The glossary below contains many of the terms you will find in common use throughout our website. Please refer to this list to find definitions of terms and answers to other Internet security-related questions.


A known weakness in an operating system or application that could be exploited by an attack. Vulnerabilities are discovered and reported by vulnerability scanning products.

A design, administrative, or implementation weakness or flaw in hardware, firmware, or software. If exploited, it could lead to an unacceptable impact in the form of unauthorized access to information or disruption of critical processing.