Industrial Automatic Control Systems and Controllers Annotation << Back Models of DDoS Attacks and Research of Information System Security against this Type of Threats A.Yu. Ermakova The article is devoted to the construction of theoretical and experimental models of DDoS attacks on computer systems. The purpose of these attacks is to generate a large number of requests to the server of the information system for a limited period of time, leading to blocking its operation. In the theoretical attack model, it is assumed that requests to the server are received independently of each other with the same probability. The time interval and the maximum number of requests that the server can process during this interval is fixed, and the event consisting in the successful implementation of a DDoS attack for a period of time is determined. The Attack is considered to be successfully implemented if there is a time interval during time T, at which more than one request will be made. The article shows that the problem of calculating the probability of this event is reduced to the problem of the distribution of the maximum of the sliding summation process (partial sums Erdesh-Renyi) and presents the results of the study of the asymptotic behavior of the distribution function of the statistics. To build an experimental model of DDoS attacks, on the basis of real Kaspersky Lab data on the intensity of this type of attacks, the author constructed a continuous predictive function that allows to build predictive intensity values for a given time interval. By further entering the values of losses from this type of attacks, it is possible to obtain estimates for the time of safe operation of the information system against which these attacks are implemented. Keywords: computer attacks; the requests to the server; the process of moving summation; predictive model. DOI: 10.25791/asu.12.2019.1074 Contacts: - Pp. 54-59.