03.03.07: Time Stamps

To meet the 03.03.07: time stamps requirement, you must ensure audit records and other security-relevant events are stamped with accurate, consistent time, sourced from an authoritative time service, and synchronized across systems that handle CUI. Operationally, that means standardizing time configuration, setting drift expectations, monitoring sync health, and retaining evidence that time is correct and enforced. ¹

Key takeaways:

• Standardize a single authoritative time source and enforce it across in-scope systems that store or process CUI. ¹
• Time stamping is an auditability control; weak time sync breaks investigations, incident response, and log correlation. ¹
• Treat time settings and sync status as compliance evidence: configs, monitoring, and exception handling. ¹

03.03.07: time stamps requirement sounds narrow, but assessors treat it as a foundation for every control that depends on trustworthy logs: incident response, detection engineering, access monitoring, and forensics. If timestamps vary across endpoints, servers, cloud platforms, and security tools, you cannot reliably reconstruct what happened, in what order, and by which identity. That becomes a direct problem in a CUI environment because you must be able to demonstrate control operation and investigate security events credibly. ¹

Operationalizing this requirement means making time a managed security setting, not a default. You need (1) an authoritative time source, (2) enforced configuration across in-scope assets, (3) monitoring for drift and sync failure, and (4) documented procedures for exceptions (isolated networks, OT, legacy systems, and disconnected laptops). You also need evidence that these controls run continuously, not just on audit day. ¹

This page gives requirement-level implementation guidance you can hand to IT operations and security engineering, then map directly into policy, your SSP/POA&M, and recurring evidence collection.

Regulatory text

Requirement: “NIST SP 800-171 Rev. 3 requirement 03.03.07 (Time Stamps).” ¹

What the operator must do: Implement technical and procedural controls so that security-relevant records (especially audit logs) have accurate timestamps that can be correlated across systems handling CUI. In practice, that means configuring time synchronization to an authoritative source, standardizing time settings (time zone/UTC handling), and proving the configuration is enforced and monitored across the CUI boundary. ¹

Plain-English interpretation

You need logs you can trust. Trustworthy logs require timestamps that are:

• Consistent across systems (so event ordering makes sense).
• Accurate enough for investigations (so you can correlate events across endpoints, servers, identity providers, and network/security tools).
• Resistant to easy manipulation (so users and admins cannot casually alter time to hide activity).
• Operationally monitored (so you notice when sync breaks, not after an incident). ¹

If you already “have logs,” that’s not sufficient. Assessors will probe whether the timestamps can be relied on during a security incident affecting CUI. ¹

Who it applies to

Entities

• Federal contractors and subcontractors that handle CUI in nonfederal systems. ¹

Operational scope

• Systems in your CUI enclave or boundary: endpoints, servers, virtual infrastructure, directory services, security tools (SIEM, EDR), jump hosts, and logging pipelines.
• Cloud services that store/process CUI (where you control time settings indirectly through service configuration and log settings).
• Third parties that operate managed infrastructure or SOC functions for your CUI environment (because timestamp integrity affects shared investigations and reporting). ¹

What you actually need to do (step-by-step)

1) Define the “authoritative time” design

Make a written decision that answers four questions:

• What is the authoritative source? Common patterns: internal NTP stratum backed by trusted upstream sources; cloud-native time sync for cloud workloads; domain hierarchy for Windows environments.
• What is the standard time format? Decide how you will treat UTC vs local time zones for logs. Most teams standardize log ingestion to UTC even if hosts display local time.
• What is the in-scope boundary? Identify all hosts and platforms that generate logs used for CUI security monitoring.
• What are allowed exceptions? Air-gapped segments, OT, or legacy platforms might need compensating controls. ¹

Deliverable: “Time Synchronization Standard” (a short engineering standard) referenced by your security policy and SSP. ¹

2) Inventory time sync status for in-scope assets

You cannot fix what you cannot see. Build an inventory view that includes:

• Asset identifier and owner
• OS/platform type (Windows, Linux, network devices, hypervisor, SaaS)
• Current time sync method (domain time, NTP, cloud provider service)
• Current sync health status and last sync time
• Admin controls (who can change time settings) ¹

Operator tip: Your assessor will accept a CMDB export, EDR inventory, MDM inventory, or cloud asset inventory as the starting point, as long as you can show it maps to the CUI boundary and is kept current. ¹

3) Enforce configuration by platform (don’t rely on “best effort”)

Implement configuration controls that make the desired state repeatable:

Windows

• Enforce Windows Time service settings by GPO for domain-joined systems.
• Restrict “Change the system time” privilege to a small admin group.
• Ensure domain controllers follow a known hierarchy and have a stable upstream reference. ¹

Linux

• Standardize on chrony or equivalent; enforce config through your configuration management tooling.
• Lock down who can change time settings; monitor for manual time changes.
• Standardize NTP servers across the enclave to reduce drift variance. ¹

Network/security appliances

• Configure NTP in device management standards.
• Ensure devices log with time zone/UTC explicitly (avoid ambiguous local timestamps). ¹

Cloud

• For IaaS: use provider-supported time sync and ensure images/baselines retain it.
• For SaaS logs: confirm event timestamps include timezone/UTC and that your SIEM normalizes them. ¹

4) Centralize log ingestion and normalize timestamps

Time stamps only become useful if your log pipeline preserves and normalizes them.

• Confirm your SIEM/log platform records both event time and ingest time.
• Normalize to a single standard (commonly UTC) on ingest.
• Ensure parsing rules correctly interpret timezone offsets. ¹

Common hangup: Teams pass the control because endpoints sync time, then fail during testing because the SIEM parser shifts timestamps due to timezone assumptions. Treat parsing as part of the control. ¹

5) Monitor and alert on time sync failures and drift

Build an operational mechanism to detect:

• NTP/chrony service stopped
• Host cannot reach time source (network, DNS, firewall)
• Excessive drift relative to expected range
• Manual time changes (where available via audit logs) ¹

Route alerts to the team that can fix them (IT ops or endpoint team), and track remediation in your ticketing system.

6) Document exceptions and compensating controls

For systems that cannot sync time normally, document:

• Why (technical limitation, isolation requirements)
• How time is set (manual process, maintenance windows)
• How logs are handled (separate correlation assumptions, additional contextual logs)
• Approvals and review cadence ¹

7) Build “audit-ready” recurring evidence

Turn this into repeatable compliance evidence:

• Monthly evidence pack (or your chosen cadence) with samples across asset classes
• Change control records for time configuration
• Incident tickets where time sync broke and was remediated ¹

Daydream (or any GRC workflow tool) fits naturally here: map 03.03.07 to specific technical controls, assign owners, and schedule recurring evidence requests so you are not rebuilding proof during an assessment. ¹

Required evidence and artifacts to retain

Keep evidence that shows both design and operation:

Policy / standards

• Information security policy referencing time synchronization expectations
• Time Synchronization Standard (authoritative sources, approved protocols, logging standard) ¹

System configuration

• GPO screenshots/exports for Windows time settings
• Linux chrony/ntpd config snippets plus configuration management records
• Network device NTP config snapshots (sanitized)
• Cloud build/baseline documentation showing time sync preserved ¹

Operational proof

• Monitoring dashboards or reports showing sync status
• Alert examples and tickets showing investigation and remediation
• SIEM proof: sample events from multiple sources showing consistent timestamp normalization ¹

Scope proof

• Asset inventory for CUI boundary and sampling methodology for evidence collection ¹

Common exam/audit questions and hangups

Assessors and internal auditors commonly ask:

• “What is your authoritative time source, and who owns it?” ¹
• “Show me how you prevent a standard user (or most admins) from changing system time.” ¹
• “Pick three endpoints, two servers, and a key security tool. Prove they’re synchronized.” ¹
• “Do your logs store timezone/UTC clearly, and does the SIEM normalize consistently?” ¹
• “How do you detect and respond to time sync failures?” ¹
• “What are the exceptions in the enclave, and what compensating controls exist?” ¹

Frequent implementation mistakes and how to avoid them

Mistake	Why it fails	How to avoid
Relying on default time settings	Defaults differ across images, cloud services, and network segments	Publish a standard and enforce with GPO/config management 1
No monitoring for sync failures	You only learn about drift during an incident or assessment	Add alerting for service down, unreachable NTP, drift indicators 1
SIEM timezone parsing errors	Correlation breaks even if hosts are correct	Validate parsers, store event and ingest time, normalize to a standard 1
Too many people can change time	A malicious actor can distort timelines	Restrict privileges; log/admin monitoring for time changes 1
Exceptions handled informally	Assessors treat exceptions as control gaps	Document exceptions with approvals and compensating controls 1

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so you should treat it as an assessment-readiness and incident-readiness risk rather than a “case law” requirement.

Risk implications are still concrete:

• Incident reconstruction risk: If timestamps are unreliable, you cannot defend your investigation narrative or determine impact windows for CUI exposure. ¹
• Control testing risk: Many controls depend on log correlation; time drift creates false negatives and false positives in detection and audit testing. ¹
• Third-party coordination risk: If a managed SOC or IR firm ingests your logs, inconsistent timestamps slow containment and complicate reporting. ¹

Practical execution plan (30/60/90-day)

You asked for speed. Use this as an operator playbook, then adapt to your environment.

First 30 days (stabilize design and scope)

• Name the control owner (security engineering or IT ops) and define the authoritative time source(s). ¹
• Confirm the CUI boundary asset list and identify logging-critical systems (IdP, SIEM, EDR, key servers). ¹
• Draft the Time Synchronization Standard and get it approved through your security governance process. ¹
• Run a spot check across representative assets to identify drift/sync failures and timezone inconsistencies in the SIEM. ¹

Days 31–60 (enforce and instrument)

• Implement GPO/config management baselines for time settings across endpoints and servers. ¹
• Standardize NTP settings for network/security appliances in the enclave. ¹
• Add monitoring and alert routing for time sync failures; integrate with ticketing. ¹
• Validate SIEM normalization with test events from each major source type and fix parser/timezone issues. ¹

Days 61–90 (prove operation and close gaps)

• Document exceptions and compensating controls; link them to POA&M items if remediation is pending. ¹
• Build a recurring evidence pack: config exports, monitoring snapshots, sample correlated events, and closed tickets. ¹
• Run an internal control test: select a sample set of assets, demonstrate sync, demonstrate restricted privileges, demonstrate SIEM correlation. ¹
• In Daydream, map 03.03.07 to the evidence checklist and schedule automated reminders to collect proofs on a recurring cadence. ¹

Frequently Asked Questions

What systems are “in scope” for the 03.03.07: time stamps requirement?

Any system that handles CUI or produces logs you rely on to secure CUI is in scope, including endpoints, servers, identity services, and your logging pipeline. Treat security tooling as in scope if you use it to detect or investigate CUI-related events. ¹

Do I need to use NTP specifically?

NIST SP 800-171 Rev. 3 states the time stamps requirement but does not prescribe one protocol in the provided excerpt. Use an authoritative, managed time synchronization approach appropriate to your environment and document the standard you enforce. ¹

How do we handle laptops that are off-network for long periods?

Enforce time sync when they reconnect (VPN or direct) and monitor for endpoints that fail to sync for extended periods. Document your exception handling for disconnected periods and ensure endpoint logs still normalize correctly when ingested. ¹

What evidence is the fastest way to satisfy an assessor?

Provide your approved time standard, enforced configurations (GPO/config management outputs), and monitoring proof plus a small set of cross-system log samples showing consistent timestamps in the SIEM. Pair that with tickets showing you detect and fix sync failures. ¹

We have multiple cloud services. Do we need to prove their clocks too?

Yes, if their logs are part of your security monitoring for CUI, you must show timestamps are consistent and interpretable. Often the proof is a combination of provider log settings and SIEM normalization, not host-level NTP configs. ¹

How should we document exceptions without creating audit pain?

Maintain a short exception register with system name, business justification, compensating controls, and an owner. Tie exceptions to tickets or POA&M items and keep approval records so exceptions read as managed risk, not neglect. ¹

Footnotes

1. NIST SP 800-171 Rev. 3