Control statement
Request and perform data origin authentication and data integrity verification on the name/address resolution responses the system receives from authoritative sources.
Discussion
Each client of name resolution services either performs this validation on its own or has authenticated channels to trusted validation providers. Systems that provide name and address resolution services for local clients include recursive resolving or caching domain name system (DNS) servers. DNS client resolvers either perform validation of DNSSEC signatures, or clients use authenticated channels to recursive resolvers that perform such validations. Systems that use technologies other than the DNS to map between host and service names and network addresses provide some other means to enable clients to verify the authenticity and integrity of response data.
From control text to operational evidence
Use Secure Name/Address Resolution Service (Recursive or Caching Resolver) 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 secure architecture, boundary protection, communications protection, cryptography, and system isolation.
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
- network and trust-boundary diagrams
- firewall and gateway configurations
- cryptographic configuration and key records
- segmentation and isolation test results
Common failure patterns
- diagrams omit cloud and third-party paths
- encryption enabled without key governance
- flat trust zones allow unnecessary lateral movement
- boundary rules accumulate without owner review
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
- SC-21[01]data origin authentication is requested for the name/address resolution responses that the system receives from authoritative sources;
- SC-21[02]data origin authentication is performed on the name/address resolution responses that the system receives from authoritative sources;
- SC-21[03]data integrity verification is requested for the name/address resolution responses that the system receives from authoritative sources;
- SC-21[04]data integrity verification is performed on the name/address resolution responses that the system receives from authoritative sources.
Examine
- System and communications protection policy
- procedures addressing secure name/address resolution services (recursive or caching resolver)
- system design documentation
- system configuration settings and associated documentation
- system audit records
- system security plan
- other relevant documents or records
Interview
- System/network administrators
- organizational personnel with information security responsibilities
- organizational personnel with responsibilities for managing DNS
Test
- Mechanisms supporting and/or implementing data origin authentication and data integrity verification for name/address resolution services
Related controls
These relationships come from the official OSCAL catalog. They indicate useful dependencies or context, not automatic inheritance or equivalence.
Control enhancements
Enhancements add specificity, strength, or scope to the base control. Baseline badges show explicit selections in the official SP 800-53B OSCAL profiles.
SC-21(1) — Data Origin and Integrity
This enhancement is marked withdrawn in the official OSCAL catalog. Related-control metadata below may identify where its intent was incorporated.
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.