The current state of development of information and telecommunication systems is impressive with its pace of implementation, scope and variety of technologies. Introduction of IP-telephony in various spheres of human activity allows ordinary people to simplify their lives, implement the main aspects for business, such as: increasing sales, improving employee efficiency, improving customer service quality, automating work processes, presenting the necessary information for management, etc. This technology (IP-telephony) has become a vivid symbiosis of classical telephony and the Internet, combining all the most important functions of these technologies. However, using IP telephony is important to ensure the necessary level of cybersecurity, since failure to implement this aspect can lead to significant financial and image losses, so the development and research of new effective methods for improving the cyber security of IP-telephony is an urgent task. Therefore, the purpose of this work is to build a data model for improving the cyber security IP-PBX. To achieve the goal, we will create a variety of types of IP-PBX vulnerabilities, a set of steps to implement cyberattack on the IP-PBX and a set of actions to improve the cyber security of the IP-PBX, which will identify possible types of vulnerabilities for the IP-PBX, investigate the sequence of steps to implement cyberattacks on IP-PBX and after performing preventive actions to improve the level of cybersecurity IP-PBX. After setting up an IP telephony server, following the example presented in the article, successful implementation of a cyberattack requires a very high level of intruder qualification of hacker and significant logistical costs. The developed model will be useful, first of all, for system administrators, as well as for information security specialists in the response teams for cyber incidents such as Computer Emergency Response Team / Computer Security Incident Response Team, which are responsible for the security of information and telecommunication systems within enterprises and organizations.