This paper deals with the questions of computer network, attacks, threats, network attacks, "Denial of Service", DoS-attacks, DDoS-attacks, DRDoS-attacks, mathematical model. The article presents an approach to detection of the distributed network attacks to refusal in service, the offered method increases efficiency of use of the calculated resource of a computer network at the big distributed network attacks to "Denial of Service". The paper proposes a mathematical model of compromised node and the number of all possible routes that can have an admission to access points, have done a comparative characteristics of attacks DoS / DDoS / DRDoS in computer network.

In practice the most part of connections of subjects of a wide area network uses the virtual connections as this method is the dynamic protection of network connection and won't use static key information. Therefore, the interaction without establishing a virtual channel is one of the possible reasons for the success of remote attacks such as DoS / DDoS. An abstract considers the mathematical model of system of protection of computer networks against attacks such as DoS/DDoS, allowing in practice to detect attacks such as DoS / DDoS. Grounded way to prevent attacks through the use of network reconfiguration procedures, it is difficult for practical implementation attacks such as DoS / DDoS. The algorithm to create new virtual data channels to ensure a minimum amount of traffic regardless of reconfiguring computer network. The article presents an approach to detection of the distributed network attacks to refusal in service, the offered method increases efficiency of use of the calculated resource of a computer network at the big distributed network attacks to "Denial of Service".

The article proposes an adaptive model for selection of strategies for cybersecurity financing of an informatization object with incomplete information on the financial resources of the attacking side. The case is considered when the financial resources of the protection side belong to some fuzzy set. The model is intended for the developed decision support system in the tasks of selection of rational variants for investing in information protection systems. The solution was obtained by using the tools of the theory of multi-step games with several terminal surfaces. The model is distinguished by the assumption that the protection side does not have complete information both about the financial strategies of the attacking side and about the state of its financial resources aimed at overcoming the boundaries of information protection. The assumption is made that the protection side has the opportunity to obtain additional information due to spending a part of its financial resources. The model was tested using a computational experiment, the results of which are also given in the article.