Software separation in measuring instruments through security concepts and separation kernels

Abstract

In the age of the Internet of Things and Industry 4.0, more and more embedded systems are connected through open networks, which also concerns measuring instruments under legal control (e.g. smart meters). Therefore, cyber-security for measuring instruments is becoming increasingly important. In this paper, possibilities to design secure measuring software running on general-purpose operating systems are analyzed according to legal requirements set up by European Directives, e.g., the Measuring Instruments Directive (2014/32/EU), which define the mandatory security level. Technical interpretations for the security concepts described in this paper are derived from these legal requirements with the aim to provide manufacturers the architectural guidance to construct systems which easily pass a conformity assessment at a Notified Body. In this paper security concepts, i.e., SELinux, AppArmor and Mandatory Integrity Control (MIC) are being described, which are based on Mandatory Access Control (MAC) strategies. Additionally, high-security methodologies and concepts, e.g., Multiple Independent Layers of Security (MILS) and security kernels, are highlighted. In the examples given, software separation, which enhances overall security, is achieved by using SELinux mechanisms in the modules (virtual machines) atop a separation kernel.