INSIGHTS | July 4, 2013

Why sanitize excessed equipment

My passion for cybersecurity centers on industrial controllers–PLCs, RTUs, and the other “field devices.” These devices are the interface between the integrator (e.g., HMI systems, historians, and databases) and the process (e.g., sensors and actuators). Researching this equipment can be costly because PLCs and RTUs cost thousands of dollars. Fortunately, I have an ally: surplus resellers that sell used equipment.

I have been buying used equipment for a few years now. Equipment often arrives to me literally ripped from a factory floor or even a substation. Each controller typically contains a wealth of information about its origin. I can often learn a lot about a company from a piece of used equipment. Even decades-old control equipment has a lot of memory and keeps a long record about the previous owner’s process. It is possible to learn the “secret recipe” with just a few hours of work at reverse engineering a controller to collect company names, control system network layout, and production history. Even engineers’ names and contact information is likely to be stored in a controller’s log file. For a bad guy, the data could be useful for all sorts of purposes: social engineering employees, insider trading of company stock, and possibly direct attacks to the corporate network.
I reach out to the origin of used equipment when I find these types of information. I help them wipe the equipment, and I point them to where the rest of the equipment is being sold in an attempt to recall it before the stored information ends up in the wrong hands. I am not the only one doing this kind of work. Recently, Billy Rios and Terry McCorkle revealed surplus equipment that they had purchased from a hospital. It had much of the same information about its origin.

These situations can be prevented by sanitizing the equipment before it’s released for disposal. Many equipment manufacturers should be able to provide instructions for this process. One option may be to send the controller back to the manufacturer to be sanitized and refurbished.
A way to provide another layer of protection against information disclosure is to have a robust and well-practiced Incident Response plan. Most places that I contact are great to work with and are receptive to the information.

Ignoring the issue, especially where a public utility is concerned, may be considered a violation. Set up an Incident Response program now and make sure that your process control engineers know to send equipment disposal issues through the IR group.


A great deal can be accomplished to keep a control system secure. With a little planning, proper equipment disposal is one of the cheapest things that can be done to keep proprietary process information safe.