I have a webapp which lets the user OAuth 2.0 to youtube & after exchanging the authorization code I can capture the access_token & refresh_token into my database .
Can these tokens be maliciously used later by me , say after 2 weeks , to delete the poor user's video using /yoube/v3/delete or some other operation like insert badly formed captions ..
& if this could be done isn't this a security breach cause the poor used who has accidentally consent ouath into my application & got his access_token & refresh_token & other info captureded by my back-end
So basically when someone consents ouath's to an application ...the user is now on the mercy of the application...like information could be stored or deleted or anything
If yes? what can the poor user do to unlink & how would the user even know that video's are getting deleted by someone else ?
Access tokens are short lived tokens which will work for one hour after that time you will need to use the refresh token to request a new access token.
Your refresh token should not expire except.
if it has not been used for six months.
If a user authenticates your application they get a new refresh token, If they authenticate your application again then will get another refresh token. You can have up to 50 outstanding refresh tokens all will continue to work until you go over that number then the first one will expire.
The user can also revoke your access though their account at any time.
Don't bother storing the access token just store the refresh token, and make sure that if your user authenticates your application again that you replace the refresh token in your database with the new one.
If a user grants your application offline access which will give you a refresh token. Yes they are at the mercy of your application which can do what ever you have been granted access when ever.
Note: it can take a while to go through the verification process with the YouTube API start early.
We have built an app that asks for access to the YouTube API. We are not authorized yet, but are using it with our own accounts. We have the following problem:
While some of our Gmail accounts grant us access, some others fail even though on their third party security settings, you can see that they have granted us access. It seems that they have removed us from their lists, even though they haven't and we know that since these are our accounts.
Has anyone seen something like that?
Is getting our app authorized going to solve this?
Is there any other solution that you could offer?
Thanks for taking the time
my error message
status code: 400, response { data: { error: 'invalid_grant', error_description: 'Token has been expired or revoked.' } } }
Token has been expired or revoked.
Normally means that the refresh token you are using is no longer valid and you need to reauthenticate your user. The easiest way to test if i am right is to do just that force a reauth on the user.
causes for refresh token experation.
Refresh tokens while long lived they can expire for several reasons.
The user goes into their google account and revokes your applications access.
The refresh token hasn't been used in a while normally 3 -6 months google will automatically expire it.
You have reached the maximum number of outstanding refresh tokens for a user the oldest one will be expired.
It can also be related to the time on your system being out of sync with NTP (note i havent seen this error in years)
Let me try and explain number three a bit more. When a user authenticates your application you are given a refresh token. When the user authenticates your application again you are given an other refresh token. Both tokens will work as expected. You can continue this until you have up to 50 outstanding refresh tokens once you hit number 50 the first and oldest one will be expired. This is why it is important to always save new refresh tokens over the old one.
I know that (when using the authorization code "Authorization code" in OAuth), the lifetime of an access-token should be short but the lifetime of a refresh token can be long.
So I decided for my project:
access-token-lifetime: 1 day
refresh-token-lifetime: 30 days
But what is a typical lifetime of an authorization code?
Am I right that it should be really, really short?
Maybe like 1 hour or even only a few minutes?
I could not find any "best practice" for this..
All of this is standard but configurable i most identity / auth servers.
Authorization code
When the user consents an application accessing their data they are returned an authorization code. This code is only used its normally good for five minutes. anything lower than that would probably cause you issues with clock skew and there is really no reason IMO for it to be longer.
access token
Access tokens are returned after the authorization code has been exchanged. The access token. Access tokens are most often only good for 60 minutes.
Refresh tokens
refresh tokens are long lived tokens. The following are googles standard.
Refresh tokens are good for six months but this time is sliding.
If an refresh token has not been used for six months by an application then the access is revoked.
A user can also revoke the access as well at anytime.
depending upon the scope requested. Some refresh tokens expire after the user has changed their password
Again the above are just google standards. On the identity server I work on at work. I think the current settings is one month of non usage a refresh token expires.
Just found an answer on an other site:
The authorization code must expire shortly after it is issued. The OAuth 2.0 spec recommends a maximum lifetime of 10 minutes, but in practice, most services set the expiration much shorter, around 30-60 seconds.
Source: https://www.oauth.com/oauth2-servers/authorization/the-authorization-response/
It depends on the provider. For some providers, it works only once. Once you exchange the authorization code for access and refresh tokens, it will expire and you can't use it the second time.
I am working on a Google Drive App.
What is the lifetime of a Refresh Token? I have read that it lasts till until it is revoked. However, I also read somewhere that if your app is not used for 60 days, then the refresh token expires. Is this true ?
Also, who revokes the refresh token, is it the the user or in my case Google itself after a certain period of time?
I've not heard of a refresh token expiring after 60 days inactivity. Do you have a link that claims so?
The token can be revoke by the user or by your application.
I think, as per my study for the google drive file access using the refresh_token. The refresh token stays for around 6 months and then it we have to revoke it at that time when it gets expired. Google api's documents are nice and easy bit somehow lacks the way to use it.Just a thought, and once stuck got to search many place and less response to issues.
Facebook's deprecation of the offline_access permission is coming May 2012 and the documentation isn't giving us enough information on how to handle it.
We have an iOS app and corresponding service that powers it and integrates with Facebook in a deep way to leverage a user's friend list within out app (so if your FB friends are also using the app you can more easily connect). This is like how all social apps seem to work, so nothing special here.
Client
Our app uses Facebook iOS SDK to allow user to login, which we currently ask for offline_access. The token is persisted in our iOS app, but also sent to our server where it is saved. The client acts on behalf of user to post updates to a user's newsfeed (we also ask for publish_stream permission).
Server
Our server periodically checks to see if user's FB friends are now using our app. Next time user signs in, we expose content and relationships in a certain way to promote that user's friends. The server also acts on behalf of the user to periodically connect to the graph API and get the user's current friends list. This is so we can account for changes in a user's relationships and have them reflected in our app. We do this when the user isn't currently using the app so they have the best experience the next time they do use it. To enable this, our iOS app sends the access token to our server which it uses and why we ask for offline_access.
Note: If user signs out of our app explicitly, we delete the access tokens from both client and server.
Problems
Now that there is no longer a perpetual access token we can use, I'm trying to figure out the best practice for still enabling our scenarios while leveraging facebook's new intended way of handling and extending access tokens. The documentation is unfortunately not totally helpful.
Questions
A. When you authenticate through the newest Facebook iOS SDK, what is the default lifetime of the access token you get? This document says an extended token request will give you one that lasts 60 days. This other document talks about the first access token request and mentions varying validities but it's unclear and does it talk about specific validity times:
(emphasis is mine)
When you obtain an access token from Facebook, it will be valid
immediately and usable in requests to the API for some time period
defined by Facebook. After that period has elapsed, the access token
is considered to have expired and the user will need to be
authenticated again in order for your app to obtain a fresh access
token. The duration for which a given access token is valid depends on
how it was generated.
There are also events which may cause an access token to become
invalid before its expected expiry time. Such events include the user
changing their password, an application refreshing it's App Secret.
Dealing with varying access token expiry times, and handling the case
when an access token becomes invalid before its expected expiry time
is essential for building robust social experiences.
B. For the client, now that the access token isn't necessarily long lived, is the right approach for us to:
Let use login through FB, then detect whenever the access token is expired. If it is, then call into FB iOS SDK to re-authentication/re-authorize? (this should just trigger user to bounce out to FB iOS app, and in most cases come immediately back to our app with a new access token).
C. According to this blog post I found, you can only extend an access token once:
Can I exchange my 60 day access token for a new 60 day access token?
No, sorry you cannot. You can only exchange a valid (meaning current)
user access token for an extended one. You cannot extend an already
extended access token.
On the client, I can just handle this by prompting a re-authentication/re-authorization as I mentioned in Question B. However, this doesn't work on our server. We could certainly have the server renew it once to 60 days, but what happens on the 61st day? The server just stops being able to sync the friend's list?
D. It seems to make sense to check the validity of the FB access token every time the app starts or re-hydrates from sleep. What is the best way for our iOS app to check this? Is there a recommended endpoint to call to validate a token? Should we just call into https://graph.facebook.com/me passing the access token and checking the response?
Note: we can certainly record the expires time when we get the initially extended token, but this isn't reliable since the user could revoke our app's permission anytime which makes the expires time an unreliable data point on validity
Overview
I believe that the root of what facebook is trying to achieve is to prevent an app from having perpetual ever-lasting access to a user's account. So, with the new migration an app can only access an account for 60 days unless the user signs in again.
I don't work for facebook, but here are my findings from playing around with the facebook graph api.
General Solution
Whenever a user signs in, take their access token and immediately extend/refresh it, and save it
Record the expiration date of the access token
When an access token expires (either from the recorded date, or a graph API exception telling you so), then notify the user that you don't have access, and ask them to sign in again.
Answers
A. When you authenticate through the newest Facebook iOS SDK, what is the default lifetime of the access token you get? This document says an extended token request will give you one that lasts 60 days. This other document talks about the first access token request and mentions varying validities but it's unclear and does it talk about specific validity times:
Here's how it works:
The first sign-in grants you approximately two hours
By refreshing the access token, you can get up to 60 days
If the user doesn't sign in to those 60 days, there is no way to get access for longer without having them sign in.
If the user de-authorizes your app, that 60 day windows ends immediately, and you will no longer have access.
B. For the client, now that the access token isn't necessarily long lived, is the right approach for us to: Let use login through FB, then detect whenever the access token is expired. If it is, then call into FB iOS SDK to re-authentication/re-authorize? (this should just trigger user to bounce out to FB iOS app, and in most cases come immediately back to our app with a new access token).
If the users access token is expired, your only option is to have them go through a login loop like you are talking about.
C. According to this blog post I found, you can only extend an access token once. On the client, I can just handle this by prompting a re-authentication/re-authorization as I mentioned in Question B. However, this doesn't work on our server. We could certainly have the server renew it once to 60 days, but what happens on the 61st day? The server just stops being able to sync the friend's list?
You can only extend an access token once. On the 61st day, you are out of luck. Best notify the user and let them know that unless they sign in, you won't be able to do anything.
D. It seems to make sense to check the validity of the FB access token every time the app starts or re-hydrates from sleep. What is the best way for our iOS app to check this? Is there a recommended endpoint to call to validate a token? Should we just call into https://graph.facebook.com/me passing the access token and checking the response?
I haven't be able to find an API equivalent of the Debug Console. This FB blog article talks about invalidated access tokens, but doesn't mention any API methods in particular meant to test the API.
I your suggestion of hitting https://graph.facebook.com/me would work just fine is exactly what they recommend in their example. In fact, I might use this approach in my app as a pro-active way of checking an access token.
Tid Bits
When you "refresh" an access token, a new access token will be returned. The response looks like: access_token=TOKEN&expires=5183912
You can only "refresh" an access token once. If you try to "refresh" the long-lived token returned from a previous call, it will return the same token, but doesn't throw an exception unless the token has expired. (in other words, you can safely try to refresh your token)
The default access token length seems to be around 2 hours
If you "refresh" an access token, that new access tokens seems to be the one that you'll get from the facebook API afterwards (instead of returning the original, short-lived access token)
Also, if you want to play around, these tools make it easy to test out your use case in a browser before burying it in your code:
Graph API Explorer - For creating and getting access tokens
Debug Console - For checking the expiry date of tokens before/after refresh
Refresh Endpoint - For manually testing extending your tokens
Great answer, one important addition : the default token lasts between 1 and 2 hours. You get the remaining of the hour during which the user signs up, plus 1 full hour. For example if a user signs up at 3:45pm, the access token will expire at 5pm. To be safe developers should assume it only lasts 1hour.