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Nak Attack

Negative acknowledgment attack—a penetration technique, that capitalizes on a potential weakness in an operating system that does not handle asynchronous interrupts properly and, thus, leaves the system in an unprotected state during such interrupts.

National Computer Security Center (NCSC)

Originally named the DoD Computer Security Center, the NCSC became responsible with the signing of NSDD-145 for encouraging the widespread availability of trusted computer systems throughout the federal government. (AF9K_JBC.TXT) (NCSC-WA-001-85) (NCSC).

National Information Infrastructure (NII)

The nationwide interconnection of communications networks, computers, databases, and consumer electronics that make vast amounts of information available to users. The NII encompasses a wide range of equipment, including cameras, scanners, keyboards, fax machines, computers, switches, compact disks, video and audio tape, cable, wire, satellites, fiber-optic transmission lines, networks of all types, monitors, printers, and much more. The friendly and adversary personnel who make decisions and handle the transmitted information constitute a critical component of the NII (pending approval in JP 1-02).

NCSC

See National Computer Security Center (NCSC).

Network

Two or more machines interconnected for communications.

Network-Based

Network traffic data along with audit data from hosts; used to detect intrusions.

Network-Level Firewall

A firewall in which traffic is examined at the network protocol (IP) packet level.

Network Security

Protection of networks and their services from unauthorized modification, destruction, or disclosure, and provision of assurance that the network performs its critical functions correctly and there are no harmful sideeffects. Network security includes providing for data integrity.

Network Security Officer

Individual formally appointed by a designated approving authority to ensure that the provisions of all applicable directives are implemented throughout the life cycle of an AIS network.

Network Weaving

Another name for Leapfrogging.

Nondiscretionary Security

The aspect of DOD security policy that restricts access on the basis of security levels. A security level is composed of a read level and a category set restriction. For read access to an item of information, a user must have a clearance level greater then or equal to the classification of the information and also have a category clearance, which includes all of the access categories specified for the information.

Non-Repudiation

Method by which the sender of data is provided with proof of delivery and the recipient is assured of the sender's identity, so that neither can later deny having processed the data.