Shutting down a plant to install a security patch is no small matter. It can be both disruptive and costly. "Plant managers don't like to shut down work stations. A shutdown for an hour can cost a million dollars," said Neitzel. "They do not enjoy putting patches." Yet IT insists the patches are necessary to protect against known threats. So the patches go on, but only when downtime can be scheduled.
What's the threat?
Threats to plant networks come in a variety of forms. Some are as simple and common as an Internet worm. Others can be disgruntled ex-employees. "Threats are a big topic. You can limit it to two things: malware through a network interface, or hacking on the Internet," noted Neitzel. Preventing intrusion can be a matter of knowing who can get onto the automation system. "We close the window to keep people from connecting devices. We use a private network. Only if you know you're going to talk with us are you configured to connect," Neitzel said. He notes that if the device is not configured, it cannot find the system at all.
Security breaches can arise from simple, daily activities. "If someone says they need to recharge their iPhone and they use an USB port, an infected file can get to the network," said Neitzel. "We guard against that by disabling the USB ports. The customer can unlock them, but they have to be aware of the security risk. It's the same with CDs and DVDs."
Sesh Marellapudi, business segment head for industrial security at Siemens, agrees there is a wide assortment of threats. "They come in three categories: major, medium, and minor. Because there are so many, you never can have a single silver bullet to solve this problem," Marellapudi told Design News. "The threats are based on how the network is set up. Mobile devices are absolutely a threat. Tablets or iPhones, even USB sticks." Another risk from mobile devices is the ease with which they can grab data. "They can tap into plant data and upload it. Once someone has the access, you have a wide open hole unless everyone in the plant is properly authorized."
Security certification may help in network security. There is a movement in the control industry to define true network security practices. Neitzel is leading Emerson's effort to gain WIB Certification. The certification is the brainchild of The International Instrument Users Association (WIB) in The Netherlands. The organization provides process instrumentation evaluation and assessment services for its 25-plus end-user members. WIB is a purchasing specification driven out of Scandinavia that is being promulgated into IEEE and ISA standards. It requires demonstrated continuous improvement in practices to keep plant automaton systems secure from unwanted intrusion.