Provide a system capability that compares and synchronizes internal system clocks
📖 What This Means
This practice ensures that all systems within your network have synchronized clocks, meaning they all show the same accurate time. This is crucial because accurate timestamps on logs and events are necessary for investigating security incidents and ensuring accountability. Without synchronized clocks, it becomes difficult to correlate events across different systems, making it harder to detect and respond to threats. For example, if one system logs an event at 10:00 AM and another logs a related event at 10:05 AM, but their clocks are out of sync, it could appear as if the events occurred at completely different times. This practice helps prevent such confusion.
🎯 Why It Matters
Unsynchronized clocks can lead to inaccurate log data, making it difficult to trace security incidents back to their source. This can delay incident response and compromise forensic investigations. For instance, in the 2017 Equifax breach, inconsistent timestamps across logs complicated the investigation, delaying the identification of the attack vector. The DoD emphasizes this control because accurate time synchronization is essential for effective audit logging, which is a cornerstone of cybersecurity defense. Without it, organizations risk misaligning events, leading to incomplete or incorrect security analyses. This can result in prolonged system downtime, increased recovery costs, and damage to reputation.
✅ How to Implement
- Identify all cloud instances and services that require time synchronization.
- Configure Network Time Protocol (NTP) settings in your cloud provider's management console (e.g., AWS Systems Manager, Azure Virtual Machines, GCP Compute Engine).
- Set up a centralized NTP server or use a trusted external NTP source (e.g., time.google.com).
- Ensure all virtual machines and containers are configured to sync with the NTP server.
- Monitor and validate synchronization using cloud-native monitoring tools (e.g., AWS CloudWatch, Azure Monitor).
- Document the configuration and include it in your security policies.
- Regularly test synchronization accuracy using tools like 'ntpq' or 'chronyc'.
📋 Evidence Examples
NTP Configuration Documentation
Synchronization Test Results
Screenshot of NTP Settings
Monitoring Logs
Policy Document
📝 SSP Guidance
Use this guidance when writing the System Security Plan (SSP) narrative for this control.
How to Write the SSP Narrative
For AU.L2-3.3.7 ("Provide a system capability that compares and synchronizes internal system clocks"), your SSP narrative should specifically describe: (1) the tools and technologies you use to implement this control, (2) the configuration or process that enforces it, (3) who is responsible for maintaining it, and (4) what evidence proves it's working. Describe your audit logging infrastructure, including which events are logged, the SIEM/log management platform, retention periods, log protection mechanisms, and review processes. Be specific -- name your actual products, settings, and responsible personnel.
Example SSP Narratives
"AU.L2-3.3.7 is implemented using cloud-native controls. [Organization] uses [specific cloud service/feature] to provide a system capability that compares and synchronizes internal system clock.... The configuration is managed through [Azure Policy/AWS Config/Terraform] and monitored via [SIEM tool]. Responsible party: [IT Security Manager]. Evidence: [specific artifact, e.g., 'Azure AD Conditional Access policy screenshot, CloudTrail logs']."
"AU.L2-3.3.7 is implemented through on-premise infrastructure controls. [Organization] uses [Active Directory/Group Policy/specific tool] to provide a system capability that compares and synchronizes internal system clock.... Configuration is documented in [location] and audited [frequency]. Responsible party: [System Administrator]. Evidence: [specific artifact, e.g., 'Group Policy export, Windows Event logs']."
"AU.L2-3.3.7 is implemented across both cloud and on-premise environments. [Organization] uses [Azure AD Connect/hybrid tool] to ensure consistent enforcement. Cloud resources are managed via [cloud tool] and on-premise systems via [on-prem tool]. Both environments report to [centralized SIEM]. Responsible party: [IT Director]. Evidence: [artifacts from both environments]."
System Boundary Considerations
- • Identify all systems generating audit logs within the CUI boundary
- • Document log flow from sources to centralized SIEM
- • Specify log storage locations and retention tiers
- • Ensure this control covers all systems within your defined CUI boundary where provide a system capability that compares and synchronizes internal system clocks applies
- • Document any systems where this control is not applicable and explain why
Key Documentation to Reference in SSP
- 📄 Audit and Accountability Policy
- 📄 SIEM architecture documentation
- 📄 Log retention configuration
- 📄 Evidence artifacts specific to AU.L2-3.3.7
- 📄 POA&M entry if control is not fully implemented
What the Assessor Looks For
The assessor will verify that required events are logged, check log completeness (all required fields present), test log protection mechanisms, and review evidence of regular log reviews.
💬 Self-Assessment Questions
Use these questions to assess your compliance. Each "NO" answer provides specific remediation guidance.
Question 1: Do all systems in your network have synchronized clocks?
Question 2: Is there a documented policy for time synchronization?
Question 3: Are synchronization tests conducted regularly?
Question 4: Are synchronization logs reviewed and maintained?
Question 5: Is synchronization accuracy monitored for drift?
⚠️ Common Mistakes (What Auditors Flag)
1. Using untrusted NTP sources.
2. Not documenting NTP configurations.
3. Failing to test synchronization regularly.
4. Ignoring synchronization drift.
5. Not including all devices in synchronization.
📚 Parent Policy
This practice is governed by the Audit and Accountability Policy