Industrial Ethernet security check

Security for an industrial Ethernet network has to thwart hacking, unauthorized access, and disruption caused by unwanted traffic in industrial control and automation environments, which can cause downtime, program failures, and health and safety problems. Phoenix Contact gives security tips.

09/01/2011


Security for an industrial Ethernet network is essential. What was once strictly an IT or “office network” issue has now become vital for plant managers and control engineers. Hacking, unauthorized access, and disruption caused by unwanted traffic in industrial control and automation environments can cause downtime, program failures, and health and safety problems. The Stuxnet worm is only one example of the challenges emerging as supervisory control and data acquisition (SCADA) and control systems receive more attention from the hacking and malware community.

Control network security lessonsImplementing proper security while designing a new install or doing an upgrade to your industrial network is easier, and more cost-effective, than trying to address it in a mature environment. There are emerging product lines in the industrial arena that provide both the security and “higher level” networking found in commercial equipment, while featuring rugged hardware that meets the demands of the industrial network.

A firewall is a big first step in securing an industrial network. Stateful firewalls have long been used in the IT world but are now available in industrial equipment. A firewall allows an engineer to block certain network traffic from getting onto the control network by inspecting characteristics such as source and destination IP address and protocol, for example, Modbus/TCP. Simple rules can be created on the firewall to allow “acceptable” traffic through and block unwanted or unnecessary traffic from getting on the network. Another means of providing security on the network is to implement a strategy of “defense in depth.” This principle provides layers of security, which helps increase the difficulty of breaching the network and also mitigates the scope of any damage done by confining the breach to a small, isolated area. Due to the modularity of this approach, it is very easy to add layers of defense and to incorporate new machines or cells as they come on-line.

Increasingly, industrial networks are linked to IT networks, and in some cases there is a shared responsibility of supporting the network. This makes interoperability with IT equipment and protocols vital. Standardization is heavily used and greatly sought after in the IT world, where it helps drive down support costs and learning curves, even at the occasional expense of innovation. So when interacting with the IT network, you should strive to use open and accepted protocols and standards such as Rapid Spanning Tree (RSTP) for redundancy, VLANs for network segmentation, and IPSec for secure remote communication.

- Dan Schaffer is with Phoenix Contact, product marketing - networking and security. Edited by Mark T. Hoske, CFE Media, Control Engineering, www.controleng.com.

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