A Microsoft 365 security assessment is a structured review of tenant settings, identity controls, collaboration services, and endpoint management posture. It identifies misconfigurations against established baselines so teams can see where exposure exists and what needs to change. In practice, it turns a complex cloud environment into a prioritised remediation list.
Expanded Definition
A Microsoft 365 security assessment is a structured review of tenant configuration, identity posture, collaboration controls, and endpoint governance across the Microsoft 365 stack. It is broader than a permission audit because it examines how policy, authentication, sharing, device compliance, and admin roles interact to create exposure.
For NHI and agentic AI environments, the assessment also needs to account for service accounts, automation identities, OAuth applications, and API-driven workflows that inherit tenant trust. Definitions vary across vendors on how deeply this should extend into workload identity, but the operational goal is consistent: identify where standing access, weak rotation, or excessive consent breaks the intended control model. A practical benchmark is the NIST Cybersecurity Framework 2.0, which treats identity, configuration, and resilience as interconnected risk domains.
The most common misapplication is treating a Microsoft 365 security assessment as a one-time admin checklist, which occurs when tenant review is separated from ongoing identity governance and remediation ownership.
Examples and Use Cases
Implementing a rigorous assessment often introduces remediation backlog and service disruption risk, requiring organisations to weigh visibility gains against the operational cost of change management.
- Reviewing Entra ID conditional access, legacy authentication, and admin role assignments after an incident to identify how access was obtained.
- Checking Exchange, SharePoint, and Teams sharing settings to reduce external exposure and ungoverned collaboration paths.
- Auditing OAuth applications and consent grants to find overbroad permissions, especially where third-party integrations or automation agents are involved, as seen in the CoPhish OAuth Token Theft via Copilot Studio research.
- Validating Intune compliance baselines and device controls to ensure endpoint posture matches identity trust assumptions, similar to lessons from the Stryker Microsoft Intune Wiper Attack.
- Comparing tenant findings against the NIST Cybersecurity Framework 2.0 and Microsoft hardening guidance to prioritise controls that reduce blast radius.
NHIMG research shows that 85% of organisations lack full visibility into third-party vendors connected via OAuth apps, which makes assessment work especially valuable when app consent sprawl is already present. A Microsoft 365 security assessment is often the first point where those hidden connections become visible, particularly after reviewing cases like the Microsoft OAuth Breach.
Why It Matters in NHI Security
Microsoft 365 is not just a productivity platform. It is a control plane for identities, secrets, collaboration content, and administrative actions. When assessments miss non-human identities, the result is often overconfidence in tenant security while service principals, scripts, and app registrations keep broad access that humans no longer review. NHIMG research from The Ultimate Guide to NHIs shows that 97% of NHIs carry excessive privileges and 96% of organisations store secrets outside secure managers, which makes Microsoft 365 review work directly relevant to containment and resilience.
This is also where broader identity failures become visible. The Microsoft Midnight Blizzard breach and the Microsoft Entra ID Flaw both reinforce that tenant-level weaknesses can cascade into cloud-wide compromise when identity controls are weak or poorly governed.
Organisations typically encounter the business impact only after a token theft, lateral movement event, or tenant compromise, at which point Microsoft 365 security assessment findings become operationally unavoidable to address.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 and OWASP Agentic AI Top 10 address the attack and risk surface, while NIST CSF 2.0, NIST Zero Trust (SP 800-207) and NIST SP 800-63 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-02 | Covers secret storage, rotation, and exposure risks in non-human identity environments. |
| NIST CSF 2.0 | PR.AC-1 | Identity and access control review is central to Microsoft 365 assessment work. |
| NIST Zero Trust (SP 800-207) | SCG | Zero Trust relies on continuous verification of user, device, and workload trust. |
| NIST SP 800-63 | AAL2 | Assurance levels help judge whether authentication strength matches tenant risk. |
| OWASP Agentic AI Top 10 | A03 | Agent and tool access risks map to consent, permission, and execution governance. |
Find and remove exposed secrets, then enforce rotation and least-privilege access for all tenant-linked NHIs.
Related resources from NHI Mgmt Group
- How should security teams govern consented Microsoft 365 applications?
- How should security teams handle overshared Microsoft 365 files at scale?
- How should security teams prepare Microsoft 365 permissions for Copilot adoption?
- How should security teams use DSPM alongside Microsoft 365 access reviews?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on August 27, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
