Instruments and Systems: Monitoring, Control, and Diagnostics Annotation << Back Problem of finding the negative external effects on the elements of network information systems that maximize the value of the damage is incomplete GROMOV Yu.Yu. MININ Yu.V. IVANOVA O.G. SAMKHARADZE T.G. MARTEMYANOV Yu.F. This paper is devoted to the choice of means of countering external influences set against negative external influences acting on the network information system so that the sustainability of the latter was the highest. This paper describes the formulation and algorithms for solving the two problems of finding the negative external effects on the elements of network information systems that maximize the value of the damage. Keywords: network information system, the negative external effects, the probability. Contacts: E-mail: gromovtambov@yandex.ru Pp. 25-30.