- Point everything at a reliable NTP hierarchy — domain controllers and cloud platforms mostly handle this by default; the gaps are appliances, cameras, controllers, and anything air-gapped.
- Spot-check rather than assume: pull the same event from two systems and compare the timestamps.
3.3.7OFFICIAL STATEMENT BELOWDERIVED REQUIREMENTPENDING NIST SME REVIEW
3.3.7 — Authoritative time source
3.3 Audit and Accountability · NIST SP 800-171 Rev. 2 · The heading label is this site's navigational shorthand; the official language is the statement below.
Official requirement statement (verbatim)
Provide a system capability that compares and synchronizes internal system clocks with an authoritative source to generate time stamps for audit records.
NIST SP 800-171 Rev. 2 — Protecting CUI in Nonfederal Systems ↗NIST SP 800-171A — Assessing Security Requirements for CUI ↗Independent interpretation
What this requirement is after
Correlating events across systems only works if their clocks agree. Every in-scope system synchronizes with an authoritative time source, so a 14:02 in one log and a 14:02 in another are the same moment.
Across revisions
Carried into Rev. 3 as Time Stamps (03.03.07); the emphasis shifts from the compare-and-synchronize mechanism to records carrying timestamps traceable to an authoritative source with organization-defined granularity.
Mapped practices
Brilliant at the Basics practices that support this requirement
No practice maps to this requirement — deliberately.
The campaign’s twenty practices are a priority list, not a control catalog, and none of them works this requirement’s substance directly. It still applies to you if it is in your contract’s scope: address it through your own implementation and the related artifacts below, and treat the absence of a mapping here as honesty, not permission to skip it.
Doing the work
Implementation considerations and evidence
- Time-synchronization configuration for representative system types
- A dated spot-check comparing timestamps across systems for a known event
Artifacts
Templates and worksheets with a mapped relationship
No artifact in the library names this requirement yet. The library index groups everything by category and practice.
The other revision
Where this lands in Rev. 3
Provenance
Sources and review status
| Primary sources | NIST SP 800-171 Rev. 2 — Protecting CUI in Nonfederal Systems · NIST SP 800-171A — Assessing Security Requirements for CUI |
|---|---|
| Review status | Pending NIST SME review |
| Content version | 1.0 |
| Updated |