The detection of computer attacks based on the functional approach

A brief summary of existing countermeasure methods and detection of computer attacks on information systems are stated. It is suggested that in the majority of defense systems the solution of the problem comes not to detection of computer attacks but simply to detection of its consequences while adaptability to unknown attacks in the majority of existing detection systems is missing. The mathematical model of computer attack detection based on the functional approach is proposed. The use of the functional approach presupposes the full set construction of secure conditions of an informational system and its further detection of computer attacks signs.