you don’t need to pay for antivirus software anymore

The most impressive features of modern AV products are kept behind a paywall, but free solutions provided by cybersecurity vendors are not designed to be detrimental to user security. After all, some form of antivirus is better than none.

If there are features you absolutely must have (such as a VPN, parental controls, and multi-device coverage), most AV solutions are affordable, and you should consider signing up.

The average consumer doesn’t necessarily need to pay for a premium antivirus. Businesses, however, should seriously consider the extra features and security layers offered by premium AV software suites.

You should consider what type of antivirus product suits your needs. Real-time scanners are among the most useful features of an AV product, and you should certainly select one that offers this protection. However, adequate security cannot rely solely on scans and malware signature databases. They must be constantly updated to remain effective.

Usability and the potential impact on PC or mobile performance should also be considered. For example, if you are running an older machine, a lightweight AV product may be more suitable than robust, business-grade software.

If you are looking to subscribe to a premium option, it is also important to decide how many devices you need protection for, whether this is just for one PC or a mobile device, or whether you need a family plan.

No antivirus product is a catch-all security solution, so it should be considered an important aspect of protecting your devices alongside general awareness, education, and caution.

• Stay wary: If an email looks suspicious, trust your gut, as it might be a phishing attempt. If you receive a message from what appears to be a trusted source that also contains a link or attachment, don’t click or download. Instead, verify the email is legitimate through another communication channel first.
• Website downloads: Downloading files from dubious websites, such as crack, warez, or pirate domains, is usually asking for trouble, as these files will often be malicious and may contain Trojans, keyloggers, or ransomware.
• Third-party apps: It is generally recommended to download apps only from sources with their own security and verification processes, such as Google Play or the Apple App Store. If you download an app from another source, you can’t know whether the software is legitimate.
• Firewalls: You should keep your operating system’s firewall software enabled at all times. A firewall is your first line of defense against cyberattacks.
• VPNs: You should use a VPN when you are browsing online. It won’t protect you against malware in most cases, but it will disguise your online activity, prevent monitoring, and may also include alerts that warn you when you are visiting a suspicious website.
• Wi-Fi: Public, unsecured Wi-Fi hotspots should be avoided, as they may be honeypots — fake hotspots — that allow threat actors to monitor your activity, steal data, and potentially redirect you to malicious websites. Stick to secure spots or cellular connectivity whenever you can, and if you cannot, use a VPN.
• Backups: Make sure you back up valuable content on your devices frequently. While this won’t protect your system, this practice can help you recover should the worst happen.