What Is a CMMC Enclave? When to Build One and When to Buy One

Quick Answer: A CMMC enclave is an isolated IT environment where Controlled Unclassified Information is stored and processed, letting DoD contractors scope CMMC Level 2 compliance to that boundary instead of the entire organization. Building internally or using a managed provider depends on staffing, timeline, and how close you are to meeting the 110 NIST SP 800-171 controls.

Most DoD contractors don’t need to make their entire IT environment compliant. They need to secure the right part of it, and that’s where a CMMC enclave makes the difference.

By defining a focused compliance boundary around CUI systems and users, a CMMC enclave reduces cost, complexity, and time to certification. For contractors facing Level 2 deadlines in 2026, it can be the difference between getting certified or losing contract eligibility.

Key Takeaways

• CMMC enclave isolates CUI-handling systems into a defined boundary, reducing the number of assets and users subject to compliance controls.
• Scope reduction is the primary financial lever: fewer in-scope assets mean lower assessment costs, less infrastructure to secure, and fewer training requirements. The CMMC Level 2 scoping guide published by the DoD gives contractors a clear framework for making this determination.
• Building an enclave internally requires dedicated IT and security expertise, plus significant ongoing maintenance. Most SMBs underestimate this at $84K to $132K for compliance staffing alone.
• Microsoft 365 GCC High is required for CUI handling in cloud environments. Commercial M365 licenses do not meet CMMC Level 2 requirements.
• A managed compliance partner like BEMO owns the enclave implementation from gap assessment through audit coordination, cutting months off typical certification timelines.

What Is a CMMC Enclave?

An enclave is a set of system resources that operate under a single security policy and are controlled by a single authority. In practical terms, it is the segmented portion of your IT environment where CUI is stored, processed, or transmitted, and where CMMC controls are enforced.

Think of it as a secured room inside a larger building. The entire building does not need vault-level security, only the room holding sensitive materials does. Everything outside that room operates under your standard IT policies. The enclave operates under a separate, stricter set of controls that map directly to CMMC Level 2's 110 security requirements from NIST SP 800-171.

Who and What Falls Inside the Boundary

The enclave includes both technical assets and the people authorized to access them. If a project manager has CUI on her laptop and accesses a compliant file-sharing environment, both that laptop and that user fall inside the compliance boundary.

The goal is to keep that group as small as operationally possible, because every person and device added to the secure enclave for CMMC increases implementation scope, assessment time, and cost.

For U.S.-based contractors with under 500 employees handling DoD CUI, the enclave model is typically the most realistic path to Level 2 certification. As the BEMO compliance team works with clients on their CMMC requirements, scoping the enclave correctly is consistently the first and most consequential decision in the certification process.

A CMMC enclave is often positioned as a way to reduce compliance scope, but it is not a shortcut. It only works when it is properly scoped, fully documented, and implemented against controls that can withstand a C3PAO assessment.

How a CMMC Enclave Reduces Compliance Costs

CMMC costs scale with your compliance boundary. A well-designed enclave keeps scope tight, reducing assessment effort, training, and overall certification spend.

Scope Drives Every Cost Line

CMMC assessment costs increase with scope. More assets, users, and systems mean more evidence, more controls, and longer C3PAO evaluations. Level 2 assessments can exceed $50,000 and rise with each additional endpoint.

A CMMC secure enclave limits that scope. Instead of covering an entire organization, you isolate only CUI users and systems. Fewer endpoints mean less infrastructure to assess and less documentation to maintain.

Training and Operational Overhead

Scope reduction also lowers training overhead. Under CMMC Level 2, every in-scope user requires documented training and must follow strict access controls.

Keeping the user group limited ensures training aligns with actual CUI access, rather than becoming an organization-wide burden that pulls time from every department.

First-Time Certification Reality

For first-time certification, enclave architecture significantly reduces cost. Many contractors initially treat their entire Microsoft 365 environment as in-scope.

Defining a clear enclave with segmented access and CUI-specific controls makes CMMC Level 2 achievable without the cost of enterprise-wide compliance.

When to Build a CMMC Enclave vs. Buy a Managed Solution

The architecture decision and the delivery model are separate questions. You might build your own CMMC secure enclave, or you might purchase access to a pre-configured, managed enclave environment. The right choice depends on your internal resources, timeline, and risk tolerance.

Build vs. Managed Secure Enclave for CMMC: At a Glance

Build Your Own CMMC Enclave

Building internally gives you full control, but it also places the entire compliance burden on your team.

When Building Internally Makes Sense

Building internally fits larger defense contractors with dedicated security teams, existing infrastructure to preserve, and the capacity to maintain an ISMS. If you already have a compliance lead, active security operations, and can absorb a long timeline without impacting contracts, it’s a viable path.

Why It Becomes a Process Problem

The challenge is not technology, it’s process. You must map all 110 NIST SP 800-171 controls, implement solutions, produce a System Security Plan, run gap assessments, and maintain audit-ready evidence for C3PAO review.

The Real Cost of Internal Builds

Without existing compliance infrastructure, this typically means a dedicated hire at $84,000 to $132,000 annually, plus hiring and onboarding time. For teams using external managed IT support, compliance often competes directly with daily operations unless fully resourced.

Partner with a Managed Compliance Provider

For most organizations, handing off the complexity to a dedicated partner reduces risk and accelerates timelines.

Why Managed Enclaves Are More Efficient

For most DoD contractors with under 500 employees, a managed enclave solution is faster, lower-risk, and ultimately less expensive than building internally. This is especially true for companies that have tried DIY compliance and stalled, teams under contract-deadline pressure, or organizations handling CUI across multiple frameworks simultaneously.

The Complexity of Multi-Framework Compliance

The overlap between CMMC, SOC 2, and ISO 27001 controls creates mapping complexity that software tools alone cannot resolve. The build vs managed secure enclave CMMC decision often comes down to one question: does your organization have the people and time to own this process internally, or does it need a partner who can take it off your plate?

How BEMO Handles the Outcome

BEMO's approach to managed compliance is built around owning the outcome, not just providing tooling. A dedicated Compliance Engineer handles gap assessments, control implementation, SSP documentation, and auditor coordination.

Evidence collection is automated where possible and validated before it reaches a C3PAO. Organizations that partner with BEMO's compliance team skip the six-month staffing ramp and move from assessment to certification on a compressed timeline.

Deciding between building or using a managed enclave? Speak with us to evaluate the fastest path to certification.

How to Create a CMMC Enclave

Creating a compliant enclave involves five sequential workstreams, each building on the last. Skipping steps or running them in parallel is a common reason DIY implementations fail audits.

Step 1: Define Your CUI Scope

Start by identifying where CUI exists across your environment, including storage, processing, and transmission points. Not every employee needs access. Limiting users reduces your compliance boundary and makes your CMMC secure enclave easier to manage. Follow the CMMC level 2 scoping guide to classify in-scope assets.

Step 2: Establish Your Compliance Boundary

With scope defined, create a clear boundary using physical or logical separation. Logical separation requires more than VLANs. You also need separate credentials, authentication, and enforceable access controls that meet C3PAO expectations. Network segmentation alone will not pass assessment.

Step 3: Implement Required Security Controls

Email and file sharing are the highest-risk CUI surfaces. Standard Microsoft 365 environments are not authorized. CMMC Level 2 requires Microsoft 365 GCC High to meet FedRAMP, DFARS 7012, and FIPS requirements. Controls must also cover access, endpoints, logging, vulnerability management, and incident response.

Each control must be documented, configured, and demonstrable, not just described in policy language. BEMO's Platinum Security stack is built to satisfy these controls in Microsoft 365 GCC High environments with minimal configuration burden on the contractor's internal team.

Step 4: Create Policies and Procedures

Technology alone is not enough. Policies define how CUI is handled, accessed, and secured. CMMC Level 2 requires 18+ policies covering areas like access control, incident response, and configuration management.

These must be current, reviewed regularly, and acknowledged by users. Training tied to these policies is critical. Treating policies as static documents is a common failure point in DIY programs.

Step 5: Conduct a Gap Assessment

Before a C3PAO audit, run a gap assessment against all 110 NIST SP 800-171 controls. This generates your SPRS score and identifies remediation needs.

Skipping this step often leads to delays. When submitting to SPRS, select “Enclave” if your boundary is scoped, as this affects how your compliance posture is evaluated.

Book a call with BEMO to start your gap assessment

CMMC Enclave Scoping: Defining Your Compliance Boundary

Your CMMC enclave is only as effective as the boundary you define. Getting scoping right determines what must be secured, what stays out of scope, and how much your certification will ultimately cost.

Why Scope Is the Most Consequential Variable

Scope drives everything in CMMC Level 2. Too narrow leaves gaps that fail assessment. Too broad increases cost with no benefit.

The DoD scoping guide defines asset categories. CUI and security protection assets are in-scope, while contractor risk managed assets require documented risk analysis.

The Three-Step Scoping Process

Follow a structured approach: identify CUI-related assets, categorize them per the DoD framework, then define and enforce the boundary.

Any system that can reach CUI is in-scope unless separation is proven. This is where many teams underestimate scope and face issues during assessment.

Scope Reduction as a Cost Control Strategy

Tighter scope directly reduces cost. Limiting an enclave to 20 endpoints instead of 200 reduces assessment time, evidence requirements, and ongoing maintenance compared to enterprise-wide compliance.

Every line item in your CMMC certification budget, from assessment fees to infrastructure upgrades to documentation overhead, scales with the number of in-scope assets. A clear understanding of CMMC certification costs starts with a clear understanding of how scope drives those costs.

Key Questions to Ask During CMMC Enclave Scoping

Which employees or contractors have any access to CUI, directly or indirectly?

• Which systems store, process, or transmit CUI, including cloud environments, shared drives, and email?
• Which systems protect CUI assets, such as firewalls, identity providers, MFA infrastructure, and log aggregators?
• Which systems are interconnected with CUI-handling systems and therefore inherit in-scope status under the CMMC scoping guide?
• Can any out-of-scope systems reach CUI through a network path, and if so, is that path enforced shut?
• Is your cloud environment authorized for CUI handling, or does it require migration to GCC High?

Simplify CMMC Compliance with BEMO

For DoD contractors trying to hit Level 2 certification without a dedicated compliance team, the enclave model works, but only if it is scoped correctly, documented thoroughly, and implemented against controls that will hold up to C3PAO review.

DIY compliance programs most commonly fail at three points:

1. They undercount in-scope assets during scoping
2. They treat documentation as a one-time task rather than a continuous process
3. They discover control gaps during formal assessment rather than before it.

By that point, remediation delays certification and, in some cases, affects contract eligibility.

BEMO's managed compliance service handles the entire workstream. From your initial gap assessment through GCC High migration, control implementation, SSP documentation, and auditor coordination, BEMO owns the process so your internal team does not have to.

With a dedicated Compliance Engineer assigned to your account and a 72-hour remediation SLA, you get a defined path to certification rather than a software dashboard that identifies problems and leaves you to solve them.

Ready to define your secure enclave for CMMC and get compliant before your next contract deadline? Book a call with BEMO and start with a structured gap assessment.

Frequently Asked Questions

What is a secure enclave for CMMC?

A secure enclave for CMMC is an isolated IT environment, physical or logical, where all CUI is stored, processed, and transmitted, and where CMMC security controls are enforced. It includes both the technical assets and the authorized users who access CUI within that boundary. Contractors use it to limit CMMC compliance scope to the portion of their IT environment that actually handles controlled information, rather than applying all 110 controls organization-wide.

How does a CMMC enclave align with CMMC 2.0 requirements?

CMMC 2.0 Level 2 requires compliance with 110 controls from NIST SP 800-171, and those controls apply to in-scope assets within your defined enclave boundary. The DoD's CMMC level 2 scoping guide published alongside CMMC 2.0 explicitly recognizes the enclave model, and SPRS reporting includes an 'Enclave' entry option.

CMMC enclave vs. enterprise-wide compliance: which is better?

For most small to mid-sized defense contractors, enclave-scoped compliance is more achievable and cost-effective than enterprise-wide compliance. Enterprise-wide models apply controls across all systems and users, which suits large primes but is expensive for lean teams. An enclave approach achieves Level 2 certification by securing only the CUI environment.

Can I use Microsoft 365 in a CMMC enclave?

Yes, but not with a standard commercial Microsoft 365 subscription. CMMC Level 2 requires that cloud environments handling CUI meet FedRAMP High authorization and FIPS 140-3 encryption standards, which commercial M365 does not satisfy. Microsoft 365 GCC High is the correct licensing tier for a secure enclave for CMMC, and migrating to GCC High is one of the most consistently underestimated implementation tasks in DIY compliance programs.