The best approach for securing operational technology is to, first, examine OT's significant security challenges in a far more discriminating manner than the industry currently does. I propose that we use the time-tested threat analysis approach to patching OT systems that can't simply be patched the way IT systems are, for many reasons.
The first step in threat analysis would be to hold off taking any immediate action — patching, not patching, something else — until we validate if a system vulnerability actually exists and, if it does, how it can be exploited.
There are multiple factors to consider. For one, some systems that operate deep inside enterprises may indeed have vulnerabilities, but because the system is so isolated within the enterprise, the actual security risk is less than the risk of shutting the systems down for patching, assuming patches exist.
The calculus changes, of course, when evaluating systems that are exposed to the cloud or the Internet, where the security risk is obviously much greater. Threat analysis would identify which systems can probably go on operating without patches, and which need to be stopped for patching.
Threat analysis would also validate a vulnerability, but it is important to ask another question: If this vulnerability can be exploited by certain threats, is there a way to protect from those threats short of patching? For example, security experts could create a set of predetermined scripts within the network, or on the endpoint device itself, that would help identify the appropriate response to a number of different threats. These scripts would serve as an "if/then" template to formalize, automate, and accelerate responses to threats. The point is to think with more sophistication than a binary patch/don't patch decision.
Wanted: Better Patch Info
Software companies must support the development of threat analysis by telling customers more about the patches they release. Key pieces of information we'd like to see are how vulnerabilities can be exploited and possible ways to protect against them. This extra transparency would give customers more information to make decisions on the right security actions for affected systems. Security experts need to be confident a patch will, at the very least, maintain the same risk level that existed before a vulnerability was discovered.
Threat analysis must be extremely granular. If an enterprise has 100 devices running, each one requires its own threat analysis, which would include a comparison of vulnerabilities versus patch benefits, as well as a resulting menu of security options. The primary goal, of course, is to enhance security while at the same time maximizing OT uptime.
Clearly, threat analysis is more nuanced and multidimensional than go/no-go patching decisions. But it's a challenge the industry must solve to get from where we are to where we should be. Right now, following the process described above takes time, costs money, requires highly skilled professionals — and even then, it's not easy to do. However, if the vendor community agreed upon a set of standards on how it reports and addresses vulnerabilities, this entire process could be automated.
Some security approaches developed in IT port beautifully to OT, but in this case, patching, what worked so well in IT doesn't entirely fit OT — and now it's time for industry-wide innovation beyond the choice between patch, patch, patch or letting unpatched systems run vulnerably. Our goal must be to build powerful, effective processes, and then automate them to put this new approach within the reach of industrial companies and nations on a global basis. Just because we can see this better future clearly doesn't mean it is close. But let's start now to get there, together.
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