CMMC Level 3 Expert Compliance
Last reviewed · By Chad Griffith
CMMC Level 3 Expert applies to defense contractors handling the highest-priority Controlled Unclassified Information — typically advanced technology, weapons systems data, and highly sensitive defense information. Level 3 requires implementation of all 110 NIST SP 800-171 r2 controls plus a subset of NIST SP 800-172 enhanced controls designed to protect against Advanced Persistent Threats (APTs). Assessment is performed by the Defense Industrial Base Cybersecurity Assessment Center (DIBCAC), the DoD's government assessment organization.
Who Needs CMMC Level 3
Level 3 applies to a small number of defense contractors handling the highest-priority CUI. The DoD identifies specific contracts requiring Level 3 certification based on data sensitivity. Common candidates: prime contractors on weapons system programs, advanced technology developers, and contractors handling highly classified-adjacent technical data. The DoD estimates approximately 1,500 contractors will require Level 3 certification.
NIST SP 800-172 Enhanced Controls
NIST SP 800-172 ('Enhanced Security Requirements for Protecting Controlled Unclassified Information') provides 35 enhanced security requirements designed to protect against Advanced Persistent Threats. The DoD has identified a subset of these requirements as the basis for CMMC Level 3 — typically 24+ enhanced requirements layered on top of the 110 NIST 800-171 r2 controls already required at Level 2.
DIBCAC Assessment
The Defense Industrial Base Cybersecurity Assessment Center (DIBCAC) is the DoD's government assessment organization for Level 3 certifications. DIBCAC conducts on-site assessments using a Government-Owned-Contractor-Operated (GOCO) approach. Assessments typically span 2-3 weeks and include extensive evidence review, technical testing, and interviews. Re-assessments occur every three years.
Advanced Persistent Threat Defense
Level 3 controls focus on detecting, responding to, and recovering from sophisticated nation-state-level cyberattacks. Key capability areas: real-time security monitoring with threat hunting, deception technologies, supply chain risk management beyond Level 2 requirements, mandatory red team exercises, advanced incident response capabilities, and dual authentication for the most sensitive operations.
Frequently Asked Questions
Why is Level 3 assessed by DIBCAC and not C3PAOs?
DIBCAC government assessment was retained for Level 3 because the highest-priority CUI sometimes includes information adjacent to classified material. Government assessment ensures assessor security clearance compatibility and consistency in evaluation of the most sensitive contractor environments. The DoD prioritized C3PAO scaling for Level 2 (the larger contractor population) while keeping DIBCAC for Level 3.
How many contractors need Level 3?
DoD estimates approximately 1,500 contractors will require Level 3 certification — a small fraction of the estimated 80,000+ Level 2 contractors. Level 3 is reserved for contracts involving the most sensitive CUI: advanced technology programs, weapons systems data, and similar high-priority categories.
What is NIST SP 800-172?
NIST Special Publication 800-172 is titled 'Enhanced Security Requirements for Protecting Controlled Unclassified Information.' It provides 35 enhanced security requirements designed to protect against Advanced Persistent Threats — sophisticated, often nation-state-affiliated cyberattacks. The DoD selected a subset of these requirements as the basis for CMMC Level 3.
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