Antivirus is software that is designed to detect, protect against, and remove malware on a computer or mobile device. Originally, it was created to protect against computer viruses, but now it's more of a general term to describe software that uses a combination of advanced technologies to protect against a variety of threats, including ransomware, spyware, and even never-before-seen zero day attacks. Early antivirus programs would compare software file signatures against a list of known viruses to see if they matched, and if so, block them. Today, cybersecurity companies like Malwarebytes employ several different methods to detect, block, or remove malware from a device.