Limit management of audit logging functionality to a subset of privileged users
📖 What This Means
This control means that only a small group of trusted, highly privileged users (like system administrators) should be able to configure, modify, or delete audit logs. Think of it like giving keys to a vault - only a few responsible people should have access. For example, in a hospital, only the head of IT (not every nurse or doctor) can change how patient access logs are recorded. Another example: in a bank, only the security team (not tellers) can adjust transaction monitoring settings. This prevents tampering with logs that might record suspicious activity.
🎯 Why It Matters
Unrestricted access to audit logs allows bad actors (including insiders) to cover their tracks after a breach. In the 2020 SolarWinds hack, attackers gained admin rights and manipulated logs to hide their activity for months. The average cost of insider threats is $15M/year (Verizon DBIR). For DoD contractors, unsecured logs mean you can't prove who accessed CUI or when - a critical compliance failure. CMMC requires this control because audit logs are worthless if they can be altered by anyone.
✅ How to Implement
- 1. In AWS: Use IAM policies to restrict 'cloudtrail:PutEventSelectors', 'logs:DeleteLogGroup', and 'logs:PutRetentionPolicy' to a dedicated Audit Admins group
- 2. In Azure: Create a Privileged Identity Management (PIM) role for 'Log Analytics Contributor' and require MFA + justification for activation
- 3. In GCP: Assign 'roles/logging.admin' only to service accounts used by your SIEM, not individual users
- 4. Enable conditional access policies requiring device compliance (e.g., enrolled MDM) for log management consoles
- 5. Configure alerts for any changes to log retention settings (e.g., AWS GuardDuty for CloudTrail modifications)
📋 Evidence Examples
IAM Policy Document for Audit Admins
Privileged User Roster
SIEM Alert Screenshot
📝 SSP Guidance
Use this guidance when writing the System Security Plan (SSP) narrative for this control.
How to Write the SSP Narrative
For AU.L2-3.3.9 ("Limit management of audit logging functionality to a subset of privileged users"), 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.L2-3.3.9 is implemented using cloud-native controls. [Organization] uses [specific cloud service/feature] to limit management of audit logging functionality to a subset of privileged users. 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.L2-3.3.9 is implemented through on-premise infrastructure controls. [Organization] uses [Active Directory/Group Policy/specific tool] to limit management of audit logging functionality to a subset of privileged users. Configuration is documented in [location] and audited [frequency]. Responsible party: [System Administrator]. Evidence: [specific artifact, e.g., 'Group Policy export, Windows Event logs']."
"AU.L2-3.3.9 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 limit management of audit logging functionality to a subset of privileged users 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.L2-3.3.9
- 📄 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 you have a documented list of personnel with privileges to configure/modify audit logs?
Question 2: Are technical controls in place to enforce these restrictions (not just policy)?
Question 3: Can you produce evidence of alerts when unauthorized attempts occur?
⚠️ Common Mistakes (What Auditors Flag)
1. Shared admin accounts used for log management
2. No alerting for log configuration changes
3. Vendor support accounts retain log access
📚 Parent Policy
This practice is governed by the Audit and Accountability Policy