How do we balance high availability with critical security patching in OT environments?

All answers to this question.

In my experience managing automotive assembly lines, you must move away from the IT mindset of "patch everything immediately." Instead, we utilize a risk-based vulnerability management approach. We prioritize patches that address remote code execution vulnerabilities while using compensating controls, like network segmentation and industrial firewalls, for less critical bugs. We only deploy patches during our semi-annual planned maintenance shutdowns. We also mirror our OT environment in a small test lab to verify that a patch won't cause logic errors in the PLCs before going live on the floor.

   Answered 2025-05-15 by Brenda Collins

Brenda, that test lab setup sounds expensive to maintain. Do you find that virtualized twins of your ICS environment are accurate enough to predict how hardware-level patches will react during a real-time cycle?

   Answered 2025-05-17 by Brenda

• Brenda, while digital twins aren't perfect, they catch 90% of the 'show-stopper' conflicts. For the remaining 10%, we rely on robust backup and recovery images created via specialized OT backup tools before we even touch the production machine. It’s about layers of safety.

     Commented 2025-05-17 by Mark Thompson

Focus on virtual patching through a Web Application Firewall or an IPS. This blocks the exploit at the network level without needing to modify the sensitive firmware on the legacy device itself.

   Answered 2025-05-19 by Patricia Williams

• I agree with this. Virtual patching is a lifesaver for Windows XP or older machines that are no longer supported by vendors but are still essential to the production line.

     Commented 2025-05-25 by Sarah Jenkins