Understanding GCC High and Its Role in CMMC 2.0 Compliance

What’s New (Updated re: Cloud & CUI Requirements)

This blog reflects the CMMC Final Rule (32 CFR Part 170), fully enforceable as of November 10, 2025. Contractors must now meet their required CMMC level at contract award. They must also ensure that cloud environments handling CUI meet FedRAMP Moderate (or equivalent) requirements and maintain accurate SPRS scores. As a result, references to phased or future rollout have been updated to reflect active enforcement across DoD solicitations.

What Is GCC High? Is It Essential for CMMC Compliance?

Microsoft 365 GCC High is a dedicated cloud environment. It is designed to meet the rigorous security and compliance demands of the U.S. government. It provides a secure framework for organizations managing Controlled Unclassified Information (CUI) and pursuing compliance with:

• Defense Federal Acquisition Regulation Supplement (DFARS)
• NIST 800-171
• International Traffic in Arms Regulations (ITAR)
• Cybersecurity Maturity Model Certification (CMMC)

In practice, many organizations, particularly small to medium-sized businesses (SMBs), face challenges due to prohibitive costs and complex infrastructure when establishing a comparable secure environment internally. Additionally, they often struggle with the configuration, management, and maintenance of a compliant cloud platform.

Exostar’s Managed Microsoft 365™ offers a budget-friendly approach to achieving compliance without the financial, technical, and administrative strains.

Benefits of the GCC High Environment

Microsoft 365 GCC High is designed to comply with a variety of government standards, delivering robust data protection, compliance tools, and seamless integration with other Microsoft services.

The primary advantages of the GCC High environment include:

• Comprehensive Compliance: GCC High is built with CMMC compliance as a focal point. It sets the benchmark for meeting U.S. government cybersecurity mandates. It provides extensive protection that aids organizations in meeting NIST SP 800-171, DFARS 252.204-7012, and additional regulations.
• Scalable Solution: The GCC High platform allows businesses to grow in alignment with their operational demands.
• Microsoft Expertise: Organizations utilizing GCC High gain from Microsoft’s technical and regulatory insights, which help maintain security and compliance as regulatory landscapes evolve.

CMMC 2.0 Requirements for DIB Companies

The Cybersecurity Maturity Model Certification (CMMC) is now fully enforceable under the Final Rule. DoD solicitations already include Level 1 and Level 2 requirements at contract award. The DoD published the final CMMC 2.0 rule in the Federal Register in October 2024, with the second part (48 CFR) expected to fully enforce CMMC 2.0 requirements for Department of Defense contracts by early 2025.

Specifically, CMMC 2.0 consists of three levels:

1. Level 1: Involves basic safeguarding practices requiring annual self-assessments to meet 15 requirements aligned with Federal Acquisition Regulation (FAR) 52.204-21.
2. Level 2: Aligns with NIST 800-171 and demands third-party assessments every three years, conducted by CMMC Third Party Assessment Organizations (C3PAOs) accredited by CyberAB.
3. Level 3: Requires Level 2 compliance and adherence to additional controls and regulations from NIST 800-172, alongside assessments managed by the Defense Contract Management Agency (DCMA).

Under the Final Rule, Level 1 and Level 2 requirements are now active, and organizations must meet the level specified in each solicitation at award time. As CMMC becomes fully operational, DoD contracts will require third-party assessments.

Is GCC High Required for CMMC?

A common query among organizations aiming for CMMC compliance is whether GCC High is mandatory. GCC High is not strictly required to achieve CMMC compliance. However, many organizations view it as the optimal environment for managing CUI.

However, creating and sustaining a compliant environment on GCC High can exceed $100,000, making it cost-prohibitive for smaller DIB contractors. Exostar enables smaller organizations to access the benefits of GCC High without the hefty price tag.

Affordable CMMC 2.0 Compliance Solution

Exostar® has crafted a managed solution that leverages GCC High, allowing SMBs to utilize the platform’s advanced features without incurring excessive costs. Exostar Managed Microsoft 365™ for CMMC Compliance enhances identity and access management in the GCC High environment. It provides a secure setting for businesses to store, process, and share CUI.

Exostar designed this solution for companies that lack the internal IT resources needed to meet compliance requirements.

Features of Exostar’s® Managed GCC High Solution – Managed Microsoft 365™

• Federal Standards Compliance: Exostar’s Managed Microsoft 365™ adheres to FedRAMP Moderate Equivalent standards, DFARS requirements, and ITAR, ensuring secure handling and storage of data within the U.S.
• Enhanced Security with Microsoft Services: The managed solution integrates with Microsoft 365 Teams/SharePoint applications, enabling organizations to utilize secure file sharing and collaboration—all within a compliant Software as a Service framework.
• Managed Setup and Simplified Complexity: Exostar’s® technical team oversees the configuration and setup of the GCC High tenant, including user provisioning and multi-factor authentication (MFA) controls, reducing the need for internal tech resources.

SMBs can effortlessly adopt a fully compliant environment without the intricacies associated with infrastructure development.

Manage and Protect Sensitive Information with Exostar®

Exostar’s GCC High™ provides a secure and compliant environment that boosts productivity for organizations handling sensitive information.

SMBs can leverage capabilities typically enjoyed by larger contractors.

• Secure Storage and Collaboration: Users can securely exchange CUI while keeping the data separate from their broader corporate infrastructure, ensuring sensitive data remains isolated from non-secure environments.
• Partner Access: Exostar’s Managed Access Gateway™ enables organizations to confidently and securely integrate partners into the GCC High environment with MFA credentials, fostering swift onboarding and secure collaboration among organizations in the DIB.
• Scalability for All Sizes: Exostar Managed 365™ is flexible enough to accommodate both small enterprises and larger corporations.

An Affordable Route to Compliance

Navigating the complexities of U.S. government cybersecurity compliance can be overwhelming, particularly for small to medium-sized businesses. Exostar® offers a viable and scalable solution for organizations in the Defense Industrial Base that need a secure, compliant, and cost-effective means to manage CUI.

If your organization struggles with securing CUI in the cloud or maintaining compliance across collaboration workflows, now is the time to modernize your approach. Explore managed solutions that help defense contractors streamline secure access, align with NIST SP 800-171, and prepare for Level 1 and Level 2 requirements under the Final Rule.

Find out how Exostar’s Managed Microsoft 365™ can streamline your CMMC compliance efforts. Talk to sales.

What You Should Do Now

To comply with the Final Rule, organizations must confirm whether their upcoming solicitations require Level 1 or Level 2 certification, validate that any environment handling CUI meets FedRAMP Moderate (or equivalent) standards, and ensure access control, evidence documentation, and collaboration workflows align with NIST SP 800-171. Evaluate your current cloud tools, confirm SPRS score accuracy, and determine whether your Level 2 requirement calls for a self-assessment or a C3PAO review.