CMMC-AB plays a central role in how organizations achieve compliance with the Cybersecurity Maturity Model Certification (CMMC), the Department of Defense’s framework for protecting Controlled Unclassified Information (CUI).
CMMC will be required for organizations that contract with the U.S. Department of Defense (DoD). While these contracts can be highly valuable, they require meeting strict cybersecurity standards. To achieve certification, organizations must be assessed by a qualified third-party assessor that is accredited by the CMMC Accreditation Body (CMMC-AB).
In this article, we explain who the CMMC-AB is, what it does, and how it fits into the broader CMMC ecosystem, including the other key stakeholders responsible for enforcing and maintaining CMMC requirements.
What Is the CMMC-AB and What Do They Do?
The CMMC Accreditation Body (CMMC-AB) is responsible for overseeing the training, accreditation, and quality assurance of professionals and organizations involved in the Cybersecurity Maturity Model Certification (CMMC) program.
Any organization working with the U.S. Department of Defense (DoD) is entrusted with protecting sensitive government information. Because this data directly impacts military operations and national security, basic cybersecurity controls are not sufficient. CMMC certification establishes a formal, standardized framework to ensure contractors meet consistent security requirements.
This guide explains who the CMMC-AB is, what it does, and how it interacts with other CMMC stakeholders, including:
- What the CMMC-AB is and how it relates to assessors, the DoD, and other governing bodies
- What CMMC is and what full CMMC compliance includes
By the end of this article, you’ll understand who to work with to begin or complete your CMMC certification journey, and how RSI Security can help guide you through the process
Understanding the Responsibilities of the CMMC-AB
The CMMC Accreditation Body (CMMC-AB) is responsible for accrediting and overseeing the third-party organizations that assess contractors for compliance with the Cybersecurity Maturity Model Certification (CMMC). Operating as a nonprofit organization headquartered in Maryland, the CMMC-AB was established in January 2020 to support the implementation and scalability of the CMMC program.
One of the CMMC-AB’s primary responsibilities is accrediting qualified assessment organizations, ensuring they meet the standards required to evaluate CMMC compliance accurately and consistently. Through this role, the CMMC-AB helps connect organizations seeking CMMC certification with approved assessors.
The CMMC-AB offers multiple levels of assessor accreditation. The most critical designation in the current CMMC framework is the Certified Third-Party Assessor Organization (C3PAO). To become a C3PAO, organizations must meet strict eligibility requirements, including:
- Demonstrating compliance with applicable CMMC requirements
- Maintaining full ownership by U.S. citizens
- Carrying appropriate insurance coverage
- Entering into a licensing agreement with the CMMC-AB
In addition to accreditation, the CMMC-AB maintains an official registry of authorized C3PAOs, enabling organizations pursuing CMMC certification to identify and engage assessors that align with their scope, budget, and compliance needs.
The Roles of Other DoD and DoD-Adjacent Stakeholders
While the CMMC Accreditation Body (CMMC-AB) manages assessor accreditation, overall authority for the CMMC program rests with the Office of the Under Secretary of Defense for Acquisition and Sustainment (OUSD-A&S). OUSD-A&S oversees CMMC policy and implementation to ensure secure, efficient acquisition across the U.S. Department of Defense (DoD) and the Defense Industrial Base (DIB).
Beyond the DoD and CMMC-AB, several DoD-adjacent organizations play critical roles in shaping the standards that underpin CMMC requirements. These stakeholders include the entities responsible for federal acquisition rules and cybersecurity control frameworks, such as:
- Federal Acquisition Regulation (FAR) and the Defense Federal Acquisition Regulation Supplement (DFARS), which govern contractual cybersecurity requirements for DoD contractors and are codified in the Code of Federal Regulations (CFR) and published by the Office of the Federal Register (OFR)
- NIST Special Publication 800-171, Protecting Controlled Unclassified Information in Nonfederal Systems and Organizations, along with related supplemental guidance published by the National Institute of Standards and Technology (NIST)
These organizations, particularly OFR and NIST, are staffed by subject-matter experts across cybersecurity, IT, and risk management disciplines. Their work establishes the regulatory and technical foundation that informs CMMC requirements and enables consistent enforcement across the defense supply chain.
Understanding Compliance with the CMMC Framework
When your organization is assessed by a Certified Third-Party Assessor Organization (C3PAO) or another assessor accredited by the CMMC Accreditation Body (CMMC-AB), certification is directly tied to how well your company implements the CMMC framework. This framework is based on cybersecurity standards from NIST and other federal agencies, making it a rigorous yet accessible path to compliance.
The CMMC framework is organized into five Maturity Levels, which allow organizations to adopt cybersecurity controls gradually:
- Maturity Levels
- Each level builds on the previous, enabling stepwise adoption of controls.
- Assessments test your company’s implementation of both practices and process maturity goals at each level.
- Domains, Capabilities, and Practices
- The CMMC framework includes 17 domains, covering key cybersecurity areas.
- These domains are broken down into 43 capabilities and 171 practices, ensuring a comprehensive security posture across all aspects of an organization.
This structure allows organizations to scale their compliance efforts while meeting the standards required to secure contracts with the Department of Defense (DoD).
Breakdown of CMMC Framework Maturity Levels
The CMMC framework is divided into five Maturity Levels, each focusing on specific security goals, practices, and process maturity thresholds. Understanding these levels is essential for companies preparing for CMMC certification through a C3PAO accredited by the CMMC-AB.
| Maturity Level | Security Focus | Practice Goal | Process Maturity |
| Level 1 | Protecting Federal Contract Information (FCI) | Basic cyber hygiene | Performed |
| Level 2 | Preparing for Controlled Unclassified Information (CUI) | Intermediate cyber hygiene | Documented |
| Level 3 | Full-scale protections for FCI and CUI | Good cyber hygiene | Managed |
| Level 4 | Defending against Advanced Persistent Threats (APT) | Proactive practices | Reviewed regularly |
| Level 5 | Optimizing protections for FCI/CUI and APT | Advanced/progressive practices | Continuously optimized |
Key Notes:
- The first three Maturity Levels align directly with current DoD requirements.
- Level 3 incorporates all controls from NIST SP 800-171, along with additional selected requirements.
- Levels 4 and 5 focus on advanced protections and APT mitigation, and their assessment methodologies are still under development.
This tiered approach allows organizations to progressively strengthen cybersecurity practices while achieving measurable compliance milestones.
Breakdown of CMMC Framework Security Domains
The CMMC framework organizes its 171 practices into 17 security domains, each based on requirement families from NIST SP 800-171. Each domain includes a specific number of capabilities and practices, as outlined below:
| Domain (Abbr.) | Capabilities | Practices |
| Access Control (AC) | 4 | 26 |
| Asset Management (AM) | 2 | 2 |
| Audit and Accountability (AU) | 4 | 14 |
| Awareness and Training (AT) | 2 | 5 |
| Configuration Management (CM) | 2 | 11 |
| Identification and Authentication (IA) | 1 | 11 |
| Incident Response (IR) | 5 | 13 |
| Maintenance (MA) | 1 | 6 |
| Media Protection (MP) | 4 | 8 |
| Personnel Security (PS) | 2 | 2 |
| Physical Protection (PE) | 1 | 6 |
| Recovery (RE) | 2 | 4 |
| Risk Management (RM) | 3 | 12 |
| Security Assessment (CA) | 3 | 8 |
| Situational Awareness (SA) | 1 | 3 |
| Systems and Communications Protection (SC) | 2 | 27 |
| System and Information Integrity (SI) | 4 | 13 |
Across all domains, capabilities, and practices, achieving CMMC compliance can be complex. Partnering with a C3PAO accredited by the CMMC-AB, such as RSI Security, simplifies the process and ensures your organization meets the necessary standards for DoD contracts.
Simplify CMMC Compliance with a Quality C3PAO
The CMMC Accreditation Body (CMMC-AB) is primarily responsible for accrediting Certified Third-Party Assessor Organizations (C3PAOs), such as RSI Security. Most companies interact directly with a C3PAO, rather than the CMMC-AB itself.
Not all C3PAOs offer the same level of expertise. At RSI Security, our team guides organizations through every step of CMMC compliance, from initial assessment to implementing required controls. Partnering with a qualified C3PAO ensures your company meets DoD cybersecurity requirements efficiently and accurately.
For tailored solutions to your compliance and cybersecurity needs, Contact RSI Security to get started today.
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