I am having some trouble grasping the role of the refresh token flow within modern SAML/OAuth/OIDC methods.
I understand that authentication is about proving a user is who they say they are, while authorization is about proving a user has access to any particular resource. I also understand that refresh tokens can be used to to handle both.
My question is, how does the refresh/access token flow fit within authentication/authorization methods like OAuth2.0 and OIDC? Is it a subset of these auth methods, or just an optional technique sometimes employed by them? Or are they unrelated to and are like comparing pineapples to oranges?
When it comes to building authentication into a system using the refresh token flow, it is not considered OAuth or OIDC unless if it is built to specifications defined here, correct?
edit: To be more succinct - OAuth seems like a "complete" authentication method. Is the refresh token flow also considered a "complete" solution alongside OAuth, or is it just a technique that is used within OAuth?
When the user has authenticated and got the access token, it will expire after a pre-configured time (e.g. 10 minutes). But to keep the user signed in longer than the expiration time, a refresh token can be used to request a new access token (e.g. valid for additional 10 minutes), and you typically also get a new refresh token.
In other words, the refresh token is a way to keep the "user session" alive for longer than the expiration time of an access token.
A refresh token typically have different security properties, e.g. it can typically only be used one time.
Working on a very basic React-Native App with a login-form, fetching Data from an API and display it. (Token based OAuth2 with Password Grant Type)
Question: When is the best time to retrieve data from my REST service again?
Currently I only fetch the data once, and that is when the user logs in.
Possible Solution: My idea would be to save the user data (username,password | token) in AsyncStorage (or SecureStorage) and to query it again every x minutes - Is that the normal workflow or do I have a major security gap?
I did not include any code, because it is a question of understanding and I shouldn't have any problems with the programming part.
Storing user password is a big NO.
If your server is using standard OAuth2, normally the sign in response would include an access token and a refresh token. See the standard doc.
The access token is embedded in the app's requests to the resource server in the session.
The refresh token is used to retrieve a new access token, either when the current access token has expired, or when a new session is started. So this refresh token is what the app should save, across sessions.
The refresh token's lifespan should be reasonably long such that the client, in this case your app, doesn't have to worry about redoing user sign in.
I am using client-flow authentication in Xamarin.Forms and am trying to figure out how to handle when an authentication token expires.
My Code:
Upon initial login, the user logs in with the native Facebook SDK and I pass the access_token to MobileServiceClient to get back an authenticated user.
var user = await client.LoginAsync(MobileServiceAuthenticationProvider.Facebook, token).ConfigureAwait(false);
I then save the user's UserId and MobileServiceAuthenticationToken in local settings (using the Xam.Plugins.Settings plugin).
The next time the user opens the app, I set the user from settings and skip manual login:
if (!string.IsNullOrWhiteSpace(Settings.AuthToken) && !string.IsNullOrWhiteSpace(Settings.UserId))
{
client.CurrentUser = new MobileServiceUser(Settings.UserId);
client.CurrentUser.MobileServiceAuthenticationToken = Settings.AuthToken;
}
My Question:
This works great. However, I know that the MobileServiceAuthenticationToken has an expiration on it. What will happen in my app when the expiration date is reached? How do I refresh the token without requiring the user to re-log-in to Facebook? I have tried the MobileServiceClient's RefreshUserAsync() method, but I get the following exception:
Microsoft.WindowsAzure.MobileServices.MobileServiceInvalidOperationException: Refresh failed with a 400 Bad Request error. The identity provider does not support refresh, or the user is not logged in with sufficient permission.
Is there a way to test this? (since the token expiration is 3 months from now.) Thanks for the help!
Microsoft.WindowsAzure.MobileServices.MobileServiceInvalidOperationException: Refresh failed with a 400 Bad Request error. The identity provider does not support refresh, or the user is not logged in with sufficient permission.
Since you are using client-flow authentication, you could not use RefreshUserAsync() for refreshing the MobileServiceAuthenticationToken. Your mobile backend does not cache the related access_token and refresh_token for renewing the authentication Token.
Is there a way to test this? (since the token expiration is 3 months from now.) Thanks for the help!
AFAIK, the MobileServiceAuthenticationToken expiration is one hour by default, you could use https://jwt.io/ to decode your token and check the exp property, then use https://www.epochconverter.com/ to convert your timestamp to human date.
For your requirement, you could follow adrian hall's blog about Caching Tokens and refer to the IsTokenExpired method for decode your authenticationToken and check the exp, then manually renew the authenticationToken.
Per my understanding, there are two approaches for you to achieve your purpose:
You need to cache the facebook access_token in your mobile client side, after you manually checked the authenticationToken and found that it expired, then you could manually execute the following code for renewing the token and explicitly update your local cache.
var user = await client.LoginAsync(MobileServiceAuthenticationProvider.Facebook, token).ConfigureAwait(false);
Note: Your facebook access_token has the Expiration Date, so if your access_token expired, then you need to force the user to log into Facebook again before acquiring the new authenticationToken.
Or you could build your custom endpoint for refreshing the authenticationToken and explicitly set a long lifetime for your new authenticationToken, details you could follow this similar issue. Note: For your client-side expiration processing, you need to renew the token before your local authenticationToken is about to expire.
I want to integrate with Miscrosoft Outlook. I am able to login with MSAL.js and get an access token, but I am not able to get a refresh token. Is there a way to do it?
I'll assume that since you're using the MSAL.js (https://github.com/AzureAD/microsoft-authentication-library-for-js) that you're using implicit flow for authentication and authorization.
Implicit flow doesn't support refresh tokens, but you can request a new token silently. This is done similarly to how you request the token (id or access) in the first place. Unfortunately, I haven't found that MSAL.js does this transparently and I've needed to detect expired tokens and request the new tokens in my code. You can read more about refreshing tokens here.
Alternatively, if what you're implementing allows you to use one of the other MSAL libraries (for example, the .Net one) then you can use one of the other OAuth flows that explicitly support refresh tokens.
I couldn't find any answer in the MSAL.js documentation, however this source code comment suggests you can renew a token manually by passing only the clientId as your scope to acquireTokenSilent.
To renew idToken, please pass clientId as the only scope in the Authentication Parameters
I use msal v1.4.0
I remove 2 keys in storage (see picture) then call acquireTokenSilent again to get new access token.
Code to remove those 2 keys:
const keys = Object.keys(sessionStorage).filter(x => x.indexOf('authority') > 0)
keys.forEach(x => sessionStorage.removeItem(x))
I'm referencing another SO post that discusses using refresh tokens with JWT.
JWT (JSON Web Token) automatic prolongation of expiration
I have an application with a very common architecture where my clients (web and mobile) talk to a REST API which then talks to a service layer and data layer.
I understand JWT token authentication, but I am a little confused at how I should use refresh tokens.
I want my JWT authentication to have the following properties:
JWT Token has an expiration of 2 hours.
The token is refreshed every hour by the client.
If the user token is not refreshed (user is inactive and the app is not open) and expires, they will need to log in whenever they want to resume.
I see a lot of people claiming to make this a better experience using the concept of a refresh token, however, I don't see the benefit of this. It seems like an added complexity having to manage it.
My questions are the following:
If I WERE to use a refresh token, wouldn't it still be beneficial to have a long term expiration for good practice on that token as well?
If I WERE to use a refresh token, would that token be persisted with the userId and/or JWT token?
When I update my token every 1 hour, how does this work? Will I want to create an endpoint that takes in my JWT token or my refresh token? Will this update the expiration date of my original JWT token, or create a new token?
Is there the need for a refresh token given these details? It seems that If the user is just using a JWT token to grab a new token (per the link above) then the refresh token is obsolete.
Let me come to your questions a little later down the line and start by actually discussing the whole purpose of a refresh token.
So the situation is:
The user opens the app and provides his login credentials. Now, most probably the app is interacting with a REST backend service. REST is stateless, there isn't a way to authorize access to the APIs. Hence, so far in the discussion, there is no way to check if an authorized user is accessing the APIs or is just some random requests coming through.
Now to be able to solve this problem, we need a way to know that the requests are coming from an authorized user. So, what we did was to introduce something called an access token. So now once the user is authenticated successfully, he is issued an access token. This token is supposed to be a long and highly random token (to ensure that it can not be guessed). This is where the JWT comes into the picture. Now you may/may not want to store any user-specific details in a JWT token. Ideally, you would want to just store very simple, extremely non-sensitive details in the JWT. The manipulation of the JWT hash to retrieve other user's details (IDOR etc.) is taken care of by JWT (the library being used) itself.
So, for now, our problem with authorized access is solved.
Now we talk of an attack scenario. Let's say using all of the above user Alice, using the app, has the authorized access token and now her app can make requests to all the APIs and retrieve the data as per her authorization.
Assume that SOMEHOW Alice loses the Access Token or put another way, an adversary, Bob, gets access to Alice's access token. Now Bob, despite being unauthorized, can make requests to all the APIs that Alice was authorized to.
SOMETHING WE IDEALLY DON'T WANT.
Now the solution to this problem is :
Either detect that there is something of this sort happening.
Reduce the attack window itself.
Using just the access token alone, it is hard to achieve condition 1 above, because be it Alice or Bob, it's the same authorized token being used and hence requests form the two users are not distinguishable.
So we try achieving 2 above and hence we add an expiration to the validity of the access token, say the access token is valid for 't' (short-lived) time.
How does it help? Well, even if Bob has the access token, he can use it only while it is valid. As soon as it expires, he will have to retrieve it again. Now, of course, you could say that he can get it the same way he got it the first time. But then again there's nothing like 100% security!
The above approach still has a problem and in some cases an unacceptable one. When the access token expires, it would require the user to enter his login credentials and obtain an authorized access token again, which at least in case of mobile apps, is a bad (not acceptable) user experience.
Solution: This is where the refresh token comes in. It is again a random unpredictable token that is also issued to the app along with the access token in the first place. This refresh token is a very long-lived special token, which makes sure that as soon as the access token expires, it requests the server for a new access token, thus removing the need for the user to re-enter his login credentials to retrieve a new authorized access token, once an existing one has expired.
Now you may ask, Bob can have access to the refresh token as well, similar to the way he compromised the access token. YES. He can. However, now it becomes easy to identify such an incidence, which was not possible in the case of an access token alone, and take the necessary action to reduce the damage done.
How?
For every authenticated user (in case of a mobile app, generally), a one to one mapped refresh token and access token pair is issued to the app. So at any given point in time, for a single authenticated user, there will be only one access token corresponding to a refresh token. Now assume that if Bob has compromised the refresh token, he would be using it to generate an access token (because access token is the only thing which is authorized to access resources through the APIs). As soon as Bob (attacker) requests with the newly generated access token because Alice's (genuine user) access token is still valid, the server would see this as an anomaly, because for a single refresh token there can be only one authorized access token at a time. Identifying the anomaly, the server would destroy the refresh token in question and along with it all, it's associated access tokens will also get invalidated. Thus preventing any further access, genuine or malicious, to any authorization requiring resources.
The user, Alice, would be required to once again authenticate with her credentials and fetch a valid pair of a refresh and access tokens.
Of course, you could still argue that Bob could once again get access to both refresh and access tokens and repeat the entire story above, potentially leading to a DoS on Alice, the actual genuine customer, but then again there is nothing like 100% security.
Also as a good practice, the refresh token should have an expiry, although a pretty long one.
I believe for this scenario you could work with the access token alone, making
life easier for your clients but keeping the security benefits of a refresh token.
This is how it would work:
When your user logs in with credentials (username/password) you return a
short-lived JWT. You also create a db record where you store:
JWT id
user id
IP address
user agent
a valid flag (defaults to TRUE)
createdAt
updatedAt
Your client submits the JWT in every request. As long as the JWT hasn't expired,
it has access to the resources. If the JWT expired, you refresh it
behind the scenes and return both the resource and an additional X-JWT header
with the new JWT.
When the client receives a response with an X-JWT header, it discards the
old JWT and uses the new one for future requests.
How refreshing the JWT works on the server
Look for the matching db record using the JWT id.
Check if the valid flag is still true, otherwise reject.
Optionally, you can compare the request IP address and user agent against
the stored IP address and user agent, and decide to reject if something looks
fishy.
Optionally, you can check the db record's createdAt or updatedAt fields, and
decide not to refresh if too much time has passed.
Update the updatedAt field in the db record.
Return the new JWT (which is basically a copy of the expired JWT, but with an extended expiration time).
This design would also give you the option to revoke all tokens for a user (for
example, if the user loses his phone or updates his password).
Benefits:
Your client never has to check expiration times or make refresh token
requests, all it does is check for an X-JWT header on responses.
You can add custom refresh logic based on IP address, user agent, max-token
age, or a combination of those.
You can revoke some or all tokens for a user.
If I WERE to use a refresh token, wouldn't it still be beneficial to have a long term expiration for good practice on that token as well?
Refresh Tokens are long-lived, Access Tokens are short-lived.
If I WERE to use a refresh token, would that token be persisted with the userId and/or JWT token?
It would be persisted as a separate token on the client, alongside JWT but not inside JWT. UserID/UID can be stored inside the JWT token itself.
When I update my token every 1 hour, how does this work? Will I want to create an endpoint that takes in my JWT token or my refresh token? Will this update the expiration date of my original JWT token, or create a new token?
Yes, you need a separate service that issues and refreshes token. It won't update the expiration of the existing JWT Token. A token is simply JSON field-value pairs that are base64 encoded. So changing the data, changes the output. The token also has the issue date, which will at the very least change on every fresh issue (refresh). So every token will be unique and new. The old tokens will auto-expire, hence you need expiration on all Access Tokens, otherwise they will linger around forever.
The other answer here states that old tokens get destroyed when you issue a new token. That's simply not the case. Tokens cannot be destroyed. In fact, you can harvest hundreds of tokens by constantly contacting the auth server and asking for new fresh tokens using your Refresh Token. Each of those Access Tokens will be valid till their expiry. So expiry is imperative, and it should be short.
Is there really the need for a refresh token given these details? It seems that If the user is just using a JWT token to grab a new token (per the link above) then the refresh token is obsolete.
JWT tokens have client claims. For example is_manager:true claim on a JWT token might allow access to manager-level features. Now if you decide to demote the user from manager to contractor, that won't take effect immediately. The user may still be using the old token. Finally when that expires, he hits the auth server to refresh his token. The auth server issues a new token without the managerial claim and the user won't be able to access managerial features any more. This creates a window during which the user's claims are not in sync with the server. This again explains why Access Tokens should be short-lived so sync'ing can happen often.
Essentially you are updating the authorization checks every 15 minutes, instead of checking them on every single request (which is how typical session-based auth works). If you want real-time permissions instead of every-15-minute refreshes, then JWT may not be a good fit.