ASD's Blueprint for Secure Cloud

Authentication Policies

This section describes the design decisions associated with Authentication Policies for system(s) built using ASD's Blueprint for Secure Cloud.

Estimated reading time: 1 minute

Authentication policies control the authentication methods which can be used to access Exchange Mailboxes. Authentication polices can be leveraged to protect the organisation from brute force and spray attacks. To protect against this, Basic Authentication can be blocked. Basic authentication is where a username and a password are leveraged for client access requests.

Blocking Basic Authentication forces clients to use Modern Authentication. Blocking Basic Authentication can cause issues when clients within the environment do not support Modern Authentication. If this occurs, it is recommended to investigate whether the client can be upgraded to support Modern Authentication. If it can, then it is recommended that the client be upgraded. If it cannot then a separate authentication policy can be leveraged enabling Basic Authentication for that client only.

Security & Governance


  • None identified


  • None identified


  • None identified

Do you have a suggestion on how the above page could be improved? Get in touch! ASD's Blueprint for Secure Cloud is an open source project, and we would love to get your input. Submit an issue on our GitHub, or send us an email at

Acknowledgement of Country icon

Acknowledgement of Country
We acknowledge the Traditional Owners and Custodians of Country throughout Australia and their continuing connections to land, sea and communities. We pay our respects to them, their cultures and their Elders; past, present and emerging. We also recognise Australia's First Peoples' enduring contribution to Australia's national security.

Authorised by the Australian Government, Canberra