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NIST SP 800-171 CUI Protection Center

03.03.07 — Time Stamps

Read the official CUI requirement and assessment content, then use the separately labeled Bare Metal Cyber perspective to connect it to implementation, evidence, and sustained operation.

1Parameters
1Source controls
3Assessment objectives
3Assessment methods

03.03 — Audit and Accountability · NIST SP 800-171 Revision 3

Active
Official NIST requirement content

Security requirement

  1. a.Use internal system clocks to generate time stamps for audit records.
  2. b.Record time stamps for audit records that meet [Organization-defined: granularity of time measurement] and that use Coordinated Universal Time (UTC), have a fixed local time offset from UTC, or include the local time offset as part of the time stamp.
Official NIST discussion

Discussion

Time stamps generated by the system include the date and time. Time is often expressed in Coordinated Universal Time (UTC) — a modern continuation of Greenwich Mean Time (GMT) — or local time with an offset from UTC. The granularity of time measurements refers to the degree of synchronization between system clocks and reference clocks (e.g., clocks synchronizing within hundreds or tens of milliseconds). Organizations may define different time granularities for system components. Time service can be critical to other security capabilities (e.g., access control and identification and authentication), depending on the nature of the mechanisms used to support those capabilities.

Official organization-defined parameters

Tailoring decisions required

Resolve these values through the governing organization’s approved tailoring and risk-management process before declaring the requirement implemented.

granularity of time measurementorganization-defined granularity of time measurementgranularity of time measurement for audit record time stamps is defined.
Bare Metal Cyber interpretation

Implementation perspective

Treat Time Stamps as a CUI protection outcome that must be reflected in the system boundary, documented implementation, operational behavior, and assessment evidence. Pay particular attention to event selection, trustworthy logging, review, retention, and support for CUI investigations.

  1. Confirm the requirement is in scope for the CUI system components, services, users, and external connections being assessed.
  2. Resolve every organization-defined parameter through an approved governance and tailoring process.
  3. Map each clause of the requirement to an accountable owner, implementation mechanism, and evidence source.
  4. Verify that inherited and shared implementations are supported by current provider evidence and responsibility boundaries.
  5. Collect evidence during normal operation and review changes, exceptions, and deficiencies on a risk-based cadence.

Questions to ask

  • Which CUI assets, data flows, users, and services are protected by this requirement?
  • Which portions are implemented locally, inherited, shared, or not applicable, and what evidence supports that determination?
  • Do the system security plan, deployed configuration, operating process, and assessment evidence tell the same story?
  • What change, incident, or threshold should trigger reassessment?

Evidence and validation

  • logging standards and event-selection decisions
  • sample audit records and retention settings
  • time synchronization evidence
  • alert review and investigation records

Common failure patterns

  • collecting logs without defined use cases
  • critical CUI events absent from the audit trail
  • retention shorter than investigative needs
  • logs modifiable by the same administrators being monitored
Official NIST SP 800-171A content

Assessment objectives and methods

Assessment objectives (3)
  1. a.

    internal system clocks are used to generate time stamps for audit records.

  2. b.

    time stamps are recorded for audit records that use Coordinated Universal Time (UTC), have a fixed local time offset from UTC, or include the local time offset as part of the time stamp.

  3. b.

    time stamps are recorded for audit records that meet [Organization-defined: granularity of time measurement].

Examine

  • audit and accountability policy and procedures
  • procedures for timestamp generation
  • system design documentation
  • system configuration settings
  • system audit records
  • system security plan
  • other relevant documents or records

Interview

  • personnel with information security responsibilities
  • system developers
  • system administrators

Test

  • mechanisms for implementing timestamp generation
Official source-control relationships

Source NIST SP 800-53 controls

These controls are referenced by the official SP 800-171 Rev. 3 OSCAL record. Open the corresponding control pages for complete control text, enhancements, D3FEND mappings, and related learning.

Source controlAU-8Open SP 800-53 control →
Source record

Authoritative sources

Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by NIST. The official publications, the responsible federal agency, and the governing contract or agreement determine applicability, tailoring, assessment depth, and required implementation.