Microsoft 365 Tenant Security Audit: The Complete Guide
Identity, email, data, endpoints, compliance, and Copilot readiness. EPC Group's 47-Point Framework covers what Microsoft Secure Score misses.
A Microsoft 365 tenant security audit checks six domains: identity and access, email security, data protection, endpoint management, compliance posture, and Copilot readiness. EPC Group's 47-Point Framework covers all six. The audit runs 2 weeks and delivers a prioritized remediation roadmap.
Key Facts
- EPC Group's 47-Point M365 Security Audit covers 6 domains in 2 weeks.
- 34% of enterprises still have admin accounts without MFA — the most common gap found.
- The five most common findings: no admin MFA, overshared SharePoint sites, no sensitivity labels, legacy auth enabled, no DLP for Teams or Copilot.
- M365 E5 ($57/user/month) includes the complete toolset: Defender for Endpoint P2, Cloud Apps, Insider Risk, 6-year audit retention.
- EPC Group has completed 11,000+ enterprise M365 engagements since 1997.
Why Tenant Security Audits Matter Now
Quick Answer: A Microsoft 365 tenant security audit examines six key areas:
- Identity
- Data protection
- Endpoints
- Compliance
- Copilot readiness
This audit identifies misconfigurations, permission gaps, and compliance risks. On average, enterprises find 15-25 critical issues during their first audit.
With Copilot now inheriting user permissions, tenants that have not been audited risk exposing sensitive data through AI-powered search without realizing it.
Your Microsoft 365 tenant is crucial for your business operations. It manages email, stores documents, and facilitates meetings. It also oversees identity management.
With Microsoft Copilot, AI can now:
- Access all data within your tenant
- Query information efficiently
A security gap in your tenant is not just a theoretical risk. It is an active exposure that increases with:
- Onboarding new users
- Creating new sites
- Generating new sharing links
Many organizations see M365 security as a one-time task. They typically set up MFA during the initial deployment and create basic DLP policies. However, they often neglect to review these settings later. This oversight can result in:
- Increased vulnerability to security threats
- Inadequate protection of sensitive data
- Compliance issues with regulations
- Configuration drift
- Staff turnover
- New service deployments
- The introduction of Copilot
Over time, these factors can create security gaps.
In fact, the average enterprise tenant we audit has been operational for 5-8 years without a thorough security review.
EPC Group has audited over 700 Microsoft 365 tenants across healthcare, financial services, government, and Fortune 500 enterprises. Our 47-Point Security Framework was developed from patterns we see repeatedly — the same 15-20 critical gaps appear in nearly every tenant we assess. This guide walks you through what to audit, how to audit it, and when to bring in professionals.
The Copilot Factor: Before Copilot, a SharePoint site with overshared permissions was a latent risk — someone would have to navigate to the site and browse its contents to find sensitive data. With Copilot, that same overshared content is now surfaced proactively in response to natural language queries. Every permission gap in your tenant becomes an active data exposure path the moment you enable Copilot.
What to Audit: The Six Security Domains
A comprehensive M365 tenant audit looks at six related areas. Problems in one area can raise risks in others. For instance, weak identity controls can make data protection policies less effective. Also, poor endpoint management can undermine Conditional Access.
Identity & Access Management
- MFA enforcement across all user accounts and admin roles
- Conditional Access policies — location, device, risk-based
- Privileged Identity Management (PIM) for admin roles
- Guest and external user access review
- Service account inventory and credential rotation
- Break-glass emergency access account configuration
- Legacy authentication protocol elimination
- Sign-in risk and user risk policies (Entra ID P2)
Email Security
- Anti-phishing policies (impersonation protection, mailbox intelligence)
- Safe Attachments and Safe Links configuration
- DMARC, DKIM, and SPF record validation
- Outbound spam and bulk mail policies
- Mail flow rules audit (hidden forwarding rules)
- Quarantine policies and end-user access
- Attack simulation training enrollment
Data Protection
- Sensitivity label taxonomy and deployment status
- Auto-labeling policies for PII, PHI, financial data
- DLP policies across Exchange, SharePoint, Teams, OneDrive
- SharePoint external sharing settings (tenant and site level)
- SharePoint permission inheritance audit — broken inheritance sites
- OneDrive sharing defaults and link expiration
- Information barriers between regulated departments
- Azure Information Protection scanner results
- Copilot data exposure analysis (permission inheritance)
Endpoint Management
- Intune device compliance policies
- Conditional Access device trust requirements
- App protection policies (MAM for BYOD)
- Windows Update for Business ring configuration
- BitLocker encryption enforcement
- Microsoft Defender for Endpoint onboarding status
- Device inventory and stale device cleanup
Compliance & Governance
- Unified audit log enabled and retention configured
- Retention policies across Exchange, SharePoint, Teams
- eDiscovery case management and hold policies
- Communication compliance policies (if regulated)
- Insider risk management configuration
- Data lifecycle management automation
- Compliance Manager score and improvement actions
- Regulatory compliance mapping (HIPAA, SOC 2, FedRAMP)
Copilot & AI Readiness
- SharePoint oversharing analysis (sites accessible to "Everyone")
- Sensitivity label enforcement on Copilot-accessible content
- DLP policies for Copilot-generated outputs
- Teams meeting recording and transcription policies
- Information barriers preventing cross-department data leakage
- Guest access review (Copilot can surface guest-shared content)
- Stale and outdated content inventory
- Copilot usage monitoring and audit logging
EPC Group's 47-Point Security Framework
Our 47-Point Framework was developed by auditing over 700 tenants. It addresses 23 critical areas that Microsoft Secure Score overlooks. These areas include:
- SharePoint permission inheritance analysis
- Copilot data exposure modeling
- Compliance-specific configurations for HIPAA
- SOC 2
- FedRAMP
What You Get
- 47 specific security checkpoints across 6 domains
- Pass / Fail / Partial rating for each checkpoint
- Risk severity classification (Critical, High, Medium, Low)
- Specific remediation steps with estimated effort
- Copilot readiness score with data exposure analysis
- 40+ page report with executive summary
- Prioritized remediation roadmap (30/60/90 day)
- Compliance mapping to HIPAA, SOC 2, or FedRAMP
What Secure Score Misses
- SharePoint permission inheritance analysis
- Copilot data exposure risk modeling
- Sensitivity label enforcement effectiveness
- Cross-service data flow analysis
- Custom DLP policy quality assessment
- Teams meeting recording policy gaps
- Guest access cumulative exposure
- Stale content and outdated policy detection
DIY Audit vs. Professional Assessment
| Criteria | DIY (Secure Score + Admin Center) | Professional (EPC 47-Point) |
|---|---|---|
| Coverage | 40-50% of security gaps | 95%+ of security gaps |
| Identity & Access | MFA and basic CA policies | PIM, risk policies, service accounts, break-glass |
| SharePoint Permissions | Not covered by Secure Score | Full inheritance analysis across all sites |
| Copilot Readiness | Not covered | Data exposure modeling and remediation plan |
| Compliance Mapping | Generic compliance score | Industry-specific (HIPAA, SOC 2, FedRAMP) |
| Remediation Plan | Generic Microsoft recommendations | Prioritized 30/60/90 day roadmap with effort estimates |
| Cost | Free (staff time only) | $15,000 (2-3 week engagement) |
| Time to Complete | 1-2 weeks (part-time) | 2-3 weeks (dedicated team) |
Our Recommendation: Begin with a DIY review using Microsoft Secure Score. This will help you address clear gaps, such as:
- Enabling MFA
- Disabling legacy authentication
- Configuring basic DLP
Next, consider a professional assessment for a more thorough analysis. This should include:
- SharePoint permission inheritance
- Copilot data exposure
- Compliance-specific configurations
- Cross-service risk analysis
The $15,000 investment pays for itself by preventing a single data exposure incident.
Audit Frequency: How Often Should You Review?
Annual: Full 47-Point Assessment
Every organization should perform a complete security audit every year. This is essential due to factors like configuration drift, staff changes, new Microsoft features, and the changing threat landscape. Annual audits are also necessary for various compliance frameworks, including:
- ISO 27001
- GDPR
- HIPAA
- ISO 27001
- GDPR
- HIPAA
- HIPAA
- SOC 2
- FedRAMP
Quarterly: High-Risk Domain Review
Review the following areas quarterly to ensure security and effectiveness:
- Identity and access: Monitor new admin accounts and Conditional Access changes.
- SharePoint sharing settings: Check new sites and changed permissions.
- DLP policy effectiveness: Assess how well data loss prevention policies are working.
These areas change frequently and can have a significant impact if misconfigured.
Trigger-Based: Event-Driven Audits
Conduct targeted audits after specific events. These include:
- Deploying Copilot or other AI services
- Experiencing a security incident or near-miss
- Completing a merger or acquisition (tenant-to-tenant migration)
- Changes in regulatory requirements
- Significant staff turnover, especially among IT admins
- Enabling new M365 services such as Teams Phone, SharePoint Premium, or Viva
Continuous: Automated Monitoring
Enhance your audits with ongoing monitoring. Key components include:
- Microsoft Secure Score tracking
- Defender for Cloud Apps alerts
- Unified audit log analysis
- Copilot usage monitoring
Automated alerts help identify configuration changes and unusual access patterns between formal audits.
Post-Audit Remediation: The 30/60/90 Day Approach
An audit without remediation is just a report that gathers dust. EPC Group provides every audit with a clear remediation roadmap. This roadmap is organized into three phases:
- Phase 1: High-risk issues
- Phase 2: Medium-risk issues
- Phase 3: Low-risk issues
Each phase is based on risk severity and implementation effort.
Days 1-30: Critical Fixes
- Enforce MFA on all admin accounts (same day)
- Disable legacy authentication protocols
- Revoke "Everyone except external users" permissions on sensitive SharePoint sites
- Enable unified audit log if not already active
- Configure break-glass emergency access accounts
- Remove stale guest accounts and external sharing links
Days 31-60: High Priority
- Deploy Conditional Access policies (location, device, risk-based)
- Implement sensitivity label taxonomy and begin deployment
- Configure DLP policies for Exchange, SharePoint, Teams, and OneDrive
- Complete SharePoint permission inheritance remediation
- Enable Privileged Identity Management (PIM) for admin roles
- Deploy Intune compliance policies for managed devices
Days 61-90: Optimization
- Auto-labeling policies for PII, PHI, and financial data
- Information barriers between regulated departments
- Retention policies aligned with compliance requirements
- Copilot readiness validation and controlled pilot deployment
- Insider risk management policy configuration
- Continuous monitoring dashboards and alert configuration
Frequently Asked Questions
How do you audit your Microsoft 365 tenant for security?
A comprehensive M365 tenant security audit examines six domains: identity and access management (Entra ID, MFA, Conditional Access), email security (anti-phishing, DMARC, safe attachments), data protection (sensitivity labels, DLP policies, sharing settings), endpoint management (Intune compliance, device policies), compliance posture (retention policies, audit logs, eDiscovery), and Copilot readiness (permission inheritance, oversharing). EPC Group's 47-Point Framework covers all six domains in a structured assessment that takes 2-3 weeks to complete.
How often should you perform a Microsoft 365 security audit?
Organizations should perform a full M365 security audit at minimum annually, with quarterly reviews for high-risk areas. Trigger-based audits should occur after: deploying new services (Copilot, Teams Phone, SharePoint Premium), experiencing a security incident, changing compliance requirements, completing mergers or acquisitions, or significant staff turnover. Continuous monitoring through Microsoft Secure Score, Defender for Cloud Apps, and audit log analysis supplements periodic full audits.
What is Microsoft Secure Score and why does it matter?
Microsoft Secure Score is a numerical representation (0-100%) of your tenant's security posture based on Microsoft's recommendations. The average enterprise scores 40-55%. Scores above 70% indicate strong security hygiene. However, Secure Score has significant blind spots: it doesn't evaluate SharePoint permission inheritance, sensitivity label enforcement effectiveness, Copilot data exposure risk, or custom DLP policy quality. EPC Group's 47-Point Framework covers 23 areas that Secure Score misses entirely.
What are the most common M365 tenant security gaps?
The five most common security gaps we find during audits are: 1) MFA not enforced for all accounts — 34% of enterprises still have admin accounts without MFA, 2) SharePoint "Everyone except external users" permissions granting access to sensitive sites, 3) No sensitivity labels deployed or labels configured but not enforced, 4) Legacy authentication protocols still enabled (a top vector for credential stuffing attacks), 5) No DLP policies for Teams chat or Copilot-generated content. Most organizations have 15-25 critical findings in their first audit.
Should I do a DIY security audit or hire a consultant?
DIY audits using Microsoft Secure Score and the M365 admin center catch approximately 40-50% of security issues — primarily configuration-level gaps with clear Microsoft recommendations. Professional audits catch the remaining 50-60%: permission inheritance analysis, cross-service data flow risks, compliance gaps specific to your industry (HIPAA, SOC 2, FedRAMP), Copilot readiness assessment, and contextual risk prioritization. For regulated industries, a professional audit is not optional — auditors and regulators expect third-party validation.
What does EPC Group's 47-Point Security Framework include?
EPC Group's 47-Point Framework covers six security domains: Identity & Access (8 points: MFA enforcement, Conditional Access policies, PIM configuration, guest access controls, service account audit, break-glass accounts, legacy auth elimination, sign-in risk policies), Email Security (7 points), Data Protection (9 points), Endpoint Management (7 points), Compliance & Governance (8 points), and Copilot & AI Readiness (8 points). Each point receives a Pass/Fail/Partial rating with specific remediation steps, priority level, and estimated effort. The assessment takes 2-3 weeks and includes a 40+ page report with executive summary.
How much does a Microsoft 365 security audit cost?
Professional M365 security audit costs range from $8,000-$50,000 depending on scope: Basic audit (identity + email only): $8,000-$15,000. Comprehensive audit (all six domains): $15,000-$30,000. Enterprise audit with remediation roadmap (6+ domains, compliance mapping, Copilot readiness): $25,000-$50,000. EPC Group's 47-Point Security Review is $15,000 for the full six-domain assessment with detailed remediation roadmap. Remediation is typically scoped separately at $150-$250/hour depending on complexity.
Get Your Tenant Audited by the Experts
EPC Group offers Copilot & M365 Tenant Security Reviews for businesses across all sectors. We have secured over 700 tenants and have 29 years of Microsoft experience.
Our goal is to identify what Copilot can access that it should not. We focus on:
- Assessing security vulnerabilities
- Ensuring compliance with industry standards
- Protecting sensitive data
Begin with our 47-Point Security Review for $15,000. This includes a detailed report that is over 40 pages long.
The report provides:
- Pass/Fail ratings
- Risk classifications
- A prioritized 30/60/90 day remediation roadmap
Microsoft 365 Tenant Security Audit: Complete Guide 2026
A Microsoft 365 tenant security audit examines six key areas:
- Identity and access
- Email security
- Data protection
- Endpoint management
- Compliance posture
- Copilot readiness
EPC Group's 47-Point Framework addresses all six areas. The audit lasts 2 weeks and provides a prioritized remediation roadmap.
Key facts
- EPC Group's 47-Point M365 Security Audit covers 6 domains in 2 weeks.
- 34% of enterprises still have admin accounts without MFA — the most common gap found.
- The five most common findings: no admin MFA, overshared SharePoint sites, no sensitivity labels, legacy auth enabled, no DLP for Teams or Copilot.
- M365 E5 ($57/user/month) includes the complete toolset: Defender for Endpoint P2, Cloud Apps, Insider Risk, 6-year audit retention.
- EPC Group has completed 11,000+ enterprise M365 engagements since 1997.
What a tenant security audit covers
A comprehensive M365 audit examines six security domains. Each maps to specific controls in your tenant configuration.
- Identity and access — Entra ID, MFA enforcement, Conditional Access, PIM configuration, guest access, stale accounts.
- Email security — anti-phishing policies, DMARC/DKIM/SPF, Safe Attachments, Safe Links.
- Data protection — sensitivity labels, DLP policies, external sharing settings, encryption.
- Endpoint management — Intune compliance, device enrollment completeness, Defender for Endpoint deployment.
- Compliance and governance — retention policies, audit log settings, eDiscovery configuration, legal hold readiness.
- Copilot and AI readiness — permission inheritance audit, oversharing remediation, Copilot DLP, AI audit logging.
EPC Group's 47-Point Framework
Our structured framework maps 47 specific checkpoints across six domains. Here is the point breakdown.
- Identity and Access — 8 points: MFA enforcement, Conditional Access policies, PIM configuration, guest access controls, service account audit, break-glass accounts, legacy auth elimination, sign-in risk policies.
- Email Security — 7 points: DMARC/DKIM/SPF, anti-phishing, Safe Attachments, Safe Links, transport rules, external tag, attack simulation.
- Data Protection — 9 points: sensitivity labels, auto-labeling, DLP for email/SharePoint/Teams/Copilot, encryption, external sharing, Insider Risk, Information Barriers.
- Endpoint Management — 7 points: Intune enrollment, device compliance, ASR rules, Autopilot, tamper protection, USB controls, Defender onboarding.
- Compliance and Governance — 8 points: unified audit logging, retention policies, eDiscovery, legal hold, Compliance Manager score, Customer Lockbox, data lifecycle, records management.
- Copilot and AI Readiness — 8 points: permission inheritance audit, overshared site remediation, Copilot DLP, Restricted SharePoint Search, AI audit logging, acceptable use policy, sensitivity label enforcement, Copilot usage reporting.
The five most common audit findings
- MFA not enforced for admin accounts — found in 34% of enterprise tenants audited.
- SharePoint "Everyone except external users" permissions — grants broad access to sensitive sites without the team knowing.
- No sensitivity labels deployed — or labels configured but not enforced with policies.
- Legacy authentication still enabled — a top vector for credential stuffing attacks.
- No DLP policies for Teams chat or Copilot content — leaves regulated data unprotected in modern collaboration channels.
M365 licensing for security audits
- E3 ($36/user/month) — covers identity, basic DLP, Conditional Access, 90-day audit logs.
- E5 ($57/user/month) — adds Defender for Endpoint P2, Cloud App Security, Insider Risk Management, 6-year audit retention, Customer Lockbox.
- E5 Security add-on ($12/user/month) — adds E5 security features to an E3 base.
- E5 Compliance add-on ($12/user/month) — adds advanced compliance to an E3 base.
Frequently asked questions
What does a Microsoft 365 tenant security audit cover?
EPC Group focuses on six key domains:
- Identity and access management
- Email security
- Data protection
- Endpoint management
- Compliance posture
- Copilot readiness
Our 47-Point Framework evaluates specific configurations in each domain. It then creates a prioritized roadmap for remediation.
How long does an M365 tenant audit take?
EPC Group conducts a 47-point audit within 2 weeks. At the end of week two, you will receive:
- Findings from the audit
- A prioritized remediation roadmap
The remediation process will depend on the number and severity of gaps identified.
What are the most common M365 security gaps?
Here are the top five security issues:
- Admin accounts without MFA
- Overly broad SharePoint permissions
- Sensitivity labels not deployed
- Legacy authentication protocols still active
- No DLP coverage for Teams chat or Copilot-generated content
Do I need M365 E5 to be secure?
E3 includes the basic controls. E5 provides advanced features such as:
- Defender for Endpoint Plan 2
- Insider Risk Management
- Cloud App Security
- 6-year audit retention
For regulated industries like HIPAA, FedRAMP, and CMMC, E5 or specific add-ons are usually required.
What is GCC High and when do I need it?
GCC High is a Microsoft 365 environment designed for federal contractors managing Controlled Unclassified Information (CUI). It has specific compliance requirements:
- CMMC Level 2 requires 110 NIST 800-171 controls.
- CMMC Level 3 requires 134 controls.
Commercial M365 does not meet these requirements.
How does the audit address Copilot readiness?
We evaluate 8 key areas related to Copilot:
- Permission inheritance
- Overshared sites
- DLP coverage
- Restricted SharePoint Search configuration
- AI audit logging
- Sensitivity label enforcement on Copilot-accessible content
- Acceptable use policy
- Usage reporting setup
Schedule a 47-point tenant audit
EPC Group's 2-week M365 Tenant Security Audit delivers a complete security picture and a remediation roadmap. Call (888) 381-9725 or request a discovery call.