You Can’t Protect What You Don’t Understand: Characterizing an Operational Gas SCADA Network

Natural gas distribution networks are part of a nation’s critical infrastructure, ensuring gas delivery to households and industries (e.g., power plants) with the correct chemical composition and the right conditions of pressure and temperature. Gas distribution is monitored and controlled by a Supervisory Control and Data Acquisition (SCADA) network, which provides centralized monitoring and control over the physical process.In this paper, we conduct the first openly available network measurement study of the SCADA network of an operational large-scale natural gas distribution network. With a total of 154 remote substations communicating through the SCADA system with a Control Room and over 98 days of observation, this is, to the best of our knowledge, the most extensive dataset of this kind analyzed to date.By combining the information obtained from engineering and IEC 104 network traffic, we reconstruct the gas distribution system’s layout, including the type and purpose of the substations and the physical properties of the gas that enters the SCADA system. Our analysis shows that it is possible to extract this information, essential for security monitoring, purely from the raw network traffic and without background knowledge provided by the control system engineers. We also note that configuration changes in SCADA environments, although probably less frequent than in IT environments, are not as rare and exceptional as the research community assumed.