Copilot Security Review

Microsoft Copilot Security Review: Enterprise Assessment Methodology (2026)

A Microsoft Copilot security review is the structured assessment that determines whether your Microsoft 365 tenant is ready for Microsoft 365 Copilot, Microsoft Copilot Studio agents, Microsoft Power BI Copilot, and GitHub Copilot Enterprise — without exposing PHI, MNPI, CUI, IP, or other sensitive data.

EPC Group has delivered Microsoft Copilot security reviews for Fortune 500 healthcare, financial services, government, manufacturing, and pharma since the Microsoft 365 Copilot early adopter program (2023).

TL;DR — Microsoft Copilot Security Review 7-Domain Framework

Domain	Microsoft Component
1. Identity hardening	Microsoft Entra MFA + Conditional Access + PIM
2. Sensitivity labeling	Microsoft Purview labels (5-tier with industry sub-tiers)
3. SharePoint oversharing	Microsoft Restricted SharePoint Search + permission cleanup
4. DLP coverage	Microsoft Purview DLP per data class
5. AI risk monitoring	Microsoft Purview AI Hub + Microsoft Sentinel custom rules
6. Audit retention	Microsoft Purview Audit (Premium)
7. Compliance attestation	Microsoft Compliance Manager + industry frameworks

Domain 1: Identity Hardening

• 100% MFA coverage
• Hardware token / FIDO2 / PIV/CAC for privileged
• Conditional Access policies (geo-fence, device compliance, risk-based)
• Microsoft Entra ID Protection
• Microsoft Entra Privileged Identity Management
• Service principal review (third-party app access to Microsoft 365)

Domain 2: Sensitivity Labeling

5-tier with industry-specific Restricted sub-labels:

• Public, General, Confidential, Highly Confidential
• Restricted-PHI (healthcare)
• Restricted-MNPI (financial services)
• Restricted-CUI (government)
• Restricted-Clinical (pharma)
• Restricted-Trading (financial services)

Restricted-tier blocks Microsoft Copilot grounding.

EPC Group standard: 80%+ coverage on regulated content within 90 days.

Domain 3: SharePoint Oversharing

The Microsoft 365 Copilot oversharing risk exists because Copilot grounds on whatever the requesting user can already access — including content that was over-shared at the SharePoint or OneDrive level.

Microsoft Restricted SharePoint Search (Day 1 Mitigation)

Limits Microsoft Copilot SharePoint grounding to a curated allowlist of sites for the first 90-180 days while permissions are remediated.

Permission Cleanup

• Sites with anonymous link sharing
• Files shared "Everyone except external"
• Sites without proper sensitivity labels
• Orphaned permissions
• Stale guest accounts

EPC Group standard: 90-180 day permission cleanup before Restricted Search lift.

Domain 4: DLP Coverage

Microsoft Purview DLP across:

• Microsoft Exchange (email)
• Microsoft SharePoint (sites)
• Microsoft OneDrive (personal storage)
• Microsoft Teams (chat + channels)
• Microsoft Endpoint DLP (devices)

Industry-specific data classes:

• Healthcare (PHI patterns)
• Financial services (PCI, financial account numbers)
• Government (CUI markings)
• Pharma (clinical trial identifiers)

Domain 5: AI Risk Monitoring

Microsoft Purview AI Hub

• Microsoft Copilot prompt + response monitoring
• Sensitive data exposure detection
• Risk scoring per user
• Compliance reporting

Microsoft Sentinel AI Analytics

• Custom analytics rules for Copilot risk events
• Microsoft Copilot Studio agent monitoring
• Cross-correlation with Microsoft Purview Insider Risk

Domain 6: Audit Retention

• Microsoft Purview Audit (Premium)
• 7-year retention for HIPAA / FINRA tenants
• 10-year retention for SEC Rule 17a-4 broker-dealers
• All Microsoft Copilot prompts + responses logged

Domain 7: Compliance Attestation

• Microsoft Compliance Manager industry framework templates
• Customer-Responsibility Matrix
• POA&M tracking for control gaps
• Annual third-party assessment readiness

Microsoft Copilot Security Review Engagement

EPC Group fixed-fee Microsoft Copilot Security Review:

• Mid-market: $50K-$120K (4 weeks)
• Enterprise: $120K-$300K (6-8 weeks)
• Fortune 500: $300K-$600K (8-12 weeks)

Deliverables

• 7-domain security gap analysis report
• Microsoft Restricted SharePoint Search Day 1 deployment
• Microsoft Purview AI Hub configuration
• Microsoft Sentinel custom analytics rule library
• Microsoft Compliance Manager attestation evidence package
• 90-day remediation roadmap with owners + dates

Frequently Asked Questions

Should we deploy Microsoft Copilot without a security review?

Microsoft itself recommends Microsoft Copilot security review prior to enterprise rollout. Without it, oversharing risk + sensitivity labeling gaps create regulator-flaggable exposure.

How long does the review take?

Mid-market: 4 weeks. Enterprise: 6-8 weeks. Fortune 500: 8-12 weeks.

What about Microsoft Copilot Studio agents?

Microsoft Copilot Studio custom agents require additional review for grounding source DLP, agent permission scope, and Microsoft Sentinel telemetry coverage.

Who delivers EPC Group Microsoft Copilot security reviews?

Errin O'Connor (Founder & Chief AI Architect, 4-time Microsoft Press & Sams author) leads. Senior security architects with Microsoft Defender, Microsoft Purview, Microsoft Sentinel, and industry-specific compliance credentials (CHPS, CISSP, CISA, FedRAMP 3PAO, CIPP, CSV).

Next Steps

Schedule a 30-minute Microsoft Copilot security review discovery call at /schedule or call (888) 381-9725. Senior architects (not sales) take discovery calls.

Related reading: Microsoft 365 Copilot Security Best Practices, Microsoft Copilot Governance Framework for Regulated Industries, Copilot SharePoint Permissions Oversharing Fix, Is Microsoft Copilot Safe Enterprise Assessment, and Microsoft 365 Security Best Practices.