Entra application accounts

Application only authentication allows Cayosoft Guardian to connect to Microsoft 365 services without using the credentials of a real user account (such as a Global Administrator). Instead, Guardian uses a single-tenant application and its associated service principal (enterprise app) in Microsoft Entra ID.

This approach aligns with Microsoft’s best practices by eliminating dependency on highly privileged user accounts, reducing exposure of credentials, and supporting scenarios where interactive logins are restricted (for example, regulated or service-only environments).

Application only authentication provides several advantages for administrators. It removes the need to store or rotate privileged user credentials, which reduces both operational overhead and security risks. By avoiding Global Administrator sign-ins, it minimizes the attack surface while ensuring compliance with Microsoft’s security baseline recommendations. This method also delivers reliability in automated, service-only, or highly regulated environments where interactive sign-ins are not allowed.

How it works in Guardian

• Cayosoft Guardian creates a single-tenant application in Entra ID. Learn more: Configuration: Add a Tenant
• A corresponding enterprise application (service principal) is registered in each managed tenant.
• A certificate credential is generated and securely stored for authentication.
• The certificate is automatically rotated every 30 days (configurable) and can also be manually renewed in the UI.

Role assignments and permissions

For more details on the changes made in the environment, see Connection accounts in Guardian

References

• Register a Microsoft Entra app and create a service principal
• Add and manage application credentials in Microsoft Entra ID
• Apps and service principals in Microsoft Entra ID
• Best practices for Microsoft Entra roles