What Is Antivirus and How Does It Work?
Antivirus is a program that prevents, detects and removes viruses and other malware (malicious software) from computers and mobile devices. It typically scans data — web pages, files, software, apps — traveling to your devices over the Internet or your local network for threats and flags any suspicious behavior to block attacks before they can cause harm.
Antivirus relies on a database of known infections to identify malware and prevent them from wreaking havoc. Because new infections are constantly created by hackers, antivirus programs refresh their infection databases regularly. The best antivirus programs also use technology that spots new threats based on their sketchy characteristics and demands, rather than simply looking for the malware signatures they’re known to contain.
When a virus infects your computer, it starts by finding other connected devices on the same local network, then identifying them and transferring itself to those devices. Most antivirus programs automatically scan for viruses, and if they find one, they quarantine it or delete it to stop it from spreading to other devices on your network.
It’s important to understand that most antivirus is reactive, not proactive. That means that once a virus is identified, the malware protection software will typically be updated in its database and can then automatically protect your device from those specific viruses. However, that also means that your antivirus program will erroneously flag legitimate files and programs as dangerous on occasion. For that reason, the best antivirus programs are typically paired with other online protection tools to provide a more comprehensive set of defenses.