Office 365 - Exchange Online Basic Authentication

Most logins to Microsoft Office 365 Exchange require direct authentication to NetID Login. However, some clients/protocols use basic authentication. With basic authentication (also called proxy authentication), the email client transmits the username and password to Office 365, and Office 365 forwards the provided credentials to NetID Login. This article answers general questions about Basic Authentication.

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How does basic authentication work in Office 365?

With basic authentication, your email/calendar client will transmit your username and password to Office 365 (Exchange Online). Office 365 will forward your credentials to the NetID Login Service. The NetID Login Service will verify the credentials and return a token to Office 365. If authentication was successful and the user is authorized, the email/calendar client will be connected to Office 365.

What is modern authentication?

If your email/calendar client uses modern authentication, your credentials are not sent to Office 365 (Exchange Online). Instead, you'll be redirected to the familiar NetID Login screen. If your account is protected by Duo MFA, you will be required to confirm your login. Your client may maintain a connection to Office 365 with an OAuth token, so you may not be required to use NetID Login each time you use the client.

Which clients require basic authentication?

Office 365 does not support modern authentication with IMAP, POP, and SMTP protocols. If you're using an IMAP client like Thunderbird or if you POP your email to Gmail, login is completed via basic authentication. Office 365 allows for either basic or modern authentication with Exchange Web Services (EWS) and Exchange ActiveSync (EAS). Depending on support within your email/calendar client, you may be required to use basic authentication to use EWS or EAS.

Which clients are capable of modern authentication in Office 365?

The following clients are capable of authenticating to Office 365 Exchange Online with modern authentication:

How is basic authentication less secure than modern authentication?

Basic authentication in Office 365 is less secure for multiple reasons:

How long will Microsoft support basic authentication in Office 365?

Microsoft has already discontinued support for basic authentication with Outlook REST API. Microsoft has announced an end of support for basic authentication with EWS, EAS, POP, IMAP, Remote PowerShell (RPS) on 10/13/2020. Support for basic authentication with Office 365 SMTP is expected to continue beyond 2020.

Important: Microsoft has decided to delay/suspend the removal of Basic Authentication from Exchange until further notice. Learn more.

To manage this feature, please review the Office 365 - Manage Password Security article.

How can I disable basic authentication to my account?

If you are using Basic authentication to connect to your email account, you may be suspect to any of the following: unauthorized access, use of your NetID credentials for credential stuffing, brute force, and password spray cyberattacks.

To protect your account and NetID credential, it is highly recommended that you make sure Password Security is enabled on your account - to manage this feature, please review the Office 365 - Manage Password Security article.

How can I reconfigure Exchange to use modern authentication on my devices?

To begin using modern authentication through exchange, open a desktop or mobile email client, remove your UW Madison email address, and then re-add your UW Madison email address. When authenticating the account, you should receive a pop up or be redirected to UW Madison's secure login portal, which is the only time you should enter your password.

Information regarding how to configure specific mail clients can be found in:

How do I configure a client with a legacy protocol for modern authentication?

Microsoft supports authentication to O365 with "legacy" protocols: IMAP, POP, and SMTP. Any client that supports OAuth 2.0 should be able to authenticate to Office 365. Support for OAuth 2.0 with O365 is dependent upon the client developer. The UW-Madison Office 365 team has no control over client support. Configuration instructions will be unique for each client, but you can refer to the Thunderbird IMAP/SMTP modern authentication configuration instructions found here: Office 365 (Thunderbird) - Configure Modern Authentication

I'd like to learn more about Office 365 authentication.

If you'd like to learn more about basic and modern authentication in Office 365, please review the following documents:

See Also: