Existing Building Automation Systems (BASs) and Building Automation Networks (BANs) have been shown to have serious cybersecurity problems. Due to the safety-critical and interconnected nature of building subsystems, local and network access control needs to be finer grained, taking into consideration the varying criticality of applications running on heterogeneous devices. In this paper, we present a secure communication framework for BASs that 1) enforces rich access control policy for operating system services and objects, leveraging a microkernel-based architecture; 2) supports fine-grained network access control on a per-process basis; 3) unifies the security control of inter-device and intra-device communication using proxy processes; 4) tunnels legacy insecure communication protocols (e.g., BACnet) through a secure channel, such as SSL, in a manner transparent to legacy applications. We implemented the framework on seL4, a formally verified microkernel. We conducted extensive experiments and analysis to compare the performance and effectiveness of our communication systems against a traditional Linux-based implementation of the same control scenario. Our experiments show that the communication performance of our system is faster or comparable to the Linux-based architecture in embedded systems.

Approved for public release, distribution is unlimited / Configuration Management (CM) plays a vital role in the development of trusted computing systems. The Common Criteria (CC) provides a framework for performing Information Technology (IT) security evaluations of these systems and further emphasizes CM's role in the development and evaluation process by specifying a minimum set of CM qualities for each Evaluated Assurance Level (EAL). As an evaluation guide, the Common Methodology for Information Technology Security Evaluation, Part 2: Evaluation Methodology (CEM), recommends a set of minimum CM guidelines which can be used by evaluators in the performance of a CM evaluation at the lower Evaluated Assurance Levels. Evaluators and developers will quickly note the CEM's lack of recommended CM guidelines at the higher assurance levels. Thorough study of the listed references supports the hypothesis for this work: Configuration Management guidelines are useful in the evaluation of trusted computing systems. As an assurance mechanism, complete CM guidance helps users of high assurance products obtain a degree of confidence the system security requirements operate as intended and do not contain clandestine code. Complete CM guidance provides evaluators with a "completed assurance scale" and ensures only authorized changes were made to the TOE during development. Useful CM guidelines at the higher assurance levels (EAL5, 6, and 7) will help developers and evaluators ensure products meet the minimum requirements needed for high assurance systems. / Lieutenant, United States Navy