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Guest Editors' Introduction: Process Control System Security: Bootstrapping a Legacy

Charles C. Palmer, IBM Research
Ron Trellue, Trellue Consulting

Pages: pp. 22-23

Why all the fuss about process control system (PCS) security these days? Control systems, PCSs, industrial control systems, distributed control systems, and other similarly named systems control the processes that manage the components of our critical infrastructures, such as the electric power grid, factories and refineries, oil and gas pipelines, and water infrastructures. Operated and maintained by process control engineers, these traditionally dedicated, stand-alone control systems might only be able to be modernized or replaced every 10 years. The people using these systems, however, want to enjoy increased functionality that recent applications, email, and Web browsing offer—things they can easily get by connecting directly to the Internet. How can these critical real-time control systems continue to work uninterrupted when introduced to the wild and lawless world of the Internet? How are these legacy systems going to keep pace with the rapidly changing environment of modern information technology security? Can the IT security industry evolve its products to be effective on these real-time systems, where the emphasis is often on resiliency and availability first and confidentiality second?

In this special issue, our first article, "Security for Process Control Systems: An Overview," by Markus Brändle and Martin Naedele of ABB Corporate Reseach, sets the stage by introducing problems facing control system security today, describing current industry security practices and discussing challenges that remain. (ABB is one of the top international PCS vendors.) Problems include assessing and understanding the risks, integrating enterprise system technology and thinking with control system operations, and the need to develop and enforce a security policy. The authors explain why security isn't like safety and how control systems differ from the information technology environment of the office. The control system community relies on standards being developed by consensus through several industry groups and associations. The article briefly discusses standards being developed by the ISA SP99 standards committee and touches on the controversial topic of certification.

David M. Nicol, William H. Sanders, Sankalp Singh, and Mouna Seri from the University of Illinois at Urbana-Champaign in their article, "Usable Global Network Access Policy for PCS," address the need for system-wide access policy checking and enforcement software as one of the tools that should exist in a control system's security toolkit. Such a tool must be easy to use and function in the heterogeneous control system environment. The workings of the Access Policy Tool illustrate how automation might be able to help operators and system administrators better understand whether their access control mechanisms are actually enforcing the access control policy they desire.

In "Vulnerability Assessment for Critical Infrastructure Control Systems," Ray Parks of Sandia National Laboratories and Edmond Rogers of Ameren Services give practical advice on how to perform a security assessment based on the fairly recent North American Electric Reliability Corporation's (NERC's) Critical Infrastructure Protection standards. The authors detail a critical infrastructure protection cybervulnerability assessment process developed from years of experience with the control system community. The development of standards, recommended practices, and regulations is only as good as companies' ability to measure and document how they're doing in respect to those standards. Wouldn't it be nice to have security metrics that would immediately tell you whether you're secure enough? Through work by groups like NERC, the US National Institute of Standards (NIST), and these authors, progress is being made on defining and measuring security in these environments.

In our final article, Alysson Neves Bessani, Paulo Sousa, Miguel Correia, Nuno Ferreira Neves, and Paulo Veríssimo at the University of Lisbon look to the future by proposing a secure architecture for the next generation of control systems. "The Crutial Way of Critical Infrastructure Protection" describes a sophisticated approach to security using smart devices such as the Crutial Information Switch.


These articles describe only a few of the efforts now under way to improve PCS security. Awareness and education during the past few years has led to an eagerness in the PCS arena to focus on protecting these critical infrastructures from threats of a cyber nature. At the same time, concerns about disruptions to these systems, whether caused by natural disasters or humans, have become acute. We thank the authors of all the articles submitted for their hard work and the external reviewers for their efforts in helping us select and review these articles. Information on other research in the PCS security area can be found at

About the Authors

Ron Trellue is a consultant to the Institute for Information Infrastructure Protection (I3P), where he has been supporting its PCS security projects since August 2006. Prior to his retirement in 2006, he was the senior manager of the Information Assurance and Survivability Group and deputy director of the Information Systems Analysis Center at Sandia National Laboratories. Trellue has an MS in computer science and a BS in physics from New Mexico State University. Contact him at
Charles C. Palmer is CTO of security and privacy at IBM Research and the chair and director of research for the Institute for Information Infrastructure Protection ( His technical interests vary widely, including cybersecurity, security engineering and usable security, and privacy. Palmer has a PhD in computer science from Polytechnic University, New York. He is an ACM Distinguished Engineer and a member of the IEEE. Contact him at
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