Training & Education

How do you properly mark Controlled Unclassified Information? This guide explains how to identify, label, and protect CUI across documents, computers, digital media, manufacturing areas, and controlled workspaces. It covers core CUI marking requirements, best practices by media type, common audit-failure mistakes, and a simple step-by-step framework for building a consistent CUI marking program aligned with NIST SP 800-171, DFARS 252.204-7012, and CMMC.

If you work with the Department of Defense (DoD) or support the Defense Industrial Base (DIB), you’ve almost certainly heard the term CUI—but it’s also one of the most misunderstood concepts in compliance. Understanding Controlled Unclassified Information (CUI) is foundational to DFARS, NIST SP 800-171, and CMMC compliance. This guide breaks it down clearly and practically.