MVC Identity cookie is authenticated across subdomains

Question

So in my googling, I have come across alot of people struggling to enable cross domain support fir Identity. However somehow I have this as standard. The application setup is that we have a domain where each customer has a subdomain. We upload a new web app for each customer.

The problem seems to be that if I log in at xxx.foo.com, I am also logged in at yyy.foo.com.

I can't seem to find anything regarding turning this feature off. The Identity setup hasn't been changed much from the standard template. Below is the Startup.Auth.cs code:

public void ConfigureAuth(IAppBuilder app)
{
    // Configure the db context, user manager and signin manager to use a single instance per request
    app.CreatePerOwinContext(DataContext.Create);
    app.CreatePerOwinContext<UserManager>(UserManager.Create);
    app.CreatePerOwinContext<ApplicationSignInManager>(ApplicationSignInManager.Create);
    app.CreatePerOwinContext<ApplicationRoleManager>(ApplicationRoleManager.Create);

    // Enable the application to use a cookie to store information for the signed in user
    // and to use a cookie to temporarily store information about a user logging in with a third party login provider
    // Configure the sign in cookie
    app.UseCookieAuthentication(new CookieAuthenticationOptions
    {
        AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
        //LoginPath = new PathString("/Account/BadRights"),
        LoginPath = new PathString("/Account/Login"),
        Provider = new CookieAuthenticationProvider
        {
            // Enables the application to validate the security stamp when the user logs in.
            // This is a security feature which is used when you change a password or add an external login to your account.  
            OnValidateIdentity = SecurityStampValidator.OnValidateIdentity<UserManager, User>(
                validateInterval: TimeSpan.FromMinutes(10),
                regenerateIdentity: (manager, user) => user.GenerateUserIdentityAsync(manager))
        },
    });            
    app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);

    // Enables the application to temporarily store user information when they are verifying the second factor in the two-factor authentication process.
    app.UseTwoFactorSignInCookie(DefaultAuthenticationTypes.TwoFactorCookie, TimeSpan.FromMinutes(5));

    // Enables the application to remember the second login verification factor such as phone or email.
    // Once you check this option, your second step of verification during the login process will be remembered on the device where you logged in from.
    // This is similar to the RememberMe option when you log in.
    app.UseTwoFactorRememberBrowserCookie(DefaultAuthenticationTypes.TwoFactorRememberBrowserCookie);
}

Any help or hints to what I should be looking for is greatly appreciated.

Answer 1

You must build an identity server to login with SSO.

You can find details here