12 Microsoft 365 Security Features and Best Practice Guidance – 9: Managing User Access with Role-Based Access Control (RBAC)

What is it?

Role-Based Access Control (RBAC) is a method of restricting user access based on their job roles within an organisation. Rather than assigning permissions directly to individual users, RBAC allows you to assign users to roles that come with predefined sets of permissions.

In Microsoft 365, RBAC is primarily implemented through Microsoft Entra ID (formerly Azure AD), Microsoft Exchange Online, and Microsoft 365 Defender. This model ensures users only have the minimum access needed to do their job, reducing the risk of accidental or malicious misuse of permissions.

For example:

• A helpdesk engineer might only have rights to reset passwords

• A compliance officer may only access audit logs and eDiscovery

• Security admins could manage Conditional Access policies and security alerts

RBAC is also foundational to Privileged Identity Management (PIM), where you can make roles eligible rather than permanently active, adding just-in-time access controls and approval workflows.

Why does it matter?

RBAC is vital for enforcing the principle of least privilege — a core tenet of Zero Trust security. Without role-based controls, users may be granted excessive access, which increases the blast radius of an account compromise.

Threat actors commonly exploit over-permissioned accounts. RBAC mitigates this risk by:

• Preventing privilege sprawl across teams and departments

• Enabling fine-grained, auditable access control

• Supporting separation of duties, especially for admin roles

• Reducing the impact of internal threats and misconfigurations

Using RBAC properly means your organisation is better protected against both targeted attacks and unintentional breaches caused by human error.

What does Microsoft recommend?

Microsoft strongly recommends adopting RBAC across your Microsoft 365 and Entra environments, particularly for administrative tasks.

Key recommendations:

• Use built-in roles rather than custom roles where possible to ensure compatibility and supportability

• Assign roles to security groups, not individuals, to streamline management and reduce risk

• Avoid using the Global Administrator role except where absolutely necessary

• Leverage Microsoft Entra Privileged Identity Management (PIM) to make sensitive roles “eligible” with just-in-time activation

• Regularly review role assignments for appropriateness using access reviews

In Microsoft 365 Defender and other portals, similar RBAC principles apply. Ensure roles like “Security Reader”, “Security Operator”, and “Compliance Admin” are only assigned where needed.

Best Practice Tips

• Review role assignments quarterly: Validate who has what level of access and why

• Use PIM where available: Activate admin roles only when needed, and require approval/MFA

• Limit Global Admins: Keep to a maximum of 2-4 for business continuity, but tightly control their usage

• Assign roles to groups: This makes role management easier and more consistent

• Monitor role changes: Use Microsoft 365 audit logs or Microsoft Sentinel to detect suspicious changes

• Document access policies: Maintain a clear matrix of who can do what and under which circumstances

• Use Conditional Access: Combine RBAC with Conditional Access for context-aware controls (e.g. allow admin access only from compliant devices)

How can HybrIT Help?

RBAC is a powerful but often underused tool for securing access within Microsoft 365. Many organisations either assign too many permissions or leave roles unmanaged over time, opening the door to unnecessary risk.

We can support you by:

• Auditing your current access control model and highlighting over-permissioned users

• Designing a role-based structure aligned with job functions and compliance needs

• Implementing Microsoft Entra PIM to control high-risk admin roles

• Configuring access reviews and alerts for role changes

• Integrating RBAC with Conditional Access to build layered, risk-aware policies

If you’re unsure where to start, we can help assess your environment and create a tailored roadmap to stronger access governance.

📞 Call us on 03330 156 702📧 Email hello@hybrit.co.uk