The article considers the issues of IoT systems and networks privacy. The complex researches on general system theory state of the art has been surveyed, as well as cybersecurity aspects of IoT technologies and models analyzed over the past decades with respect to the Industry 4.0 concept and industrial IoT architecture. A comprehensive decomposition formalism proposed on the base of M. Mesarowic system theory for presenting the complex cybersecurity object of study as a set of its parts. An original context-defined model of open systems interaction S-CDM has been constructed for cybersecurity issues study with the use of J. Neumann classification and A. Uemov system triad. The S-CDM model is shaped in 3-layer hierarchical graph. The first S-CDM layer displays the cybersecurity problem as a set of relations between the key players of information market - resources, clients and agents. The second S-CDM layer adds the network technologies impact on the relations between the key market-players. The third S-CDM layer includes a “degree of trust” factor into the key market-player relationships. The introduced context-defined model enables to reduce the overall problem complexity of the IoT cybersecurity study to a number of less complex and easy-handled partial tasks. As an example, a particular local version of the S-CDM model is considered in the form of six independent tasks for AI-aided methods of cybersecurity provision. The results of the work intend to contribute general system researches in the sphere of network system modelling and IoT privacy.