6 research outputs found

    Role based access control and authentication for SCADA field devices using a dual Bloom filter and challenge-response.

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    Supervisory control and data acquisition (SCADA) systems are networked control systems used in many critical infrastructure areas such as power water and transportation. Many of these systems continue to use legacy field devices that lack cyber security features. The field device security preprocessor is a bump-in-the-wire security solution of legacy field devices. This thesis describes the design and analysis of a dual Bloom filter structure for use in a field device security preprocessor. A dual Bloom filter is a variant of the traditional Bloom filter, that performs role based access checks in O(1) time. It is shown this structure, which can produce false authentications is shown to be acceptable for this security use thought analysis and penetration testing. Analysis and testing shows that in spite of false positives this structure can provide the required level of security, while maintaining the required level of performance on low cost hardware

    A prototype security hardened field device for SCADA systems.

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    This thesis describes the development of a prototype security hardened field device (such as a remote terminal unit) based on commodity hardware and implementing a previously developed security architecture. This security architecture has not been implemented in the past due to the difficulty of providing an operating system which meets the architecture\u27s isolation requirements. Recent developments in both hardware and software have made such an operating system possible, opening the door to the implementation and development of this new security architecture in physical devices attached to supervisory control and data acquisition (SCADA) systems. A prototype is developed using commodity hardware selected for similarity to existing industrial systems and making use of the new OKL4 operating system. Results of prototype development are promising, showing performance values which are adequate for a broad range for industrial applications

    Design Considerations for Building Credible Security Testbeds : A Systematic Study of Industrial Control System Use Cases

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    This paper presents a mapping framework for design factors and implementation process for building credible Industrial Control Systems (ICS) security testbeds. The resilience of ICSs has become a critical concern to operators and governments following widely publicised cyber security events. The inability to apply conventional Information Technology security practice to ICSs further compounds challenges in adequately securing critical systems. To overcome these challenges, and do so without impacting live environments, testbeds for the exploration, development and evaluation of security controls are widely used. However, how a testbed is designed and its attributes, can directly impact not only its viability but also its credibility as a whole. Through a combined systematic and thematic analysis and mapping of ICS security testbed design attributes, this paper suggests that the expertise of human experimenters, design objectives, the implementation approach, architectural coverage, core characteristics, and evaluation methods; are considerations that can help establish or enhance confidence, trustworthiness and acceptance; thus, credibility of ICS security testbeds

    Security hardened remote terminal units for SCADA networks.

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    Remote terminal units (RTUs) are perimeter supervisory control and data acquisition (SCADA) devices that measure and control actual physical devices. Cyber security was largely ignored in SCADA for many years, and the cyber security issues that now face SCADA and DCS, specifically RTU security, are investigated in this research. This dissertation presents a new role based access control model designed specifically for RTUs and process control. The model is developed around the process control specific data element called a point, and point operations. The model includes: assignment constraints that limit the RTU operations that a specific role can be assigned and activation constraints that allow a security administrator to specify conditions when specific RTU roles or RTU permissions cannot be used. RTU enforcement of the new access control model depends on, and is supported by, the protection provided by an RTU\u27s operating system. This dissertation investigates two approaches for using minimal kernels to reduce potential vulnerabilities in RTU protection enforcement and create a security hardened RTU capable of supporting the new RTU access control model. The first approach is to reduce a commercial OS kernel to only those components needed by the RTU, removing any known or unknown vulnerabilities contained in the eliminated code and significantly reducing the size of the kernel. The second approach proposes using a microkernel that supports partitioning as the basis for an RTU specific operating system which isolates network related RTU software, the RTU attack surface, from critical RTU operational software such as control algorithms and analog and digital input and output. In experimental analysis of a prototype hardened RTU connected to real SCADA hardware, a reduction of over 50% was obtained in reducing a 2.4 Linux kernel to run on actual RTU hardware. Functional testing demonstrated that different users were able to carryout assigned tasks with the limited set of permissions provided by the security hardened RTU and a series of simulated insider attacks were prevented by the RTU role based access control system. Analysis of communication times indicated response times would be acceptable for many SCADA and DCS application areas. Investigation of a partitioning microkernel for an RTU identified the L4 microkernel as an excellent candidate. Experimental evaluation of L4 on real hardware found the IPC overhead for simulated critical RTU operations protected by L4 partitioning to be sufficiently small to warrant continued investigation of the approach

    Design Considerations for Building Credible Security Testbeds: Perspectives from Industrial Control System Use Cases

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    This paper presents a mapping framework for design factors and an implementation process for building credible Industrial Control Systems (ICS) security testbeds. The security and resilience of ICSs has become a critical concern to operators and governments following widely publicised cyber security events. The inability to apply conventional Information Technology security practice to ICSs further compounds challenges in adequately securing critical systems. To overcome these challenges, and do so without impacting live environments, testbeds are widely used for the exploration, development, and evaluation of security controls. However, how a testbed is designed and its attributes, can directly impact not only its viability but also its credibility. Combining systematic and thematic analysis, and the mapping of identified ICS security testbed design attributes, we propose a novel relationship map of credibility-supporting design factors (and their associated attributes) and a process implementation flow structure for ICS security testbeds. The framework and implementation process highlight the significance of demonstrating some design factors such as user/experimenter expertise, clearly defined testbed design objectives, simulation implementation approach, covered architectural components, core structural and functional characteristics covered, and evaluations to enhance confidence, trustworthiness and acceptance of ICS security testbeds as credible. These can streamline testbed requirement definition, improve design consistency and quality while reducing implementation costs
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