Operations, Maintenance, and Lifecycle Management
Domain 7 tests asset lifecycle practices: inventory, change control, patching, backups, vendor access, and decommissioning in a PCN.
Core rules
- Maintain an asset inventory with make, model, firmware, location, owner, network path, criticality, and end-of-support status.
- Change management requires approval, testing, scheduling, rollback planning, and documentation. Emergency changes are still documented.
- Patch management starts with vendor advisories, risk ranking, lab testing, a maintenance window, and a backup before deployment.
- Back up configurations, firmware, and licenses; test restoration, not just backup creation.
- Vendor remote access should be time-bound, monitored, MFA-protected, and free of standing accounts.
- Decommissioning removes network access, wipes data, and updates inventory and diagrams.
Worked example
A PLC firmware update fixes a denial-of-service flaw. Reasoning: verify the advisory applies, check compatibility with engineering software, back up the configuration, schedule a window, prepare a rollback image, test on a spare if available, and monitor after the change. If no spare exists, use firewall rules as a compensating control until the window.
Traps
Patching without a backup; assuming vendor firmware is compatible; leaving vendor accounts active; having no rollback path; making undocumented changes; forgetting to update the asset inventory after replacement.