Maintained contact switch A switch designed for applications requiring sustained contacts but with provision for resting.
Mode of operation The specified operation condition of a switch, lock, door system, and so forth.
Momentary duty lock An electric lock equipped with a solenoid that is energized only momentarily.
Momentary switch A spring loaded contact that when pressed, closes two contacts. When pressure is removed the contacts open.
Motherboard A master printed circuit board used to interface the activities of individual printed circuit boards and the devices being controlled monitored. The motherboard is usually located on the back of a control panel assembly; individual printed circuit boards plug into it.
MAC Address : A physical address; a numeric value that uniquely identifies that network device from every other device on the planet.
Malicious Code : Software (e.g., Trojan horse) that appears to perform a useful or desirable function, but actually gains unauthorized access to system resources or tricks a user into executing other malicious logic.
Malware : A generic term for a number of different types of malicious code.
Mandatory Access Control (MAC) : Mandatory Access Control controls is where the system controls access to resources based on classification levels assigned to both the objects and the users. These controls cannot be changed by anyone.
Masquerade Attack : A type of attack in which one system entity illegitimately poses as (assumes the identity of) another entity.
md5 : A one way cryptographic hash function. Also see "hash functions" and "sha1"
Measures of Effectiveness (MOE): Measures of Effectiveness is a probability model based on engineering concepts that allows one to approximate the impact a give action will have on an environment. In Information warfare it is the ability to attack or defend within an Internet environment.
Monoculture : Monoculture is the case where a large number of users run the same software, and are vulnerable to the same attacks.
Morris Worm : A worm program written by Robert T. Morris, Jr. that flooded the ARPANET in November, 1988, causing problems for thousands of hosts.
Multi-Cast : Broadcasting from one host to a given set of hosts.
Multi-Homed : You are "multi-homed" if your network is directly connected to two or more ISP's.
Multiplexing : To combine multiple signals from possibly disparate sources, in order to transmit them over a single path.