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What Is Antivirus?

Anti-virus software is a utility that detects, prevents, and removes viruses, worms, and other malware from a computer. The best antivirus software will often include an auto-update feature that permits the program to download profiles of new viruses, enabling the system to check for new threats. Anti-virus tools are essential utilities for any computer. One AV tool may find a certain virus or worm while another can’t, or vice-versa.


These utilities are also known as anti-virus programs or vaccines.

Techopedia Explains Antivirus

Anti-virus tools search the hard drive and external media attached to a computer for viruses, malware, or worms. Broadly speaking, the two main approaches to virus detection are:

  • Dictionary Approach: The program checks a file and automatically refers to a dictionary or software database of known viruses. If there is a match, the file is deleted, quarantined, or repaired.
  • Suspicious Behavior Approach: The program monitors the behavior of all programs using heuristic analysis and flags any suspicious behavior. For example, a program might be flagged if it tries to change settings to the operating system or write to a certain directory.
  • Sandboxing: To evade detection, modern hackers sometimes encrypt virus signatures or parts of them, making it impossible for an antivirus to detect them using traditional methods. Sandboxing is an advanced form of behavioral analysis where suspicious programs are tested and permitted to run in a controlled environment before they’re allowed onto the full system. If the software doesn’t do anything suspicious, it’s allowed to run as normal.

How Does an Antivirus Work?

Antivirus products scan your system to find potential threats such as viruses, malware, spyware, and ransomware in order to detect and remove them.

Consumer anti-virus tools are typically able to:

  • Scan your system for threats
  • Quarantine or remove suspicious files
  • Scan downloads to prevent threats from accessing your system
  • Apply browsing protection, checking sites for signs of malicious behavior
  • Scan emails for suspicious links and attachments that may contain malware or be indicative of phishing activity

Leading antivirus providers have processed huge amounts of data using machine learning models to create powerful algorithms that can identify patterns and find viruses by analyzing their structure and behavior. After the antivirus has scanned your system, you have two options to tackle any threats found:

  • Quarantine — This means keeping malicious files and programs in a separate location. The threat remains on your device but cannot access other parts of the system, spread, or cause damage.
  • Removal — This is a more complete approach that deletes the infected files and the threat altogether, removing it from the system so it’s no longer a concern.

To provide comprehensive security coverage, antiviruses today are often packaged with firewalls, VPNs, data breach monitoring tools, password managers, parental controls, and identity theft protection features.

The Bottom Line – How Does Antivirus Software Work?

Anti-virus software uses a range of detection methods to find and eliminate threats on your device. These include signature-based detection, comparing suspicious files to malware databases, and behavior-based monitoring, whether on your device or in isolated sandbox environments.

Leading providers now have extensive databases of malicious software. This is augmented by machine-learning techniques that are able to detect unusual network activity and identify potential novel threats.

B2B and B2C anti-virus vendors today are able to provide an extensive range of cybersecurity tools that can provide multi-layered digital protection and offer assurance for their customers.


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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.