OAuth client credentials concept - oauth-2.0

I just have a question re client_credentials grant type in OAuth 2.0. When a client requests for an access token 2 times, will the access token requested on the first time be invalid?
Thanks!

The first obtained access token will be valid until it expires.
A token contains an authentication ticket including the indentity and an expiration time. When the token is decrypted, the server obtains the ticket and checks that the ticket is not expired. It uses the claims included in the ticket for authorization tasks.

Related

Why RefreshToken received form azure active directory is not in JWT format

I need to understand why refresh token issued by AAD is not in JWT format( i used Auth Code grant type for generation of refresh token). It looks something like as follows 0.ATYAoWHs1YRqUk-OAYpDkwKjaYAEJhrbDpBNmWw7q0NZVas2APk....(rest of the token).
Also if we can get this refresh token in JWT format then how can we do that.
Thanks
Abhishek
It isn't in JWT format because it does not need to be.
A refresh token is data that you send to the identity provider to get new access tokens.
It should not have any other meaning for your application.
Store it securely and send it to AAD when you need new tokens.
Then take the new refresh token you get in the response and overwrite your previous refresh token with that.
The OAuth 2 RFC also talks about it https://www.rfc-editor.org/rfc/rfc6749#page-10:
A refresh token is a string representing the authorization granted to the client by the resource owner. The string is usually opaque to the client. The token denotes an identifier used to retrieve the authorization information. Unlike access tokens, refresh tokens are intended for use only with authorization servers and are never sent to resource servers.

Does oauth issue a new token every request?

If you request a token from the server (with the same credentials and within the lifespan of an old token) should it either:
return a fresh token every time
return the same token with a shorter lifespan
something else / depends on
Is it depending on whether you use a refresh token?
Can you please reference the OAuth 2 RFC in your answer ?
The OAuth 2.0 Authorization Framework is a framework that allow a Resource Owner to CONSENT to allow DELEGATION of their permissions to access a Resource Server to another party (OAuth Client).
The Authorization Request is performed by the OAuth Client and is fulfilled by the Authorization Server only after obtaining CONSENT from the Resource Owner by the Authorization Response (which includes a Access Token).
The Access Token is a Bearer Token with a limited lifetime.
The refresh Token, if used, by the client to requests a new access token by authenticating with the authorization server and presenting the refresh token. The client authentication requirements are based on the client type and on the authorization server policies.
The "same" Access Token is never returned or reused by the Authorization Server.
Reading and following the Security Considerations with any Authentication or Authorization Protocols is a must. Most breaches are caused by implementation errors rather than protocol errors.
You should Tell us what you have tried and show logs or results and Read:
https://stackoverflow.com/help/how-to-ask

How to determine identity token expiration in oidc-client

I am working with Identity Server 3 on the service and oidc-client.js in my front end. The client setup in Identity Server does not set the token lifetime options, so should have the default values of 300s (5min) for the identity token lifetime and 3600s (60min or 1hr) for the access token lifetime. My client app requests and receives both an identity token and an access token. The oidc-client user object exposes expiration information about the access token. But how can I tell when the identity token has expired? Or maybe more to the point, which token should represent a still valid login/authentication? My code is currently using the user object expiration data to determine if a user is authenticated, but now that I realize that's the access token expiration, I'm not sure that's the right thing to do.
Same question asked another way: If a user logs in and gets an identity token that's valid for 5 minutes and an access token that's valid for 60 minutes, when does that user's authentication expire and how does the client app know it has expired?

Oauth2 assertion grant: Why no refresh token?

I'm looking into Oauth2 to allow developers to authorize users of their app to use my service. I've found a few sources that say that my Authorization Server should return an access token when a user sends an assertion (JWT in my case) but that it should not return a refresh token. I'm wondering what the harm is in returning a refresh token. Developers could invalidate refresh/access tokens by calling an Api that invalidates any access granted from a particular JWT's id.
That recommendation is not correct. Refresh tokens are optional and can be issued at the discretion of the Authorization Server after client presents the authorization grant. See Oauth2 specification
1.5 Refresh tokens
Refresh tokens are credentials used to obtain access tokens. Refresh
tokens are issued to the client by the authorization server and are
used to obtain a new access token when the current access token
becomes invalid or expires, or to obtain additional access tokens
with identical or narrower scope (access tokens may have a shorter
lifetime and fewer permissions than authorized by the resource
owner). Issuing a refresh token is optional at the discretion of the
authorization server. If the authorization server issues a refresh
token, it is included when issuing an access token (i.e., step (D) in
Figure 1).

Google Oauth "Service Account", how to refresh token?

I am using Oauth to access Google Cloud Storage via their JSON API.
All is fine, I authenticate and get an access token which has an expiration of 3600.
What is the correct way to refresh this?
It is my understanding that in other types of oAuth flows (i.e. Web Server), the initial authorization request returns a refresh token as well as an access token, and that the refresh token is used to ask for another access token when the current access token has expired.
But is appears that there is no refresh token when doing server-to-server oAuth with a Google "Service Account"?
Found the answer.
https://developers.google.com/accounts/docs/OAuth2ServiceAccount#expiration
Access tokens issued by the Google OAuth 2.0 Authorization Server
expire one hour after they are issued. When an access token expires,
then the application should generate another JWT, sign it, and request
another access token.

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