A Parser for Deep Packet Inspection of IEC-104: A Practical Solution for Industrial Applications

We present a practical solution for deep packet inspection for IEC-104 SCADA traffic, which can be used in monitoring approaches to ensure the dependable operation of critical systems. We re-implement an outdated parser and extend it to also parse the content of individual IEC-104 packets and to extract information relevant for monitoring and securing the physical processes being controlled. The deep packet inspection framework Spicy was used for the implementation, which allows for easy extensibility in the future. To illustrate the feasibility of the proposed solution, the throughput obtained when using the parser in combination with the monitoring tool Zeek has been evaluated for traces of different lengths. The traces have been captured in an operating electrical distribution field station with a single RTU.