Antivirus software protects computers from various types of malware, including viruses, trojans, worms, ransomware, and spyware. It operates by scanning files for known signatures of malware, monitoring the behavior of applications in real-time, and protecting against different vectors of attacks such as downloaded files, emails, and websites. Most antivirus solutions include features such as scheduled scans, automatic updates of virus definitions, and customizable settings for malware detection and response. Leading antivirus solutions also offer additional features such as firewalls and parental controls to enhance overall security.