The paper researches the usage of ARIS Express process modeling tool in creation of economically sustainable information security management system in seaport clusters. Basic concepts of information security in seaport cluster stakeholder’s organizations are detailed, and relations and interactions between organizations and their environment are researched. Portfolio approach to information security is being endorsed along with quantification of total levels of the risk and the resulting cost of information security. The authors identify two basic process paths of information security in seaport clusters: basic activities and supporting activities. Furthermore, main components of both are being researched in detail, along with their interactions that create a robust system of information security management in seaport clusters. Process flow of all activities is constructed by using business process model implementation of ARIS Express software