Antivirus software protects computers in many different ways. For starters, most antiviruses offer more than just "virus" protection. They protect computers from all different kinds of malware, like spyware, rootkits, phishing, and ransomware. For this reason, antiviruses are frequently interchangeably referred to as "anti-malware" programs. There are a few different ways that antiviruses protect against malware, but the most common way is through a regular scan of all the data and files on a computer's hard disk. In an antivirus scan, the software will look through every file on a computer, and it will compare each computer file's genetic makeup with the genetic makeup of already-known viruses. If a file has the same genetic makeup as a known piece of malware, it will be flagged as a problem. This is known as signature-based detection, and it is only effective when a malware file has been previously identified and shared with the community of malware researchers who maintain the malware database. Another typical kind of malware detection is through behavior analysis. This is when the antivirus software identifies an abnormal behavior in a computer file or program, causing the antivirus to flag that issue and assess whether or not the abnormality has been caused by malware or by something else.