Cyber risk management for critical infrastructure is a current research topic due to the actuality of cyber threats in this domain. The number of attributes and dimensions that have to be taken into account require computer assisted decision making, to improve the efficiency and resources spent for this process. We proposed a model to evaluate the cyber security maturity in critical infrastructures [1], which was built with the scope of estimating the efficiency of a decision support system to be used for this task [2]. In this paper we present an application proof of concept for operationalizing this model in large organizations. We implemented the basic functionality for assessing the cyber security maturity based on the existing knowledge from the proposed model. The application is expandable and can be integrated and adjusted to the need of any organizations.