The article defines the main tasks and features of corporate information networks and analyzes the specifics of the corporate network implemented in a medical center. The proposed data protection system at the enterprise is developed on the basis of the Bella-La Padula model since the key provisions of this model are the assignment of special security levels to all participants in the protected data processing process and to the documents in which it is contained. The specified security levels are arranged using the established dominance relationship, and the access control is carried out depending on the security levels of the interacting parties, which allows the application of technical solutions of the Active Directory service. One of the elements to ensure data protection is the use of a Shadow Copy of data according to the appropriate schedule. An important component of ensuring data protection is the individual process of setting up group policies and checking replication with other servers running the Active Directory directory services of the medical center. As a result of the implementation of elements of the company's data protection system, it was possible to significantly increase the level of protection and set up a backup server, on which appropriate folders were created, to which backup copies would be made according to the schedule. This function makes it possible to save the history of changes in any file for a certain period. The proposed elements of the security system can be used to analyze the security system, control access, ensure data integrity, etc. The Active Directory directory services were implemented in the medical center, and data replication to a backup server was configured. Taking into account the specifics of the enterprise, namely the medical center, the implemented elements of the data protection system ensure the delimitation of access levels, implement protection profiles and secure the personal data of patients.