CP-10 is where plans meet reality. The statement says provide for the recovery and reconstitution of the system to a known state within a time period you define after a disruption, compromise or failure.
800-53 binds US federal systems and others by contract. It is a reference for the rest, and recovery time questions are a regular part of vendor reviews.
What it means in practice
NIST separates two ideas. Recovery is executing contingency plan activities to restore business functions. Reconstitution follows and returns systems to fully operational states. That includes turning off interim capabilities used during recovery, assessing the restored system, restarting continuous monitoring, reauthorizing if needed and preparing for future events. Both reflect your priorities, recovery point and recovery time objectives, and can be automated or manual.
The phrase known state is the important one. After a compromise, restoring from a backup that contains the attacker's changes does not return you to a known state. You need a clean image or a verified backup.
Evidence to collect
- Documented recovery time and recovery point objectives for each critical system.
- Recovery runbooks with steps and owners.
- Backup and restore test results, with measured restore times against the objective.
- Records from a real recovery or exercise, including after action notes.
- Evidence of known good images or infrastructure code used for rebuilds.
Common gaps
- Objectives are written and never measured.
- Backups run, but restores have never been tried.
- Recovery steps depend on one person.
- Reconstitution is ignored, so interim workarounds stay in production.
How to implement it
Set objectives per system tier, test restores each quarter, and time them. Rebuild from code where possible so the known state is defined in version control. Enhancements to consider are CP-10.1 Contingency Plan Testing, CP-10.2 Transaction Recovery, CP-10.3 Compensating Security Controls, CP-10.4 Restore Within Time Period, CP-10.5 Failover Capability and CP-10.6 Component Protection.
Quick check
What is the difference between recovery and reconstitution?
Recovery restores business functions using the contingency plan. Reconstitution returns systems to full operation, retires interim measures and re establishes monitoring.
