For many defense contractors, cybersecurity compliance has long been treated as a process of preparation and documentation. Companies reviewed NIST SP 800-171, implemented the safeguards they believed applied to their networks, completed internal assessments, and assumed they were moving in the right direction.
As CMMC requirements begin appearing in Department of Defense contracts, contractors are discovering that meeting the framework is not simply a matter of having security tools in place. Organizations must be able to demonstrate, with documentation and technical evidence, how their systems protect Controlled Unclassified Information and how those protections are consistently enforced.
Proof, Not Assumptions
Under the earlier self-assessment model, organizations interpreted requirements largely within their own environment. Controls were mapped to existing systems and marked as implemented based on internal understanding. In many cases, those judgments were made in good faith and reflected the organization’s best interpretation of the requirement.
CMMC introduces different expectations. Safeguards must be tied to clearly defined system boundaries, supported by policies that reflect actual operating practices, and backed by evidence that can be reviewed during an assessment. Configuration settings, access management practices, audit logs, training records, and system documentation all become part of the evaluation.
Organizations that begin preparing for certification often discover that the difficulty is not a lack of security capability. It is the challenge of explaining and documenting how their systems are structured.
The Boundary Problem
Many defense contractors operate networks that evolved over the years to support engineering teams, production systems, suppliers, and customer programs. Legacy servers sit alongside cloud platforms. Manufacturing equipment communicates with corporate systems. External partners access shared collaboration tools.
Once Controlled Unclassified Information is introduced into that environment, identifying exactly where it resides and which systems are responsible for protecting it can require a much deeper review than many organizations expect.
Establishing a defensible CMMC boundary means mapping how sensitive data moves through the business, identifying the systems that store or process it, and documenting who is responsible for each layer of protection.
In environments that grew organically, those answers are not always immediately clear. Documentation may not reflect current operations. Responsibilities may be split between internal teams and service providers without clear ownership. Evidence demonstrating how safeguards operate may exist across multiple systems rather than in a single coherent record.
These issues often become visible only when organizations begin preparing for a formal assessment. Controls that appear straightforward in a policy document can become harder to demonstrate when assessors begin reviewing how systems actually operate.
The timing of the CMMC rollout adds additional pressure. As of November 2025, new Department of Defense contracts require contractors to submit self-assessment scores through the Supplier Performance Risk System (SPRS). For companies handling Controlled Unclassified Information, those scores become part of the contracting decision.
In November 2026, third-party certification through a Certified Third-Party Assessment Organization (C3PAO) begins for selected programs. Program offices have the authority to require certification earlier, depending on the sensitivity of the contract or the data involved.
Certification expectations expand further in 2027 when option periods and renewals begin incorporating CMMC requirements. By 2028, the framework is expected to apply broadly across applicable Department of Defense solicitations and contracts.
Enforcement Is Already Changing Behavior
Although the timeline spans several years, prime contractors are already evaluating supplier readiness. When certification requirements apply to a prime contract, those obligations extend throughout the supply chain. Subcontractors that cannot demonstrate progress toward certification may face additional scrutiny during onboarding or find themselves competing with suppliers that are further along in preparation.
Even companies that move early encounter another challenge: assessment capacity.
Tens of thousands of organizations across the defense industrial base are expected to pursue Level 2 certification, while the number of accredited C3PAO assessment organizations remains limited. As more contractors enter the certification pipeline, scheduling assessments becomes an important part of planning.
Organizations that begin preparation earlier typically have time to review system boundaries, update documentation, remediate gaps, and assemble the evidence required for certification. Contractors who delay preparation may find themselves addressing those issues while also competing for available assessment windows.
The transition to CMMC does not introduce entirely new cybersecurity principles. Many of the expectations have existed for years through NIST SP 800-171. The difference lies in how those expectations are evaluated.
Readiness Must Be Demonstrated
Organizations are no longer being asked whether they believe they meet the requirements. They must demonstrate how their systems protect controlled data and provide evidence that those protections operate consistently.
Contractors that take the time to organize their systems, documentation, and processes around that expectation are likely to move through certification with fewer surprises. Those who postpone preparation may find that the greatest challenge is not implementing safeguards, but demonstrating how those safeguards function when formal review begins.
About the Author
Charlie Sciuto, CISO and CTO for SSE, Inc., a Registered Provider Organization (RPO) accredited by the Cyber AB (formerly CMMC Accreditation Body) to help companies prepare for CMMC certification. This can include a readiness assessment, gap assessments, remediation, and continuous monitoring for ongoing compliance.
Charlie can be reached online on LinkedIn and at our company website https://www.sseinc.com/
