Mapped to NIST 800-171 Requirement: 3.1.3
CMMC Assessment Objective: AC.L2-3.1.3[b]
What This Objective Means
While AC.L2-3.1.3[a] focuses on defining authorized CUI flow, this objective ensures those definitions are actively enforced by your systems. You must demonstrate that technical controls are in place to ensure CUI only flows:
• Through approved communication paths
• To approved systems and users
• Using authorized services and protocols
This includes both network-level controls and application-level safeguards.
Why It Matters
If your systems don’t enforce data flow restrictions:
• CUI could be sent over unsecured or unmonitored channels
• You won’t know when CUI is leaked or mishandled
• Compliance is at risk, and audits will flag the gap
The system—not just the policy—must do the heavy lifting.
How to Implement It
• Use firewalls and access control lists (ACLs) to restrict traffic between zones
• Apply DLP (Data Loss Prevention) tools to monitor and block unauthorized transfers
• Use web filtering or email gateways to prevent CUI from being sent externally
• Ensure CUI-related applications limit exports, downloads, or sharing
• Conduct regular testing or audits to confirm controls are in place and functioning
Evidence the Assessor Will Look For
• Firewall and routing configurations showing allowed and blocked traffic paths
• System settings or logs demonstrating flow restrictions (e.g., denied transmissions)
• Screenshots from DLP, secure file-sharing tools, or endpoint protection
• Verification that access is blocked to unapproved systems or cloud storage
Common Gaps
• Having policies on CUI flow, but no technical enforcement
• No restrictions on file uploads or downloads to personal email or cloud apps
• Inconsistent controls between departments or systems
How Cuick Trac Helps
Cuick Trac enforces CUI flow control by:
• Using a pre-configured, segmented enclave with built-in firewall rules and data boundaries
• Blocking unauthorized access to external storage or file-sharing tools
• Monitoring all traffic in and out of the enclave to detect unapproved CUI transfers
• Supporting exportable documentation and logs to prove enforcement
With Cuick Trac, you don’t just say CUI is controlled—you prove it at the system level.
Final CTA
Controlling the flow of CUI is a technical challenge—not just a policy one.
Schedule a Cuick Trac demo and see how system-level enforcement protects your most sensitive data.