Definition: The word "scan" has several meanings as it relates to information security. One meaning relates to a command that causes anti-virus software installed on a computer to examine the files on a computer. Another definition of the word "scan" relates to a technique that crackers use to determine if any “ports” are open to an intrusion. Another variant of the word is used to describe what a tool like Netmap does to examine an entire network infrastructure. Simply, the ports on a computer are checked by another computer to learn if a connection can be made. The practice is known as port scanning.
Its Relevance: Part of an organization’s vulnerability assessment must be to examine all possible intrusion points. This functionality is included in most anti-virus software. Both automated and manual sweeps of the system can be structured. An organization’s official policies must include and consistently apply assessments of its system's vulnerabilities.