Abstract
The results of studies aimed at further development of methods and algorithms for detection of cyber threats and the most common classes of anomalies and cyber attacks in critical information systems (CIS) are presented. First developed a method for intelligent recognition of threats based on the discrete procedures using the apparatus of logic functions and fuzzy sets, allowing you to create effective analysis, hardware and software solutions of the system of information protection CIS. First developed a model for making a decision rule proposed discrete procedures, which enables detection of threats, with a minimum number of errors. It is proved that the proposed approach allows solving complex problems of the CIS cyber defense control and can be used in the development of software solutions for cyber defense systems.