If you’re a defense contractor preparing for CMMC 2.0 certification, outsourcing your compliance efforts might seem like the most practical solution. Requirements are complex, the stakes are high, and many small and mid-sized businesses lack the internal resources to manage it all.

Limited budgets, technical complexity, and confusion about how to operationalize the requirements continue to delay CMMC readiness across the DIB. A 2024 survey by Redspin found that more than half of defense contractors were unprepared for the Final Rule, and a follow-up study by Kiteworks and Coalfire reported that only 46% of contractors in the defense industrial base (DIB) feel ready for Level 2 certification. It’s no surprise that many contractors are turning to external service providers for help.

But it’s not that simple. During its April 2025 Town Hall, the Cyber AB made one thing clear: CMMC compliance cannot be outsourced.

That doesn’t mean you have to do it all alone. The right Managed Service Provider (MSP), Managed Security Service Provider (MSSP), or External Service Provider (ESP) can play a valuable role in helping you close identified gaps, implement technical controls, and prepare for an assessment. But there are firm boundaries around what they can and can’t do.

Below, we’ll break down the boundaries between what service providers can and can’t do, and explain how to work with one in a way that supports your compliance without creating a false sense of security.

Service providers can support compliance, not take it on

During its April 2025 Town Hall, the Cyber AB addressed a growing source of confusion within the CMMC ecosystem: the role of MSPs, MSSPs, and other ESPs in helping clients achieve compliance.

Their message was very clear. The Organization Seeking Certification (OSC) is ultimately accountable for all 110 requirements and 320 assessment objectives under CMMC Level 2. That responsibility cannot be transferred, delegated, or outsourced. 

Service providers can support CMMC compliance, but they cannot fulfill compliance obligations on behalf of their clients. If a compliance gap is discovered, it is your organization that will be held accountable, not your provider.

What MSPs, MSSPs, and ESPs can do

That doesn’t mean you’re on your own. A skilled service provider can be an important partner in your compliance journey.

An MSP or MSSP can help implement essential security tools and technologies, such as firewalls, endpoint protection software, and access controls that align with NIST 800-171 requirements. They can also develop and manage your cloud environment or secure enclave where Controlled Unclassified Information (CUI) is processed, stored, or transmitted, ensuring those systems remain secure and properly configured.

Ongoing monitoring is another key area where service providers can add value. They can monitor your systems for unusual activity, detect threats, and alert your team to potential vulnerabilities. Many also provide hands-on support with incident response planning and execution, helping your organization quickly recover in the event of a breach or security incident.

In addition to technical support, MSPs and MSSPs can assist with the extensive documentation required for CMMC 2.0 compliance. They can help collect system logs, diagrams, and other artifacts that may be needed during an assessment. While they cannot complete this documentation for you, they can offer guidance and assist with compiling and organizing the necessary evidence.

Finally, a provider may offer input on your System Security Plan (SSP), document control implementations, and help keep it updated as your environment changes. Although they can’t take ownership of this critical document, they can help ensure that the technical portions they support are accurately reflected.

These services are essential to building and maintaining a strong security program, and an ESP can help with some of the manual work required. However, they are support functions and not a replacement for internal responsibility. Your organization still owns the overall compliance effort.

What service providers can’t do

This is where many organizations get confused. Your service provider cannot speak for your organization during an assessment or make foundational security decisions on your behalf.

According to the Cyber AB, a service provider cannot assume ownership of your System Security Plan. They also cannot offer pre-filled Customer Responsibility Matrices (CRMs) and claim those documents cover everything without customization or input from your internal leadership.

Decisions about your authorized users, the boundaries of your system, and how access is controlled are business decisions that must come from within your organization. While your provider can help enforce and maintain those decisions through technical means, they cannot define them for you.

Service providers also cannot serve as your representative during an assessment. The responsibility to demonstrate compliance rests with your internal team, and assessors will expect to speak with the people who make the decisions and oversee the processes.

Perhaps most importantly, a provider cannot shield you from the need to maintain internal processes and oversight. CMMC compliance is not a one-time technical deployment — it’s an ongoing commitment. If the activity involves policy, management judgment, or ownership of CUI, it is ultimately your responsibility to ensure it’s addressed.

Some ESPs are pursuing their own CMMC certifications, and a certified ESP may reduce the scope or rigor of your assessment if they are managing specific components of your environment, particularly those related to the storage or transmission of CUI.

However, this does not mean your organization is covered simply because your provider has achieved certification. You are still required to meet every CMMC requirement relevant to your own environment, policies, and practices. The presence of a certified provider in your supply chain may reduce some complexity, but it does not eliminate your compliance obligations.

The Customer Shared Responsibility Matrix: An essential tool for clarity and compliance

To clarify what your service provider is doing and what you still need to handle internally, request a Shared Responsibility Matrix (SRM) or Customer Responsibility Matrix (CRM). This document clearly outlines who is responsible for each specific control or security requirement, your organization or your service provider. An SRM/CRM helps prevent confusion during readiness and assessments by clarifying:

• What your MSP, MSSP, or ESP is managing, such as firewalls, monitoring, and cloud infrastructure
• What your organization is still accountable for, such as user access decisions, policy enforcement, and physical security
• Which responsibilities are shared and how they are divided

The most useful SRMs map responsibilities at the level of individual controls or even specific assessment objectives. A high-level mapping that only references broad requirements will likely be insufficient for an actual assessment. Ask your provider to map their services to NIST SP 800-171A, the set of assessment procedures that C3PAOs will use to verify compliance. If your provider can’t show that mapping, you may be missing key elements that are required for your assessment and may not be able to get past phase 1 of a CMMC audit.

Be cautious if a provider claims they determine authorized users for your organization or promises a fully managed solution that requires no effort on your part. These are warning signs that they may not fully understand or may be misrepresenting the boundaries of their role. If they give you a CRM for your environment that is fully pre-filled without any input from your team or of your environment, that’s another red flag.

Treat service providers as partners, not proxies 

CMMC 2.0 was created to ensure that every organization in the defense supply chain takes ownership of its security responsibilities. That means your company — not your MSP or MSSP — is ultimately responsible for protecting sensitive information and proving that your environment meets the standard.

If your organization has not been actively involved in the compliance process, you may discover during an assessment that key requirements were overlooked or not fully implemented. At that point, it may be too late to address the issues without delaying your certification.

A trusted service provider or consultant can help you manage systems, enforce policies, and prepare for audits. They can make the path to compliance clearer and more efficient. But they cannot walk the path for you.

The companies that succeed with CMMC are the ones that take an active role in the process. They treat their providers as partners, not substitutes. They understand the importance of maintaining internal oversight, staying involved in decision-making, and creating a security-first culture.