National Security System

Any information system (including any telecommunications system) used or operated by an agency or by a contractor of an agency, or other organization on behalf of an agency—(i) the function, operation, or use of which involves intelligence activities; involves cryptologic activities related to national security; involves command and control of military forces; involves equipment that is an integral part of a weapon or weapons system; or is critical to the direct fulfillment of military or intelligence missions (excluding a system that is to be used for routine administrative and business applications, for example, payroll, finance, logistics, and personnel management applications); or (ii) is protected at all times by procedures established for information that have been specifically authorized under criteria established by an Executive Order or an Act of Congress to be kept classified in the interest of national defense or foreign policy. [44 U.S.C., SEC. 3542]
SOURCE: FIPS 200; SP 800-37; SP 800-53; SP 800-53A; SP 800-60

Any information system (including any telecommunications system) used or operated by an agency or by a contractor of any agency, or other organization on behalf of an agency, the function, operation, or use of which: I. involves intelligence activities; II. involves cryptologic activities related to national security; III. Involves command and control of military forces; IV. involves equipment that is an integral part of a weapon or weapon system; or V. subject to subparagraph (B), is critical to the direct fulfillment of military or intelligence missions; or is protected at all times by procedures established for information that have been specifically authorized under criteria established by an Executive Order or an Act of Congress to be kept classified in the interest of national defense or foreign policy.

Subparagraph (B). Does not include a system that is to be used for routine administrative and business applications (including payroll, finance, logistics, and personnel management applications). (Title 44 U.S. Code Section 3542, Federal Information Security Management Act of 2002.)
SOURCE: CNSSI-4009