Updated 14JAN2022 - The github link below has been updated to simplify the setup of the application registrations in Azure and allows for full testing in Jamf Connect Configuration before deploying to a test machine.
https://www.jamf.com/blog/how-to-azure-conditional-access-and-jamf-connect/ - Updated instructions posted to Jamf Blog.
UPDATED: 10 December 2021 - Includes information on how to create a custom scope for Microsoft Azure Conditional Access policies.
Overview: This covers the following topics:
- Administrators finding "failed" login attempts in Azure sign-in logs when using Jamf Connect
- How the ROPG workflow and Jamf Connect communicate
- How to make an App Registration in Microsoft Azure Active Directory that allows for Conditional Access policies
- How to make Conditional Access policies NOT apply to the ROPG workflow
Problem:
Administrators may observe failed login attempts in the log for the enterprise application created in Microsoft Azure Active Directory when using Jamf Connect and a Conditional Access policy that requires multi-factor authentication for the target of "All cloud apps." While this is expected behavior of the Resource Owner Password Grant (ROPG) workflow, it may trigger a user appearing in the Risky Sign-Ins in Azure Active Directory security reports.
What is happening:
The target of "All cloud apps" applies policies far beyond the logins to specific cloud services and applies policies to non-interactive workflows like those with ROPG. Specifically, the "All cloud apps" appears to apply to any application requesting a login with the scope of any of the following:
openid profile email
The Open ID Connect 2.0 specification uses these default scopes to obtain an access or identity token for a client application. Consequently, in its default configuration, Jamf Connect login uses the "openid profile email" scope in its authentication requests, and the only way to apply a CA policy in this default behavior is to apply the policy to "All cloud apps" with NO exceptions applied or the CA policy will break.
Administrators have multiple options for solutions to enforce MFA on the Jamf Connect login screen:
- Simplest, but most impact on user logins: Set hard requirements for MFA via the older method of Azure Multi-Factor Authentication which applies an MFA requirement to ALL logins to ANY service for a specific user. Ignore failed logins in the sign-in logs for ROPG checks of the password. (Additional information on how to determine if a failed login is due to Jamf Connect menu bar agent doing an ROPG request is below.)
- Simple, but may affect other services: Apply a Conditional Access policy applied to "All cloud apps" requiring Multi-factor Authentication for login. Do NOT use an exception to the policy as that appears to break functionality of the CA rule as of testing done 10DEC2021. Ignore failed logins in the sign-in logs for ROPG checks of the password.
- Complex, but exacting: Follow the instructions from https://github.com/sean-rabbitt/jamf-connect-azure-conditional-access/ to create a custom scope for Jamf Connect applications. Verify that no policies are created that apply to "All cloud apps" as to not affect the ROPG workflow. CA policy will be applied as expected to the Jamf Connect login application and ROPG check will appear as a successful login in sign-in logs.
Azure Multi-factor Authentication vs. Conditional Access
Administrators can enable multi-factor authentication requirements for a user account in two ways:
- Multi-factor Authentication which is reachable via the “All services” list in the Azure portal
- Conditional Access which is reachable via Azure Active Directory under Security
Multi-factor Authentication is a system wide, all login attempts, master switch system for enforcing MFA at authentication. While IP address ranges can be exempted, the rules apply to all authentications.
Conditional Access allows for fine grain details to apply for when MFA is required including exempting MFA for web applications.
Resource Owner Password Grant workflow
Jamf Connect uses a Resource Owner Password Grant (ROPG) workflow to synchronize the user’s password in the identity provider with the password on the user’s client machine. The user name and the password are sent to the identity provider in a “non-interactive” login to receive a response. This means that the user is not prompted for any sort of user name or password when logging in; Jamf Connect is using the information securely stored in the user’s keychain for this event.
For Azure, the responses are one of the following:
- Success, no MFA requirements: An access, refresh, and ID token encoded in HS256
- Success, MFA required through a policy: An error response like
AADSTS50076: Due to a configuration change made by your administrator, or because you moved to a new location, you must use multi-factor authentication to access [application UUID]
- Failure, bad password or user name: An error response like
AADSTS50126: Error validating credentials due to invalid username or password.
As long as the user password is correct, the ROPG flow has succeeded - the password has been validated to be correct. Whereas Jamf Connect has no need for the access, refresh, and ID token to keep the local password in sync with the identity provider, an appropriate error response is interpreted as a successful password check.
Diagnosing MFA vs. failed password in Azure logs
Navigate to Azure Active Directory → Enterprise Applications and select the name of your Jamf Connect application in Azure. Navigate to Activity → Sign-ins to open user usage logs.
Shown above are two logins which appear to be failures. Under the “Authentication required” column, the first login says “Multi-factor authentication”. Clicking on the row will pull up additional details about the login attempt.
Under Authentication Details, the “Result detail” will let an administrator determine if the login was successful or a failure. In this example, the login was a success - the Result detail shows that the “User did not pass the MFA challenge (non interactive).” This login can be interpreted in that the user was required to use MFA by either a Conditional Access policy or through Azure Multi-factor authentication.
In the second example, a user with MFA required failed to enter their correct password:
The Authentication required column shows “Single-factor authentication” and the Authentication Details show “Invalid username or password or Invalid on-premise username or password.” While the user is required to use Multi-factor authentication, the user failed the first, single factor and thus was never prompted for MFA.
Creating a custom scope for Jamf Connect
To eliminate the inaccurate "failed responses" for ROPG, admins must remove any "All cloud apps" scoped requirements for multi-factor authentication and create a custom scope for Jamf Connect login.
Follow the guide in Azure_Conditional_Access_and_Jamf_Connect.pdf (source: GitHub) for step by step instructions.
Conditional Access Policy Considerations
Several Conditional Access Grant policies can create unacceptable behavior to access a client device:
- Require device to be marked as compliant
- Require Hybrid Azure AD joined device
In the above cases, a user would be unable to log into a client machine to fix the issue of being out of compliance by running a Jamf Pro policy to get the device back into compliance.
- Require approved client app
- Require app protection policy
In the above cases, the Jamf Connect software is not of the Microsoft apps accessing a specific service (for example, Microsoft Outlook accessing O365 mail), and all access would be blocked.
Administrators are recommended to carefully read conditional access polices and conditions applied to avoid locking users out of client devices inadvertently.
