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OPC considerations for network security

Oct. 11, 2005
It seems that whenever IT meets real-time control systems, trouble usually erupts, but this article shows that while industrial cyber security is complex, there are ways to keep your plant assets protected.
By Donovan Tindill, BAIST-NM, CETCYBER SECURITY means the confidentiality, integrity, and availability of computers, applications, and digital-based assets. In most organizations, this is the responsibility of the corporate IT group. Unfortunately, whenever IT meets real-time control systems, trouble erupts. So when IT implements different Windows, domains and firewalls, the first casualty is typically DCOM communication and, consequently, OPC traffic. It is an accepted fact that Microsoft Windows is the most prevalent desktop operating system in the world today, in homes, businesses, and industrial facilities. Thus, Windows has become a popular target of malicious network attacks. This is echoed in the fact that hackers constantly develop new worms and viruses that attempt to penetrate every network. These malicious applications are so contagious that the introduction of an infected laptop to an otherwise uncontaminated network can bring an enterprise down to its knees in minutes. It is for this reason that IT departments are concerned with cyber security. Their objective is to protect the users as well as all the connected devices. Unfortunately, IT departments rarely understand the operational needs of the production side of the business, so communication and compatibility problems quickly surface. One of the first casualties is DCOM (Distributed Component Object Model). Microsoft developed DCOM to provide an easy-to-use communication infrastructure for remote Windows applications and computers to work together. DCOM enables developers to reuse Microsoft’s methods and procedures in their own applications. This accelerates application development and increases reliability. It is for this reason that the OPC Foundation selected DCOM as the basic building block for OPC communication. DCOM comes from the IT side of the world. It is easy for programmers to use, but this ease comes at a price. DCOM requires many ports for finding other hosts, resolving names, requesting services, authentication, sending data, and more. If these ports are not available, DCOM will automatically search for others. Of course, any port and service used by DCOM is a target to cyber attacks (viruses and worms). So when DCOM security is compromised, all applications are affected including OPC applications. The recent Blaster and Sasser viruses attacked the same components that OPC relies upon. Anyone using OPC may be vulnerable to both of these viruses and more in the future. Cyber security is necessary for process control networks if they intend to integrate with business networks. Again, due to the pervasive nature of Windows and DCOM, when the IT department locks down communication, many applications, including OPC applications are immediately and frequently terminally affected. The good news is that if plant and business systems are configured and maintained correctly, network security and OPC can coexist nicely.ENTERPRISE NETWORK ARCHITECTURE

Addressing cyber security between plant production and business systems is a complex task that most IT and automation groups are hesitant to undertake. IT may not be familiar with complex industrial systems and any errors can adversely affect production. From the perspective of industrial automation, challenged with IT security they would rather just run autonomously and let a communication gap remain between these systems. Industrial cyber security at a minimum requires the focus areas listed felow:

Security Focus Areas

  • Filtering & Access Control
  • Written Best-Practices & Policies
  • Anti-Virus
  • Restoration Procedures
  • Data Backup Strategies
  • Incident Management Procedure
  • Active Monitoring & Detection
  • Continual Training & Awareness
  • Patch Management
  • 3rd-Party Verification

The short list above is an introduction; there are many more elements to consider. In general, the two focus areas are technology and people; and it does not matter which is managed first. The most important thing to remember is that existing corporate IT policies must empathize with the requirements of real-time control systems, many rules will have to change accordingly. Network and cyber security should be a priority making firewalls a necessity, which creates many new challenges for DCOM. Because DCOM requires so many ports to operate, it is very unfriendly to firewalls. Therefore, DCOM is frequently shut out of communication across different networks or left wide open for worm infection.


Fortunately, innovative solutions are already available. For instance, OPC can make use of tunneling technology to work across different systems and firewalls. Similar in concept to a VPN (Virtual Private Network) and PPTP (Point-to-Point Tunneling Protocol), OPC tunneling encloses the data payload inside another protocol. From the outside the tunnel, it looks like a stream of data. However, inside that stream is the all-important production data. Tunneling technology can also make use of port restriction, user authentication, and data-stream encryption to overcome most of IT’s security issues.

Network and cyber security are very important to industrial systems because they can affect the production of the control system. A complex task requires the aid of experts with field experience. They can recommend solutions for each of the security focus areas such as OPC tunneling for firewalls. It is important to begin addressing security risks as soon as possible, before they affect production.

  About the Author
Donovan Tindill, BAIST-NM, CET, Technical Lead of Network Services Group, Matrikon, helps clients in the industrial sectors by consulting at the plant level. He has personally audited industrial facilities, designed plant information systems and sought for consulting advice within plant IT security, reliability and performance.

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