System Security

Security engineering is concerned with building systems that remain secure despite malice or error. Security engineering focuses on the tools, processes, and methods needed to design and implement complete systems that proactively and reactively mitigate vulnerabilities. Security engineering is a primary discipline used to achieve system assurance.

System Assurance

NATO AEP-67 (Edition 1), Engineering for System Assurance in NATO Programmes, defines system assurance as:

…the justified confidence that the system functions as intended and is free of exploitable vulnerabilities, either intentionally or unintentionally designed or inserted as part of the system at any time during the life cycle... This confidence is achieved by system assurance activities, which include a planned, systematic set of multi-disciplinary activities to achieve the acceptable measures of system assurance and manage the risk of exploitable vulnerabilities. (NATO February 2010, p. 1)

The NATO document is organized based on the life cycle processes in ISO/IEC 15288:2008 and provides process and technology guidance to improve system assurance.

Software Assurance

Since most modern systems derive a good portion of their functionality from software, software assurance becomes a primary consideration in systems assurance. CNSS (2010) defines software assurance as:

Level of confidence that software is free from vulnerabilities, either intentionally designed into the software or accidentally inserted at anytime during its lifecycle and that the software functions in the intended manner. (CNSS 2010, p. 69)

Goertzel, et. al (2008) point out:

The reason software assurance matters is that so many business activities and critical functions—from national defense to banking to healthcare to telecommunications to aviation to control of hazardous materials—depend on the on the correct, predictable operation of software. (Goertzel, et al. October 2008, p. 8)

Multidisciplinary Reach

This is not to say that hardware and the supply chain itself are not also concerns of security engineering. In fact, security engineering incorporates a number of cross-disciplinary skills, including cryptography, computer security, tamper-resistant hardware, applied psychology, supply chain management, and law. Security requirements differ greatly from one system to the next. System security often has many layers built on user authentication, transaction accountability, message secrecy, and fault tolerance. The challenges are protecting the right items rather than the wrong items and protecting the right items but not in the wrong way.

Robust Security Design

Robust security design explicitly rather than implicitly defines the protection goals. The Certified Information Systems Security Professional (CISSP) Common Body of Knowledge (CBK) partitions robust security into ten domains (Tipton 2006):

• Information security governance and risk management addresses the framework, principles, policies, and standards that establish the criteria and then assess the effectiveness of information protection. Security risk management contains governance issues, organizational behavior, ethics, and security awareness training.

• Access control is the procedures and mechanisms that enable system administrators to allow or restrict operation and content of a system. Access control policies determine what processes, resources, and operations users can invoke.

• Cryptography is the principles and methods of disguising information to ensure its integrity, confidentiality, and authenticity during communications and while in storage. Type I devices are certified by NSA for classified information processing. Type 2 devices are certified by NSA for proprietary information processing. Type 3 devices are certified by NSA for general information processing. Type 4 devices are produced by industry or other nations without any formal certification.

• Physical (environmental) security addresses the actual environment configuration, security procedures, countermeasures, and recovery strategies to protect the equipment and its location. These measures include separate processing facilities, restricted access into those facilities, and sweeps to detect eavesdropping devices.

• Security architecture and design contains the concepts, processes, principles, and standards used to define, design, and implement secure applications, operating systems, networks, and equipment. The security architecture must integrate various levels of confidentiality, integrity, and availability to ensure effective operations and adherence to governance.

• Business continuity and disaster recovery planning are the preparations and practices which ensure business survival given events, natural or man-made, which cause a major disruption in normal business operations. Processes and specific action plans must be selected to prudently protect business processes and to ensure timely restoration.

• Telecommunications and network security are the transmission methods and security measures used to provide integrity, availability, and confidentiality of data during transfer over private and public communication networks.

• Application development security is the controls applied to application software in a centralized or distributed environment. Application software includes tools, operating systems, data warehouses, and knowledge systems.

• Operations security is focused on providing system availability for end users while protecting data processing resources both in centralized data processing centers and in distributed client / server environments.

• Legal, regulations, investigations, and compliance issues include the investigative measures to determine if an incident has occurred and the processes for responding to such incidents.

Given the variety of security needs and various domains that contribute to system security, a commonly applied architecture and design approach is known as “defense in depth.” This approach implements multiple layers of defense and countermeasures, making maximum use of certified equipment in each layer to facilitate system accreditation.

A good web-based resource for System and Software Assurance is the U.S. Department of Homeland Security’s Build Security In web site (DHS 2010). The site provides resources for best practices, knowledge, and tools for engineering secure systems.

References

Citations

CNSS. 2010. National information assurance glossary,” committee on national security systems instruction (CNSSI) no. 4009.

DHS. Build security in [home page]. in U.S. Department of Homeland Security (DHS) [database online]. Washington, DC, 2010. Available from https://buildsecurityin.us-cert.gov (accessed 2010).

Goertzel, K., T. Winograd, and et al. October 2008. Enhancing the development life cycle to produce secure software: A reference guidebook on software assurance. Washington, D.C.: Data and Analysis Center for Software (DACS)/U.S. Department of Homeland Security (DHS).

NATO. February 2010. Engineering for system assurance in NATO programs. Washington, DC: NATO Standardization Agency, DoD 5220.22M-NISPOM-NATO-AEP-67.

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Signatures

--Bkcase 19:09, 22 August 2011 (UTC) (on behalf of Dick Fairley)

--Asquires 18:34, 31 August 2011 (UTC)red link to Software Assurance glossary item.