A short update: The recent MSDN subscription migration kills my migrated account alias too. After contacting Microsoft support, I removed legacy alias from my account, create a new Microsoft Account using my legacy alias and restored my access to the new Visual Studio Subscription portal. In the same way, I removed legacy Microsoft Account in my Azure AD, linked two separated Microsoft Accounts(legacy and new alias) and resolved my issue accessing Visual Studio Team Services.
Such inconsistency always happens, and usually remove & add will be the universal solution in most cases.
After using legacy alias for almost 7 years, I decided to replace my Microsoft Account alias with a new Outlook.com email address due to increasing security concern of Netease Mail (my previous email service provider). Though I changed alternative recovery email to my domain email after several major security incidents, it looks weird to have an @163.com email alias linked to my Microsoft account.
Okay, I changed my alias the day before yesterday. It works. I didn’t delete the old one because I want to maintain some sort of backward compatibility. It works across my personal devices without any pain.
Annoying things came afterward days later.
Let’s talk about SSO/Federated Logon
Before talking about terrible things after switching to the new alias, let’s talk about Federated Logon. Technically speaking, Federated login is an authentication workflow based on trust relationships. Suppose Identity Provider A and Application B have successfully established two-way trust relationship by service provision. When a new user login attempt occurs, B redirects authentication challenges to Identity Provider A, with necessary metadata, like secure token ID, timestamp, nonce and finally something that validates the request, for example, digital signature, even token encryption. Since Application B has its own approach to understand Identity Provider A’s payload(so does B), the communication will be secured.
When Identity Provider A completes user authentication challenges(password, client certificate, fingerprint, etc.), it signs (encrypts maybe) authenticated user claims (user ID, user name and something else) and posts to B. The workflow image of WS-Federation below represents such workflow. OAuth and OpenID Connect have similar workflow with slight differences(multiple modes to retrieve user claims).
Microsoft Azure, Visual Studio Team Services and most Microsoft services use OpenID Connect. Believe it or not, you use Federated Logon and SSO every day.
Microsoft Account and Azure AD Account
They are two separated systems though they have something in common. Each Microsoft Account has a CID, a unique identifier in Microsoft Account system. All Microsoft Consumer services use CID to recognize your identity. For example, your Outlook.com email account is identified using your CID.
Azure AD Account handles it differently. Each Azure Active Directory have a tenant ID to identify AAD in AAD system. Each AAD contains objects: users, groups, computers, trust relationships….and more. Each AAD user has a unique alias in a specific AAD tenant. So the coexistence of 2ea6c0b4-cc49-42b8-9f1b-3f4aa653c719\imbushuo and b5093785-af31-4819-bf75-728d4474769c\imbushuo is possible.
Microsoft Accounts can be linked into Azure AD too: during the linking procedure, a new external user from Microsoft Account will be created in an AAD tenant, so you may have 2ea6c0b4-cc49-42b8-9f1b-3f4aa653c719\email@example.com. When Bill wants to access resources in his tenant’s AAD, he will type firstname.lastname@example.org in AAD Federation Service(Work and school account), a single sign on portal for Azure AD. Later, AAD FS will redirects the authentication challenges to Microsoft Account login portal. If Bill is authenticated in Microsoft Account login portal, he will be redirected back to AAD FS, with claims provided by Microsoft Account. Finally, AAD FS will tell the application that the user is Bill.
My blog uses such login mechanism too. See my management portal to get some idea about this if you don’t understand.
But…there’s no CID in Azure AD
But there’s something just works like CID: user alias. Another mapping! Microsoft Account will be mapped to Azure AD account, then the application will use the Azure AD account identity. After changing my alias in Microsoft Account, my Azure AD user alias remains the same. So I can login into my blog management portal with the same identity:
Do you remember that federation logon can carry multiple attributes at one time? So here’s the problem. My team’s source control service, Visual Studio Team Services, seems to use email address (which changes after rotating my primary Microsoft Account alias) to identity user. After logging in with my organization account, I found that my email address didn’t change after the rotation. To make the whole thing worse, I am the account creator, hence I cannot remove my Microsoft Account in VSTS to address the issue.
In short, the primary alias rotation didn’t change my user alias in Azure AD, but applications’ behavior vary based on how they deal with user claims.