An Access Management System to Mitigate Operational Threats in SCADA System

One of the most dangerous insider threats in a supervisory control and data acquisition (SCADA) system is the operational threat. An operational threat occurs when an authorized operator misuses the permissions, and brings catastrophic damages by sending legitimate control commands. Providing too many permissions may backfire, when an operator wrongly or deliberately abuses the privileges. Therefore, an access management system is required to provide necessary permissions and prevent malicious usage. An operational threat on a critical infrastructure has the potential to cause large financial losses and irreparable damages at the national level. In this paper, we propose a new alarm-trust based access management system reducing the potential of operational threats in SCADA system. In the proposed system, the accessibility of a remote substation will be determined based on the operator trust and the criticality level of the substation. The trust value of the operator is calculated using the performance of the operator, periodically or in emergencies, when an anomaly is detected. The criticality level of the substation is computed using its properties. Our system is able to detect anomalies that may result from the operational threats. The simulation results in the SCADA power system of Iran show effectiveness of our system.