← SC-45
SC-45(1) SC · System and Communications Protection

Synchronization with Authoritative Time Source

LOW MODERATE HIGH
1 Overlay 0 Related Controls
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Requirements NIST SOURCE

Discussion (NIST Supplemental Guidance)

Synchronization of internal system clocks with an authoritative source provides uniformity of time stamps for systems with multiple system clocks and systems connected over a network.

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(1) 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. the frequency at which to compare the internal system clocks with the authoritative time source is defined;
  2. the authoritative time source to which internal system clocks are to be compared is defined;
  3. the time period to compare the internal system clocks with the authoritative time source is defined;
  4. the internal system clocks are compared <SC-45(01)_ODP[01] frequency> with <SC-45(01)_ODP[02] authoritative time source>;
  5. the internal system clocks are synchronized with the authoritative time source when the time difference is greater than <SC-45(01)_ODP[03] time period>.

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].

Overlays

Showing the OT/ICS overlay for the parent control SC-45 — see the SC-45(1) 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(1). 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

Other Records

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