The cybersecurity landscape for the Defense Industrial Base (DIB) is defined by two major acronyms: NIST and CMMC. While they are often discussed together, they serve distinctly different purposes. NIST provides the what (the security requirements), and CMMC provides the how (the verification and certification process).
NIST SP 800-171 currently exists in multiple revisions. While Revision 3 is the most current publication, the Department of Defense (DoD) has formally based CMMC Level 2 requirements on NIST SP 800-171 Revision 2. Organizations pursuing CMMC Level 2 certification must demonstrate compliance with Revision 2, not Revision 3, unless and until the DoD updates the CMMC rulemaking to reference a newer revision.
Understanding this relationship is crucial for any contractor or subcontractor handling sensitive government information.
The Foundation: NIST SP 800-171
The journey to compliance for DoD contractors begins with a specific publication from the National Institute of Standards and Technology (NIST): Special Publication (SP) 800-171.
If you need a complete overview of the agency, start with our article: What is NIST?
What is NIST SP 800-171?
- Definition: NIST SP 800-171 is a set of 110 security requirements designed to protect the confidentiality of Controlled Unclassified Information (CUI) when it resides on non-federal information systems (i.e., on a contractor’s own network).
- Purpose: It was designed to provide a baseline set of controls based on the exhaustive security catalog in NIST SP 800-53, tailored specifically for the private sector that handles CUI.
- Verification (Pre-CMMC): Historically, compliance with NIST SP 800-171 was largely based on a self-assessment model. Contractors were required to document their compliance in a System Security Plan (SSP) and report their score to the DoD’s Supplier Performance Risk System (SPRS).
In short, NIST SP 800-171 is the security blueprint that specifies what security controls must be implemented.
The Enforcer: Cybersecurity Maturity Model Certification (CMMC 2.0)
The DoD introduced CMMC to address a systemic problem: the low compliance rate and inconsistent self-reporting under the old NIST SP 800-171 self-assessment model. CMMC is the DoD’s verification program.
If you need a complete overview of the program, start with our article: Understanding CMMC and Its Critical Deadlines
What is CMMC?
- Definition: CMMC is a tiered cybersecurity program designed to verify and certify that contractors and subcontractors across the DIB have implemented the required security practices at the appropriate maturity level.
- Mandate: CMMC is mandatory for all DoD contractors handling Federal Contract Information (FCI) or Controlled Unclassified Information (CUI) and will be specified as a condition of contract award.
- Verification (Post-CMMC): CMMC shifts the paradigm from self-assessment to third-party validation for contracts involving sensitive CUI.
In short, CMMC is the certification process that verifies how well the NIST controls have been implemented and institutionalized.
Key Differences: NIST SP 800-171 vs. CMMC 2.0
While CMMC Level 2 is built directly upon the 110 requirements of NIST SP 800-171, its core functions and compliance mechanisms differ significantly.
| Feature | NIST SP 800-171 (The Standard) | CMMC 2.0 (The Program) |
| Primary Goal | Defines what security controls are required for CUI. | Verifies the extent to which those controls are implemented. |
| Structure | A single set of 110 requirements across 14 families. | A tiered maturity model with 3 levels. |
| Verification | Primarily Self-Assessment (reporting score to SPRS). | Required Third-Party Assessment (for critical CUI) or self-assessment (for less sensitive CUI). |
| Maturity | Focuses on the implementation of controls (pass/fail). | Requires evidence of maturity and institutionalized processes. |
| POA&M | Allowed and widely used to document security gaps. | Limited allowance for Plan of Action & Milestones (POA&Ms); high-priority controls must be fully met before certification. |
While some organizations are told they must be ‘NIST compliant,’ it is critical to confirm which revision is contractually required. CMMC Level 2 explicitly maps to NIST SP 800-171 Revision 2, not the newer Revision 3.
The CMMC 2.0-Tiered Structure
CMMC aligns with NIST standards across its three levels:
| CMMC Level | Data Handled | Security Requirements | Assessment Requirement |
| Level 1 (Foundational) | FCI (Federal Contract Information) | 15 basic security practices (from FAR 52.204-21). | Annual Self-Assessment. |
| Level 2 (Advanced) | CUI (Controlled Unclassified Information) | 110 requirements from NIST SP 800-171. | Triennial Third-Party Assessment (C3PAO) or Self-Assessment (depending on contract). |
| Level 3 (Expert) | Critical CUI and high-risk programs | 110 NIST SP 800-171 controls + 24 enhanced controls from NIST SP 800-172. | Triennial Government-Led Assessment. |
The Takeaway: They Are Interdependent
The most important concept to grasp is that CMMC does not replace NIST SP 800-171; it enforces it.
- NIST SP 800-171 is the mandatory benchmark. You cannot achieve CMMC Level 2 without meeting all 110 requirements of NIST SP 800-171.
- CMMC is the required gatekeeper. It ensures that the required NIST controls are not just documented on paper but are actively implemented, documented, and verified by an objective, certified assessor.
NIST SP 800-171 Revision 2 is the mandatory benchmark for achieving CMMC Level 2 today. Organizations cannot achieve CMMC Level 2 certification without meeting all 110 Revision 2 requirements.
For any organization in the defense supply chain, the immediate priority is to achieve and maintain full compliance with NIST SP 800-171. Once that foundation is solid, preparing for the formal CMMC audit becomes the final, essential step to securing DoD contracts.
Partnering for Security and the Future of Standards
The path to CMMC compliance requires rigorous planning, detailed documentation, and readiness for a potential third-party audit. Don’t navigate the complexities of federal compliance and advanced security standards on your own.
Our team of certified NIST and CMMC professionals specializes in bridging the gap between the NIST requirements and the CMMC verification process.
