The task of analyzing and selecting the best scenario of a cyberattack on information and communication system is considered as a component of the task of analyzing systems security. A method and corresponding algorithm for finding the best scenario of an attack on information and communication system using a logical and probabilistic model is proposed. The model describes the development of adverse events that arise in the information and communication system from the implementation of possible attacks on the security system from cyberspace. Analysis of cyber attack scenarios allows predicting the development of possible adverse cyber security events from the implementation of multiple threats to the system. The developed method and corresponding algorithm for analyzing attack scenarios can be used to analyze the security of information and communication systems, as well as in automation systems for designing information security systems or designing attacks on such systems.