03.01.02 – Access Enforcement (NIST 800-171 Rev. 3)

2025-05-25

Welcome to our breakdown of 03.01.02 – Access Enforcement, the second control in the Access Control family under NIST SP 800-171 Rev. 3.

While 03.01.01 focuses on who gets access, this control ensures that access is actually enforced — not just approved on paper.

03.01.02 – Access Enforcement

Once accounts are provisioned, systems must take action to enforce access restrictions as defined in your access control policies.

This applies to all kinds of system interactions — including local, remote, and cloud-based access.

03.01.02 – Key Requirements

• Implement mechanisms that enforce logical access controls
• Ensure authorizations are configured to match your written policies
• Enforce access to CUI based on roles, responsibilities, and need-to-know
• Cover all access vectors — from apps and databases to remote logins and APIs

03.01.02 – Implementation Tips

Here’s how to implement this control effectively:

• Map access levels to job roles in your Access Control Policy
• Use role-based access control (RBAC) or attribute-based access control (ABAC) to enforce access
• Apply least privilege to ensure users only get the access they truly need
• Use groups, roles, and policies to automate access enforcement
• Regularly audit systems and permissions for drift or overprovisioning

And don’t forget testing — verifying your enforcement mechanisms is just as important as configuring them.

03.01.02 – Evidence

Auditors may ask for:

• The access control policy and enforcement procedures
• System configuration files showing access enforcement
• Logs showing both successful and denied access attempts
• A list of current user privileges and associated roles
• Screenshots or exports from tools like Active Directory or IAM dashboards

Include in your SSP

You’ll document this control in your System Security Plan (SSP) by describing:

• How your systems enforce access control
• Which technologies or services apply those rules
• How enforcement is verified and monitored over time

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Why it matters..

Even if your policies are perfect on paper — without real enforcement, they’re meaningless.
Access Enforcement is how you turn intent into actual protection for Controlled Unclassified Information (CUI).

It’s not just about access — it’s about control.

• Access policy enforcement tracking
• System-based evidence uploads
• Automated control scoring
• Role-based compliance dashboards

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Stay tuned for the next post in this series:
03.01.03 – Information Flow Enforcement
We’ll cover how to control where CUI goes — and how to block it from where it shouldn’t.

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