Firebase Authentication email-already-in-use error? - firebase-authentication

I read this section of the Firebase documentation: https://firebase.google.com/docs/reference/js/firebase.auth.Auth.html#getredirectresult
and I can't see the difference between these two errors:
auth/account-exists-with-different-credential
and
auth/email-already-in-use
The former says
Thrown if there already exists an account with the email address asserted by the credential
And the latter says
Thrown if the email corresponding to the credential already exists among your users
This and the rest of the paragraphs say the same thing to me, with different words. Any comments on this would be appreciated. Thank you

From what I see in my tests, I would now say that:
auth/account-exists-with-different-credential: happens when the user signs in with a provider credential which is not yet linked to one of our accounts, but which references an email address which is used by one of our accounts
auth/email-already-in-use: happens when trying to link a provider credential which is not yet linked to one of our accounts, but which references an email address which is used by one of our accounts
So basically they are the same thing so far, but happen after different events. In this case, maybe auth/account-exists-with-different-credential should have been used instead, I'll email the Firebase support about this.
But auth/email-already-in-use also happens when trying to link an email credential while the email is already used by one of our accounts. In which case it does make sense.

Related

Email enumeration through login and forgot password functionality

The login and forgotten password functions can be used to enumerate valid email addresses on the application, as they return different messages depending on whether or not the emails are registered. Is there a way to avoid this?
This question was asked before: Google Identity Toolkit v3 Email enumeration through reset password functionality but remains unanswered so posting here with the google-oauth tag to see whether it reaches the right people.

NextAuth - OAuthAccountNotLinked - Imported data from another website - Autolinking

I have OneLogin setup in my application and is working fine. Am using MongoDB database for storing the sessions, accounts and users.
And now, I imported user data from my old WordPress website(which doesn't uses OneLogin, but the native WordPress login).
So basically I imported the user data from WordPress and populated the users collection using the email_id, name, etc. When I login with the OneLogin into my application, it throws the error saying OAuthAccountNotLinked. When researched I can see that you are not recommending the auto-linking of user accounts for safety reasons. But in my case, it's a OneLogin provider that my client's organization that has now started using. And new OneLogin user registrations are manually approved by the admin. So security wise it won't be a problem. We are only using OneLogin as auth provider!
How can I setup auto-linking in this scenario? Because I have 10,000s of Users in my MongoDB collection(imported from old WordPress website). And each User is being requested to manually register at OneLogin using the same email id they were using before in the old WordPress website and is manually approved within the OneLogin.
Thanks
Quote right from the original site
Automatic account linking on sign in is not secure between arbitrary providers - with the exception of allowing users to sign in via an email addresses as a fallback (as they must verify their email address as part of the flow).
When an email address is associated with an OAuth account it does not necessarily mean that it has been verified as belonging to account holder — how email address verification is handled is not part of the OAuth specification and varies between providers (e.g. some do not verify first, some do verify first, others return metadata indicating the verification status).
With automatic account linking on sign in, this can be exploited by bad actors to hijack accounts by creating an OAuth account associated with the email address of another user.
For this reason it is not secure to automatically link accounts between arbitrary providers on sign in, which is why this feature is generally not provided by authentication service and is not provided by NextAuth.js.
Automatic account linking is seen on some sites, sometimes insecurely. It can be technically possible to do automatic account linking securely if you trust all the providers involved to ensure they have securely verified the email address associated with the account, but requires placing trust (and transferring the risk) to those providers to handle the process securely.
Examples of scenarios where this is secure include with an OAuth provider you control (e.g. that only authorizes users internal to your organization) or with a provider you explicitly trust to have verified the users email address.
Automatic account linking is not a planned feature of NextAuth.js, however there is scope to improve the user experience of account linking and of handling this flow, in a secure way. Typically this involves providing a fallback option to sign in via email, which is already possible (and recommended), but the current implementation of this flow could be improved on.
Providing support for secure account linking and unlinking of additional providers - which can only be done if a user is already signed in already - was originally a feature in v1.x but has not been present since v2.0, is planned to return in a future release.
You probably need to write your own implementation to handle such a situation. And call that implementation on each provider call back. Like a check, the email already exists in DB, through an extra level of verification like OTP etc. Finally, when everything passes, let the user in and store some extra info in the DB for future reference.
Since I wasn't able to find a straight forward solution, I come up with a workaround. It's not a perfect solution, but does the job. Maybe someone else will post a better solution here.
So what I did is, I have all the old user data imported to the users collection in my MongoDB database. And NextAuth uses this users, accounts and session collections to store the User and related data. Btw am storing the session data in database.
In my case, we have sent unique OneLogin registration URLs(created from the OneLogin Admin Dashboard) to our existing users for them to create a new account in OneLogin. Then when the User registers an account at OneLogin, the admin approves/rejects the User. If they are approved, they will be eligible to login to our app using their OneLogin credentials.
What I noticed is that, when a User tries to login, NextAuth checks the email field in users collection to find a matching record. Since we imported the Users from WordPress database, we only have records in users collection and nothing on the accounts collection. In accounts collection, NextAuth is storing the access_token, user_id (mapping to users collection), provider details, etc.
So during login, the NextAuth does the internal checks and finds the existing email in the users collection, but it fails to identify the user as there's no info about the provider(OneLogin) details.
Record from accounts collection:
So what I did is, updated all records in users collection by appending a _TEMP to the email field's values. For example, if there's a record with the value abc#abc.com, it will become abc#abc.com_TEMP
Then what I did is, I wrote an API route(/api/check_old_account) in my NextJS application, where it does the following:
gets the currently logged in User's email id (from NextAuth session)
searches the users collection for the same email id with a "_TEMP" at the end
if there exists a _TEMP version of the currently logged in User, then return a response saying an old account exists
Then in the HOME page, I wrote the code to call the above mentioned api (/api/check_old_account) if the User is logged in. This call is made only once in the HOME page, when everything is loaded. Here the login using OneLogin works without errors because we renamed the existing email id in users collection by appending _TEMP. So when User logins, the users collection inserts a new record with their email and related data to the accounts collection also. Basically there would be two records in users collection for that User now. One is their original email id record that got inserted now when the logged in (eg: abc#abc.com) and their old imported account (eg: abc#abc.com_TEMP). The reason why I wrote the code to call the API in the HOME page only is because, after User logs in, they will be redirected to the HOME page. So thought it won't be necessary to write the code globally or somewhere else.
So, if the above API response says that there's an old account that exists, I display a warning popup to the User saying that there's an old account existing in the database and asks whether they want to link that old account. If the User presses YES button, I make an API call to /api/link_old_account. In this API route, the code is written to perform this:
if there's a _TEMP version email of the currently logged in user in users collection, find the respective record _id that has mappings in the accounts collection.
then change the value of the userId field of that respective record(currently logged in user id) in accounts collection, with the user id of the record with the _TEMP version email.
then delete the record with the _id of the currently logged in user
then update the email field by removing the _TEMP from it
then deletes the records that matches the currently logged in user in the userId field of sessions collection. So that the currently logged in sessions of this User would be invalidated.
then redirects the user back to the HOME page using res.redirect(307, '/')
The solution seems to be working fine so far.

Auth0 database and social connections, unique email addresses

Maybe I am missing something here, or this is a flaw in Auth0? I'll give an example of my issue:
Let's say I have my Default App (client), hooked up to that I have Username-Password-Authentication (database connection) and google-oauth2 (social connection).
A user comes to my site, signs up via google-oauth2 (social connection) using joe#gmail.com. Once complete, he gets added to my users in Auth0, all great.
A few months later, Joe comes back to my site, and being a busy guy, he forgets he signed up to my site before. This time, he decides to sign up using my custom Email and Password form, that will add the user to the Username-Password-Authentication (database connection). so he signs up there using joe#gmail.com again, and everything goes well, he is now listed in my user's section in my Auth0 dashboard.
This is the problem, I now have two joe#gmail.com accounts, one with google-outh2 and one with Username-Password-Authentication. I really can't have this, I need a unique email address, regardless of the ID Auth0 supplies.
Does anyone know how I can make email address in my user section 100% unique? I'd think a rule would do this, but it appears rules only apply AFTER a user has been registered, so I can't run a rule before adding?
the only way I can see doing this right now is make my own checks and delete via the management API, but that is a really long and messy way to do it I feel.
Any help will be appreciated here!
Thanks!
Auth0's default behavior is to create a new account in the database for every unique entry. Since the user created using Google has a unique id (based on google-oauth2), and the user created using the sign-up form has a unique id - they will technically be considered two separate accounts. In order to resolve this disparity, you can establish a means with which the account data can be merged. In the documentation linked provided above, there are examples of three possible ways of doing this:
Automatic Linking - which involves creating a specific rule to merge users based on matching emails
User-Initiated Linking - which involves providing a UI for users to opt into merging users with matching emails
Suggested Account Linking - which involves setting up a rule that is linked into the UI
One important thing to consider is that the data returned from different social identity providers may not be normalized the way that data is normalized onto the Username-Password-Database. For example, while auth0's default for emails is to lowercase the information, google-oauth2 may return emails as Uppercased - creating the potential for non-matching emails when checks are made using strict equality
The option you are looking for is called account linking.
You can find more info at https://auth0.com/docs/link-accounts

External Login Account vs. Native Login Account

I am brand new to Visual Studio 2012 and MVC 4, and I've been working with the SimpleMembershipProvider via the WebMatrix.WebData library.
I'd like to integrate Facebook as an external login source down the road, but it's not a requirement as of right now. However, to get a decent feel for what it would take, I've been following the tutorial and guide found here - http://www.asp.net/mvc/tutorials/mvc-4/using-oauth-providers-with-mvc.
My question :
If a user has already been created using :
WebSecurity.CreateUserAndAccount(model.Email, model.Password);
WebSecurity.Login(model.Email, model.Password);
Can they be "upgraded" to an oAuthMemebership account in the future, if they choose to use their Facebook credentials instead of the email and password they created when first signing up?
I couldn't find a clear answer to this question in the guide, or elsewhere, so I'm hoping someone can clarify how that process may work.
The SimpleMembership setup allows for a local and multiple OAuth logins all sharing the same UserProfile - so a single user can login with either a local password, or FacebOogLiveWitter.
(I should state, that I'm assuming in this answer that the OAuth provider does not send back a matching piece of information for a local account. If they do then the principles of actually performing the merge are the same, but the complexity and steps are vastly reduced.)
The OAuth registration process will refuse the user if they use an existing user name, rather than try and merge two accounts. Therefore this isn't simple, you'll have to build the functionality yourself. The process is complex as there are many directions the user can approach this from (so you could simplify by only supporting one or two), and you need to enforce security as well in case someone tries to merge into an account they don't own.
I will assume you are comfortable with the link you've posted, and you've followed the Facebook help at (for example) Facebook Login and The Login Flow for Web (without JavaScript SDK) so you have a working test application.
Your general process has to have multiple user journey approaches to make sense to a user:
for a logged in user (with a local account)
let them login to facebook and associate the accounts
let them merge an existing account on your site which uses a facebook login
for a logged-in user (with a facebook account)
let them create a local account
let them merge an existing local account on your site
for a non logged in user who tries to register a local account
let them merge this new account with a facebook login that is already registered, and do that as part of the registration process
for a non logged in user who tries to register (or log in for the first time with) a facebook account
let them link this with an existing local account as part of the registration process
etc.
ASK PERMISSION
(You can skip this if the OAuth provider has sent back a matching identifying piece of information, such as an email address).
You should enforce confirmation security, usually through email confirmation sent to the target account of the merge. Otherwise:
someone can login to your site with facebook for the first time
during that process say they "own" the email address or username of a local account (remember, facebook won't necessarily confirm what their email is for you)
and therefore gain access to the existing local account
So, once the merge "request" is made, you need to ask for permission to proceed from the target account of the merge.
The MVC 4 AccountController
I will use Facebook as our OAuth example. To compare what happens when you register a user on your local authentication framework vs. OAuth:
Local: creates an entry in webpages_Membership and an entry with the same UserId in UserProfile (assuming you are using the default tables for the MVC 4 application template)
OAuth: creates an entry in webpages_OAuthMembership and an entry with the same UserId in UserProfile
Now let's look at what happens when a user signs in using Facebook for the first time:
They click on Login using Facebook (or whatever your button says)
they get taken to facebook to login
they succeed (let's assume that, and ignore the failure case)
they then get sent, invisibly to them, to /Account/ExternalLoginCallback
OAuthWebSecurity.SerializeProviderUserId is called, passing the OAuth details to that Action
They get redirected to /Account/ExternalLoginConfirmation and asked to provide a username for their new presence on your site
If that user name is available then UserProfile and webpages_OAuthMembership entries are created
This process is your chance to "join" the accounts by matching some unique piece of information. As long as you end up with the same UserId in UserProfile, webpages_Membership and webpages_OAuthMembership you should be ok. So we have to intercept the process at the point of /Account/ExternalLoginConfirmation.
If the OAuth provider has sent back a matching identifying piece of information, such as an email address, this becomes simple, test for this in the ExternalLoginConfirmation action, and auto-merge using a similar process to the one outlined below.
However, I think you can't/shouldn't assume that the user uses the same email address for your site and OAuth, (nor should you for many reasons). Also, probably in the T&Cs for something like FacebOogLiveWitter it stops you asking for the email of their account anyway, and if they don't currently they might in future.
So instead, you could link the accounts based on alternatives, like username or email address, or phone number. Either way you are going to need them to input some identifying piece of information that is unique against an account, and will pull back the target account.
Wrapping up
So to put this all together: In the first part of this answer I outlined how you will need to consider multiple user journeys to merge accounts. I will use the example 4.1.
Your process will need to:
(Assumption - when a user first registers with a local account, you ask them for an email address and validate it or assume it is valid)
Let the user login with facebook for the first time
at Account/ExternalLoginConfirmation ask them if they want to
Create a new account with you
Use their facebook login to access an existing account
Assuming the latter, then you log a request in a new table (maybe "MergeAccountRequests") with:
The facebook account UserId
The target merge local account UserId
An authorisation code to use in the email you need to send
(From this point on, if they login without confirming that merge, they will have to get sent to a page to ask them to confirm, rather than create objects in other db tables which you have to worry about later)
You then send an email to the address of the target merge (local) account asking for permission to complete the merge (a standard confirmation email, with a link)
When they click on that link, or enter the code you sent them (you could use SMS as well as email) then you need to merge the two accounts
Choose the "new" and "target accounts (in this case "new" is the facebook account as you don't have data associated with it yet)
Delete the UserProfile of the "new" account
Change the UserId of the "new" account webpages_OAuthMembership table to the same as the "target" account
Log the user out (so there are no complications depending on which account they are currently logged in with)
Display a message to the user telling them the merge is almost complete and that they can now log in with either account to confirm and complete the merge
Rather than send them to a login page, i would give them the login options alongside the confirmation message.

Users management strategies with LightOpenID

I've discovered recently LightOpenID wich i'm going to use as a login system for all my next websites.
As i'm fetching some infos when users register/login with LighOpenID, I'd like to know if it's technically ok to use user's email as unique id in my USERS table or if it's a bad idea ?
Thanks guys ,
FX
Thinks to consider:
It isn't mandatory to have an e-mail account linked to your OpenID account.
If there is an e-mail address, you are not guaranteed to get it back from the server, even if you ask.
Even if you get the address, you'd still need to validate it (e.g., by sending an e-mail message with a random token).
Users will probably own more than one OpenID identifiers (you are in such situation as soon as you open accounts at some major services like Google or Yahoo). Some of them will share the same e-mail address, some will not, and some will not even have an e-mail address set.
When the user changes his e-mail address behind the scenes, he'll lose his account at your site.
Using the e-mail as key does not really offer any advantage I can think of.
My advice is that, if you want to use OpenID, you should do it right. Read the OpenID URL from $openid->identity() after successful validation and use that to identify the user.
Additionally:
Keep in mind that URLs can be long; don't try to stuff it into a VARCHAR(100) column.
You might want to implement linked identities as Stack Overflow does.
It depends on your service. Normally, every email-adress is only assigned to one person. If multiple accounts per user are not wanted, it's ok.
Some families have a family-email-adress. But I guess they would also use the same account.
Why don't you take the OpenID as the unique ID? OpenIDs are unique and you get the OpenID before you get the Email-Adress, if you use only OpenID for logging in.