The work is devoted to the problems of protecting the document management system of public administration bodies. The aim of the work is to build a simulation model of the implementation of a targeted computer attack, taking into account the simultaneous (occurring with a slight delay) response of the security tools of the document management system. For modeling, it is proposed to use the apparatus of Petri-Markov networks, combining the representation of the change of states of the attacked system in the form of Markov (semi-Markov) processes and the expressive capabilities of Petri nets to describe the interaction of processes. The constructed model reflects both the specifics of attacks with increased user privileges, and the features of document processing processes, as well as the mechanisms used to counteract unauthorized access. Computational experiments conducted using the constructed simulation model allow us to assess possible risks and make a decision on choosing the most effective system of protection against the considered type of attacks.

Keywords: electronic document management system, computer attack, simulation modeling, Petri-Markov network