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Patch Management for Industrial Control Systems

A key component in protecting a nation’s critical infrastructure and key resources is the security of control systems. Security patch management is a delicate issue in critical infrastructure.

Patching IT systems is hard, but it’s even more difficult to patch industrial control systems (ICS), commonly found in energy, manufacturing, pharmaceuticals and other verticals powered by Operational Technology (OT) networks that pre-date the Internet. These systems, which have been controlling complex machinery for years, run constantly and have constrained maintenance windows, and often rely on custom software tied to older, no-longer supported versions of operating systems. A patch might very well crash the system, and in the ICS world reliability and uptime are the priority.

We’ve all seen them – notifications regarding software updates – on our home and office computers. Those in the control room see similar notifications regarding software updates. Unfortunately, the decision to trust an update without proper validation for a control system is more difficult than other systems. If an update is applied and something goes wrong, the operational implications can be quite costly. This has led to a nonessential attitude towards security patch management, where unpatched software – whether it’s vulnerable firmware or older versions of software – remains unpatched for extended periods of time.

Despite the challenges of securing an industrial control system, a robust patching program for IT and OT environments can be a reality. It requires a cyclical and consistently monitored program be put in place to ensure a secure and healthy system. We know that patch management is a maze of processes and procedures supported by a combination of automated and manual efforts. From Asset ID to Patch Deployment we’ve got you covered. Make note though, these are not isolated processes. The information gathered during each phase has an impact on almost all other aspects of patch management. Consider the following patch management process phases:

Asset ID & Baseline

Prior to monitoring patch data, it is crucial for you to properly document all critical assets from which to build a baseline


Once you have your asset inventory, continuously monitor this list to know when security patches are available and document/define how your systems are impacted and can be protected.


Evaluating released security patches for applicability of devices and software used in your environment is the next step. Security engineers should review your network configuration and provide recommendations around installation of patches released within a specified time frame. 


Next, acquire and authenticate applicable patches for delivery in a single, comprehensive deliverable. Make sure that the acquisition of patches is via a secure electronic download and/or tamper-resistant physical distribution via physical media.


Patch Validation is a tedious, timely process that requires the right staff with the right aptitude in the right environment to safely and effectively test patches. This may require special equipment and the right discernment to understand how much and how deep to test each of your critical assets.


A diligent deployment process defends against malware, in-transit modification and corruption. A comprehensive, secure and easy-to-use patch deployment solution that best fits the needs of your specific environment is a must.

In summary, the OT security threat is real and the complexity of patching ICS systems magnifies it. When it comes to patching ICS networks, there’s plenty we have learned from our field experience with over a decade of patch delivery experience in IT and OT space. FoxGuard can centralize your patch management burden in a simplified, cost-effective, and timely fashion; and facilitate a more secure environment by being up-to-date with critical updates & patches and perform all the aforementioned steps as part of our comprehensive patch management solution.

FoxGuard provides a wide range of patch management solutions that help entities identify and mitigate gaps in the security of their systems and prepare for security audits. We host a webinar series to discuss ways to develop and implement a robust patch management program. Reserve your spot in our next session.


If you want to discuss something specific, we will do that too! Just reach out, tell us what your challenges are, and we will have one of our security experts contact you.