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SC-45(2) SC · System and Communications Protection

Secondary Authoritative Time Source

LOW MODERATE HIGH
1 Overlay 0 Related Controls
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Requirements NIST SOURCE

Discussion (NIST Supplemental Guidance)

It may be necessary to employ geolocation information to determine that the secondary authoritative time source is in a different geographic region.

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-45(2) 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

  1. a secondary authoritative time source is identified that is in a different geographic region than the primary authoritative time source;
  2. the internal system clocks are synchronized to the secondary authoritative time source if the primary authoritative time source is unavailable.

Examine

[SELECT FROM: System and communications protection policy; procedures addressing time synchronization; 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 installing, configuring, and/or maintaining the system].

Test

[SELECT FROM: Mechanisms supporting and/or implementing system time synchronization with secondary authoritative time sources].

Overlays

Showing the OT/ICS overlay for the parent control SC-45 — see the SC-45(2) entries within each baseline below.

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: Added (beyond standard baseline)

MODERATE

  • Base control: Added (beyond standard baseline)

HIGH

  • Base control: Added (beyond standard baseline)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for SC-45(2). 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 system time synchronization with secondary authoritative time sources

Other Records

  • procedures addressing time synchronization
  • system audit records
  • other relevant documents or records