Control statement
When [Organization-defined: conditions] are detected, enter a safe mode of operation with [Organization-defined: restrictions].
Discussion
For systems that support critical mission and business functions—including military operations, civilian space operations, nuclear power plant operations, and air traffic control operations (especially real-time operational environments)—organizations can identify certain conditions under which those systems revert to a predefined safe mode of operation. The safe mode of operation, which can be activated either automatically or manually, restricts the operations that systems can execute when those conditions are encountered. Restriction includes allowing only selected functions to execute that can be carried out under limited power or with reduced communications bandwidth.
Organization-defined parameters
These values must be resolved through the organization’s tailoring and governance process. Bracketed parameter references in the control text identify where a decision is required.
From control text to operational evidence
Use Safe Mode as a testable risk decision. Translate the official statement into accountable people, repeatable processes, configured technology, and evidence that demonstrates the outcome over time. In this family, pay particular attention to resilient operations, recovery priorities, alternate capabilities, and tested restoration.
Implementation workflow
- Define the control boundary, responsible owner, inherited portions, and systems or processes in scope.
- Resolve each organization-defined parameter before declaring the control implemented.
- Document how the implementation satisfies every clause of the official control statement.
- Collect evidence as a normal byproduct of operation rather than only before an assessment.
- Review exceptions, changes, and monitoring results on a risk-based cadence.
Evidence examples
- contingency and recovery plans
- backup success and restoration-test records
- exercise after-action reports
- alternate processing or communications agreements
Common failure patterns
- backups never restored in testing
- recovery priorities not tied to mission impact
- plans dependent on unavailable people or facilities
- exercise findings not tracked to closure
Questions practitioners should ask
- What risk decision is this control intended to support in this system?
- Which parts are implemented locally, inherited, shared, or not applicable—and what evidence supports that decision?
- Do the documented narrative, deployed configuration, operating process, and collected evidence agree?
- What event or threshold requires the implementation to be reviewed or changed?
Assessment objectives and methods
Show the assessment objective
a safe mode of operation is entered with [Organization-defined: restrictions] when [Organization-defined: conditions] are detected.
Examine
- Contingency planning policy
- procedures addressing safe mode of operation for the system
- contingency plan
- system design documentation
- system configuration settings and associated documentation
- system administration manuals
- system operation manuals
- system installation manuals
- contingency plan test records
- incident handling records
- system audit records
- system security plan
- other relevant documents or records
Interview
- Organizational personnel with system operation responsibilities
- organizational personnel with information security responsibilities
- system/network administrators
- system developers
Test
- Mechanisms implementing safe mode of operation
Related controls
These relationships come from the official OSCAL catalog. They indicate useful dependencies or context, not automatic inheritance or equivalence.
Authoritative sources
Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by NIST. Official control requirements and interpretations remain with NIST and the responsible authorizing organization.