NIST 800-171 Control 3.3.8: Audit Log Protection
Audit logs are forensic records of system activity—and they're only valuable if they remain tamper-proof. Control 3.3.8 requires organizations to protect audit information and audit tools from unauthorized access, modification, and deletion. Failing to secure these records leaves you blind to security incidents and exposes you to compliance violations.
What this means
This control mandates that you safeguard both the audit data itself and the tools used to generate or analyze it. Unauthorized users must not be able to view, alter, or erase audit trails. This includes restricting write-access to audit logs, limiting who can review them, and ensuring audit tools themselves are protected from tampering. The goal is to maintain the integrity and confidentiality of your security evidence.
How to comply
- 1.Implement access controls restricting audit log viewing and modification to authorized personnel only
- 2.Configure audit logs with write-once or immutable storage to prevent modification or deletion
- 3.Use role-based access control (RBAC) to segregate audit tool access by job function
- 4.Enable audit trail features on audit tools themselves to track who accessed or changed audit configurations
- 5.Encrypt audit logs in transit and at rest to prevent unauthorized viewing
- 6.Establish retention policies aligned with your compliance framework requirements
- 7.Regularly review and validate that audit protections remain in place and effective
- 8.Restrict physical and logical access to audit servers and storage systems
Evidence auditors look for
- Log access control matrix documenting who has view, modify, and delete permissions on audit systems
- Screenshots of immutable log storage configuration (WORM settings, append-only volumes)
- Audit tool access logs showing only authorized users accessed audit configurations
- Encryption certificates or settings confirming encryption of audit data at rest and in transit
- Log retention policy documentation with approval sign-off
- Access review reports demonstrating periodic validation of audit protections
- System configuration documentation for restricted access to audit servers
Frequently asked questions
When will FAQs be available?
The FAQ for this control is currently being prepared.
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