Mathematical Model of Information Security’s Threat Agent

To provide information security in automated control systems, the construction of an effective system of information security, it was not enough to identify channels of information leakage, to analyze the possible threats, the consequences of their implementation and estimate the losses. It is necessary to imagine an offender even better. An offender model is one of the most important components of a possible scenario for unlawful actions on access to information. The existence of such a model of a security breach, which is constantly corrected on the basis of obtaining new knowledge about the possibilities of the offender and changes in the security system, based on an analysis of the causes of violations, will allow themselves to affect these reasons, as well as more precisely define the requirements for the information security system from this type of violations. Correctly constructed model of the violator of information security, (adequate to reality), which reflects his practical and theoretical capabilities, a priori knowledge, time and place of action, etc. characteristics are an important part of a successful risk analysis and the definition of requirements for the composition and characteristics of the protection system. The difficulties of mathematical modeling in the study of information confrontation, which are conditioned, on the one hand, by the uncertainty of the opponent's actions, and on the other, the complexity of creating a conditional image, which in the largest degree corresponds to the branched protective structure, is considered in the paper. When creating a mathematical model one of the main tasks is to determine the parameters and characteristics that form the target function. The consideration of this task is devoted to this work. A model is considered in which the target function determines the proportion of information lost during an attack and is expressed through the dynamic vulnerability of the system, which depends on the ratio of attacks and protection resources, as well as on the likelihood of the implementation of such a relationship. The form of these dependencies is considered. The vulnerability is expressed by the fractional-power function in which the degree of power is determined by the nature of the information system and its structure. The density of probability of allocating an attack of resources with a given number of defense resources is given by a two-parameter distribution law. By selecting the indicators in both dependencies, it is possible to reach their maximum approximation to the statistical curves and eventually to form an explicit form of the target function.