NIST SP 800-171 Control 3.5.2: User Authentication
Control 3.5.2 requires organizations to authenticate user, process, and device identities before granting access to systems—a foundational security practice for protecting CUI. Without proper authentication, unauthorized actors can infiltrate your network and compromise sensitive data. This control is non-negotiable for NIST 800-171 compliance and directly reduces breach risk.
What this means
User authentication means verifying that the person, application, or device requesting access is genuinely who or what they claim to be. This prerequisite check happens before any system access is granted. Authentication must cover users logging into systems, automated processes running on behalf of applications, and devices connecting to your network. The control ensures only legitimate entities can interact with your infrastructure and data.
How to comply
- 1.Deploy multi-factor authentication (MFA) for user logins, requiring at least two verification methods (password + token, biometric, smart card)
- 2.Establish authentication protocols for automated processes and service accounts using API keys, certificates, or cryptographic credentials
- 3.Implement device identity verification for any endpoint connecting to your network (laptops, servers, IoT devices)
- 4.Configure your identity and access management (IAM) system to enforce authentication at every entry point
- 5.Document authentication mechanisms for each system and user type in your security plan
- 6.Test authentication controls regularly to confirm they block unauthorized access attempts
- 7.Monitor authentication logs for failed attempts and suspicious patterns
Evidence auditors look for
- MFA configuration screenshots showing password + SMS/app token requirements
- IAM policy documentation listing authentication standards for users and service accounts
- Certificate or API key inventory for automated processes and device authentication
- Authentication logs showing successful and failed login attempts over 30-90 days
- Device onboarding procedures requiring identity verification before network connection
- Security awareness training records confirming staff understand authentication requirements
- Authentication system test results validating that unauthorized access is blocked
Frequently asked questions
When will FAQs be available?
The FAQ for this control is currently being prepared.
GRCWatch automatically maps your authentication systems (AD, Okta, MFA tools) to control 3.5.2, generates audit-ready evidence reports, and alerts you when authentication policies drift—eliminating manual log reviews and reducing compliance assessment time.
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