03.01.09 – System Use Notification (NIST 800-171 Rev. 3)

2025-06-15

Welcome back to our breakdown of NIST SP 800-171 Revision 3. Today we’re focusing on Control 03.01.09 – System Use Notification, part of the Access Control family.

This control ensures that any user attempting to access a system handling Controlled Unclassified Information (CUI) sees — and acknowledges — a clear warning message before access is granted.

03.01.09 – System Use Notification

Before any user logs in, the system must display a privacy and security notice that:

• States the system is for authorized use only
• Informs users that activity may be monitored
• Reminds users of their responsibilities

These messages must appear before login on any system with a human interface. If there’s no interactive user — like a background process or automated device — this control doesn’t apply.

If users don’t see it, it doesn’t count.

03.01.09 – Key Requirements

To comply with this control, organizations must:

• Display a system use notification before login
• Include privacy and security language consistent with CUI rules
• Ensure the message cannot be bypassed
• Consider whether application-level notices are also needed
• Document and approve messages through appropriate channels

03.01.09 – Implementation Tips

To implement this effectively:

• Use login banners on all systems that handle or store CUI
• Include strong, unambiguous language about monitoring and authorized use
• Display the message at both the network and application level when applicable
• Avoid casual or vague phrasing — this is a legal requirement
• Store message text in your System Security Plan (SSP) and related policies

🛡️ A good login banner isn’t just for compliance — it’s your legal shield and cultural signal.

03.01.09 – Evidence

Auditors may ask for:

• Screenshots of login banners or warning messages
• System settings showing where and how banners are enforced
• Policy documents approving the language used
• User acknowledgment records, if applicable
• Interviews with IT or legal staff who manage system access
• Audit logs (if available) showing logins preceded by the banner

Why it matters..

System use notifications make expectations clear from the moment a user interacts with a system. They also establish the legal basis for monitoring — and support broader Rules of Behavior requirements.

Security starts at the login screen — with a message that sets the tone.

• Auto-enforce login banners across systems
• Store banner language with version control
• Generate screenshots and evidence for audits
• Support Rules of Behavior compliance

Next in our NIST 800-171 Rev. 3 series: 03.01.10 – Device Lock. We’ll explore session timeout policies and how to prevent data exposure when users walk away.