Control statement
Identify critical system components and functions by performing a criticality analysis for [Organization-defined: systems, system components, or system services] at [Organization-defined: decision points in the system development life cycle].
Discussion
Not all system components, functions, or services necessarily require significant protections. For example, criticality analysis is a key tenet of supply chain risk management and informs the prioritization of protection activities. The identification of critical system components and functions considers applicable laws, executive orders, regulations, directives, policies, standards, system functionality requirements, system and component interfaces, and system and component dependencies. Systems engineers conduct a functional decomposition of a system to identify mission-critical functions and components. The functional decomposition includes the identification of organizational missions supported by the system, decomposition into the specific functions to perform those missions, and traceability to the hardware, software, and firmware components that implement those functions, including when the functions are shared by many components within and external to the system. The operational environment of a system or a system component may impact the criticality, including the connections to and dependencies on cyber-physical systems, devices, system-of-systems, and outsourced IT services. System components that allow unmediated access to critical system components or functions are considered critical due to the inherent vulnerabilities that such components create. Component and function criticality are assessed in terms of the impact of a component or function failure on the organizational missions that are supported by the system that contains the components and functions. Criticality analysis is performed when an architecture or design is being developed, modified, or upgraded. If such analysis is performed early in the system development life cycle, organizations may be able to modify the system design to reduce the critical nature of these components and functions, such as by adding redundancy or alternate paths into the system design. Criticality analysis can also influence the protection measures required by development contractors. In addition to criticality analysis for systems, system components, and system services, criticality analysis of information is an important consideration. Such analysis is conducted as part of security categorization in [RA-2](#ra-2).
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 Criticality Analysis 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 risk framing, threat and vulnerability analysis, impact, criticality, and response decisions.
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
- risk assessments and threat models
- vulnerability findings and prioritization records
- supply-chain risk assessments
- risk response and acceptance decisions
Common failure patterns
- risk registers detached from technical evidence
- vulnerability severity treated as business impact
- assessments not updated after material change
- accepted risks have no owner or expiration
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
critical system components and functions are identified by performing a criticality analysis for [Organization-defined: systems, system components, or system services] at [Organization-defined: decision points in the system development life cycle].
Examine
- Risk assessment policy
- assessment reports
- criticality analysis/finalized criticality for each component/subcomponent
- audit records/event logs
- analysis reports
- system security plan
- other relevant documents or records
Interview
- Organizational personnel with assessment and auditing responsibilities
- organizational personnel with criticality analysis responsibilities
- system/network administrators
- organizational personnel with security responsibilities
Test
- Organizational processes for assessments and audits
- mechanisms/tools supporting and/or implementing assessments and auditing
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.