NIST SP 800-53 SC-21 Secure Name/Address Resolution Service (Recursive or Caching Resolver)

Requirements NIST SOURCE

Request and perform data origin authentication and data integrity verification on the name/address resolution responses the system receives from authoritative sources.

Discussion (NIST Supplemental Guidance)

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.

Implementation Guidance

Engineering Interpretation

Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.

No engineering interpretation has been authored for SC-21 yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.

Assessment

NIST SP 800-53A REV 5.2.0

Assessment Objectives

data origin authentication is requested for the name/address resolution responses that the system receives from authoritative sources;
data origin authentication is performed on the name/address resolution responses that the system receives from authoritative sources;
data integrity verification is requested for the name/address resolution responses that the system receives from authoritative sources;
data integrity verification is performed on the name/address resolution responses that the system receives from authoritative sources.

Examine

[SELECT FROM: 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

[SELECT FROM: System/network administrators; organizational personnel with information security responsibilities; organizational personnel with responsibilities for managing DNS].

Test

[SELECT FROM: Mechanisms supporting and/or implementing data origin authentication and data integrity verification for name/address resolution services].

Overlays

OT/ICS Overlay SP 800-82r3

NIST SP 800-82r3 Appendix F, Table 22. Blank baseline means the control/control enhancement is not selected in that initial OT baseline.

LOW

Base control: Included (matches standard baseline)

MODERATE

Base control: Included (matches standard baseline)

HIGH

Base control: Included (matches standard baseline)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for SC-21. This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.

Learn more about STIG/CCI integration →

Evidence

Potential Evidence — Derived

Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.

Policy

System and communications protection policy
system security plan

Configuration

system design documentation
system configuration settings and associated documentation

Testing

Mechanisms supporting and/or implementing data origin authentication and data integrity verification for name/address resolution services

Other Records

procedures addressing secure name/address resolution services (recursive or caching resolver)
system audit records
other relevant documents or records