How to Identify CUI Within Your Environment, Set a CUI Boundary for CMMC, and Why Continuous Monitoring Is No Longer Optional

Mike Mitchell
Jan 16
3 min read

Updated: Jan 20

For years, Controlled Unclassified Information (CUI) lived in an uncomfortable gray area. Contractors knew they had it, knew it mattered, but often treated it as a documentation problem rather than a data problem.

That era is over.

Recent updates to DFARS and mandates flowing from the National Defense Authorization Act (NDAA) have turned cui identification into a contractual, auditable requirement. Defense contractors are now expected to know—precisely and continuously—where CUI exists, how it is protected, and whether it ever strays outside authorized boundaries.

If you can’t answer those questions with evidence, your CMMC posture is fragile by definition.

Why it's Difficult to Identify CUI

In theory, identifying CUI sounds straightforward: find the data, label it, protect it.

In reality, most DIB environments look like this:

Years of unstructured data spread across file shares, SharePoint, OneDrive, email, and endpoints
Legacy documentation mixed with live operational data
Engineers, program managers, and subcontractors collaborating across platforms
Data copied, exported, backed up, and re-shared outside of original workflows

Manual discovery breaks immediately at this scale. Even disciplined teams fall behind the moment data moves faster than their spreadsheets.

Many organizations attempt to solve this with existing tools, but those approaches introduce their own problems:

Manual Identification

Labor-intensive and impossible to keep current
Dependent on user judgment and tribal knowledge
Produces snapshots, not living evidence

DLP and DSPM Platforms

Designed for broad “sensitive data,” not CUI specificity
Generate excessive false positives
Rarely align cleanly with CMMC scoping expectations

Microsoft Purview

Useful for labeling and information protection
Heavily dependent on rules, tuning, and ongoing governance
Does not inherently provide authoritative, continuous visibility into where CUI truly resides

The result is a dangerous illusion of control. Many organizations believe they understand their CUI footprint—until an assessor, incident, or regulator proves otherwise.

Why This Matters Now More Than Ever

The final DFARS rule implementing CMMC makes certification a contractual requirement, not a policy aspiration. Contracts will increasingly require:

Valid CMMC certification tied to specific systems
Accurate scoping of environments that store, process, or transmit CUI
Ongoing affirmation that cybersecurity controls remain in place

In parallel, the NDAA has reinforced the federal government’s position that CUI exposure is a national security issue, not an administrative oversight. Poor CUI handling is now framed as a supply chain risk with real-world consequences.

That shift changes the risk calculus:

If CUI is outside your defined boundary, your scope is wrong
If your scope is wrong, your certification is vulnerable
If your certification is vulnerable, your contracts are at risk

This is why cui identification is no longer a preliminary step. It is the foundation of defensible compliance.

Setting a Defensible CUI Boundary for CMMC

CMMC scoping depends entirely on knowing where CUI exists. You cannot draw a boundary around data you haven’t accurately identified.

A defensible CUI boundary requires:

Environment-wide discovery across structured and unstructured data
Clear mapping of CUI locations to systems and repositories
Documentation that supports why certain systems are in scope—and why others are not

Without this, organizations either under-scope (creating compliance gaps) or over-scope (driving unnecessary cost and complexity). Both outcomes are common. Neither is sustainable.

Why Continuous Monitoring Is the Missing Piece

Even organizations that successfully identify and scope CUI at a point in time often fail later for one simple reason: data does not stand still.

New files are created. Old files are copied. Teams collaborate in new ways. Systems change.

A one-time discovery exercise cannot support continuous compliance, and DFARS now expects exactly that—ongoing alignment between certification claims and operational reality.

Continuous monitoring ensures:

Newly created or moved CUI is identified automatically
CUI remains within authorized boundaries
Drift is detected before it becomes a finding, incident, or contractual issue

This is where most traditional approaches break down. They were never designed to maintain persistent, auditable visibility into CUI over time.

The Path Forward

The DIB is transitioning from paper compliance to defensible compliance. That shift requires more than policies and attestations. It requires continuous, accurate visibility into CUI itself.

A modern approach to cui identification must:

Scan the environment automatically
Identify CUI with precision, not guesswork
Support accurate CMMC scoping
Continuously monitor for change

Solutions like Teramis exist because the problem has outgrown manual processes and generic security tools. When CUI identification becomes automated and continuous, compliance stops being reactive and starts becoming operational.

And in today’s regulatory environment, that difference matters.