Migration to M365 GCC High

Published on February 15, 2025

What is GCC High?

Microsoft 365 GCC High is a DoD cloud environment for DoD personnel, federal agencies, and cleared contractors. It meets FedRAMP High requirements and runs on Azure Government for enhanced security. Available only to U.S.-based organizations that meet strict eligibility criteria, it ensures ITAR-compliant data residency with U.S.-only data centers, directory services, and processing.

Why Move to GCC High?

For DoD contractors handling Controlled Unclassified Information (CUI), migrating to Microsoft 365 GCC High is a step toward meeting CMMC 2.0 requirements. Here’s a tactical roadmap to streamline your compliance journey.

Why is GCC High needed for CMMC 2.0 Compliance?
  • Sovereign Cloud: Hosted in U.S. data centers with FedRAMP High, DFARS 7012, and ITAR compliance
  • Preconfigured Controls: Aligns with 93/110 NIST SP 800-171 controls required for CMMC Level 2
  • Cost of Noncompliance: Fines up to $10M for DFARS violations, loss of DoD contracts

Migration Steps to Microsoft 365 GCC High

Migrating to GCC High requires careful planning and execution. Follow these steps to ensure a smooth transition:

  1. Determine Eligibility
    • Before migrating, confirm your organization qualifies for GCC High
    • Microsoft requires proof that your company handles CUI, follows DFARS 7012, and supports DoD contracts
    • You must be a U.S. based entity
  2. Assess Your Current Environment
    • Perform a gap analysis of your existing M365 or on-premises infrastructure to determine what services, applications, and data need to be migrated
    • Identify any third-party integrations that may require adjustments for GCC High compatibility
  3. Acquire Licensing and Tenant Setup
    • Work with a Microsoft AOS-G partner to obtain GCC High licenses
    • Ensure you select the correct licensing tier based on your compliance needs
  4. Plan Your Migration Strategy
    • There are two primary migration approaches
      • Cutover Migration – Best for smaller organizations with limited data, this involves moving all users and data at once
      • Staged Migration – Ideal for larger environments, this method migrates users in phases to minimize disruption
      • Email Migration: Use tools like BitTitan or Quest to move Exchange data while maintaining security.
      • SharePoint & OneDrive: Migrate files while preserving permissions and metadata.
      • Other Services: Ensure compliance with GCC High requirements, as certain third-party apps may not be supported.
  5. Implement Security & Compliance Controls
    • Configure GCC High to align with NIST 800-171 and CMMC requirements
    • Conditional Access Policies – Restrict access based on device compliance, location, and identity
    • Multi-Factor Authentication (MFA) – Enforce MFA for all users, especially privileged accounts
    • Data Loss Prevention (DLP) – Configure policies to prevent unauthorized sharing of CUI
    • Logging & Monitoring – Enable Microsoft Defender for Office 365 and Azure Sentinel for security monitoring
  6. Conduct User Training & Change Management
    • After migration, validate security configurations and compliance requirements
    • Engage a C3PAO (Certified Third-Party Assessment Organization) if preparing for a CMMC Level 2 or 3 audit

Migrating to Microsoft 365 GCC High is a critical step for DoD contractors seeking to meet CMMC 2.0 and DFARS 7012 compliance. While the process requires planning and coordination, ensuring your cloud environment aligns with federal security standards protects your contracts and business continuity. It is key to know if your organization actually needs this before starting the process, as licenses are costly.

If your organization is preparing for GCC High migration, working with an experienced consultant can simplify the process and reduce risks.

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