Scalable backend representation of security posture of IIoT systems

Abstract

The focus of this paper is the scalable modelling and database representation of cybersecurity postures as part of a framework for modelling of security artefacts. A cybersecurity posture describes the current state of protection of a system. During the lifecycle phases of a power plant or manufacturing facility this includes the semi-formal database representation of all components and subsystems of automation equipment, the controlled aggregates, the related sensors and the applied security controls. The type of database choice is discussed based on the need to serve as web backend server and scalable multi-user use. The frontend part of a comprehensive security artefacts modelling framework is not in the focus of this paper. One focus will be on the modelling related to network security artefacts as supporting assets. This will include all network devices and network endpoints with segregations between networks by physically unidirectional security gateways and firewalls. The primary assets (that are controlled or monitored) will be selected and can include pumps, pressurizers, valves, motors, circuit breakers and similar. The important part of the modelling is to be able to represent the potential attack vectors via supporting assets up to the primary assets that may potentially be destroyed or degraded by an attack. An important aspect of the data modeling is the security grading, as present in industrial environments, but not covered by the common IT security standards (like ISO/IEC 2700x). The current state of the art of tools and frameworks that cover a part of the intended data modelling will be outlined. The backend of a document based (e.g. MongoDB) database for modelling the relations will be presented in more detail. The backend semi-formal representation takes into account the semi-formal approach of structuring of the supporting assets, structuring of primary assets, linking between assets and association of Application Security Controls in the sense of ISO/IEC 27034-5 and ISO/IEC 27034-5-1 (for XML/JSON representation) to supporting assets.[ IS17] [IS18] A web framework will be used to interact with the backend data representation. Approaches to compare different revisions of a security posture will be outlined. This will help in planning and regularly monitoring the progress of a security posture, e.g. with regard to security audit preparations.