In the process industry, installations run continuously. Installations can go for many months without maintenance stops, which is important for the continuity of production. After all, starting up the installation, as well as stopping it in a controlled and safe manner, often takes several days. Halting production is expensive and if the organization is part of a chain process, other companies are most likely directly involved because they no longer receive supplies or can no longer sell their products.
Restarting a computer because it has been ‘patched’ is not an option. Within these environments, alternative ‘patch’ strategies must be devised that fit within the organization’s continuous business operations. This is different from an IT environment, where a patch round is carried out in the evening, or if necessary during the weekend, to bring all operating systems and applications up to date.
An additional step is required within OT: system suppliers must approve patches in advance. If an organization does not do this, a supplier cannot guarantee that the SCADA system, for example, will continue to function and may not even provide support for unapproved patches. This results in always having to wait for approval and then also for a suitable window when these patches can be implemented. Before a patch is introduced to the production environment, it is first installed and tested in the organization’s own test environment.
Some of Hudson Cybertec’s customers have sufficient redundancy in their systems because they run as ‘hot standby’. After approval by the system supplier and extensive testing, they choose to first ‘patch’ a standby system and make it ‘live’ after the test run. This ensures a running environment to fall back on. If the patched system is stable, other systems can be patched. If issues surface that hinder a proper rollout, they will be rolled back. This will result in a phased patch rollout.
Other customers do not have this redundancy and have set up procedures to roll out patches in a structured and responsible manner. Regardless of how patching is done, it is very important that good agreements have been made within the organization to ensure patch procedures can always be followed safely and responsibly, without disrupting business continuity.
Source: Process Control, 4-2024
HUDSON CYBERTEC
