How can i access the jwt token payload - jwt

I have various microservices, and i am usign jwt policy to authenticate the user in express gateway, but i need to access the token payload, and proxy the payload to my microservice. I have tried to acces the payload in req.user, but is nothing there. Is there a way to access the payload?. thaks

When Express Gateway receives the JWT, it will verify its signature but it won't forward its content by default.
Instead, it will extract some of the contents and put these as headers that your service can then read and do the stuff you need.
In case you need a particular field, you can use the header policy to put these into the final request object.

Related

How to pass a parameter from a URL to an auth0 hook or rule for a machine-to-machine JWT?

I'd like to add a custom claim to a JSON web token generated by auth0 for machine-to-machine authentication. Like
color:blue
but I want to make blue a parameter I can pass with my request to auth0 for the token.
I ask for the token like this:
POST https://mydomain.eu.auth0.com/oauth/token
with a request body
{
"client_id":"myID",
"client_secret":"mySecret",
"audience" : "https://mydomain.eu.auth0.com/api/v2/",
"grant_type" :"client_credentials"
}
I see from How can I add claims to a JWT assigned with auth0 for a machine-to-machine application type? how to use a hook or rule to add a fixed claim, but I want to add a variable something like
?color=blue
to my request URL or request body and have that accessible from my hook code to be added as a claim.
Is that possible, please? How?
When you process an authorization request with a custom rule you get access to at least a part of the request properties by the request object of the context function argument. I tried it out but unfortunately the fields of the request object seem to be limited to only a few fields of the original request.
If your user information resides in Auth0 you could check out writing preferences into the user's metadata by using the Auth0 metadata API. This works well. But you will be able to only set metadata after the user has logged in, not before. Also you'll have to deal with two different Auth0 API endpoints now.

Authorizing access to resource in a REST API

I am new to building API's and I am having trouble understanding how to perform the following task reasonably.
There is an endpoint:
/user/{user_id}
which retrieves the details of the user.
The frontend code will request this endpoint to get details about the user to display on the dashboard.
I have to protect this endpoint so that a user who doesn't represent this user_id, emulates the request to get information about other users.
Since REST based API's are sessionless, I cannot store session keys. So how do I make sure that the server sends the user information only if the owner of the user id has requested it?
You are right. HTTP is a stateless protocol, therefore REST inherits that quality too.
Here is the deal in simple words.
[REST client] -------> [API endpoint]
You have many REST clients, and you need to make sure that only authorized users will grant the access to your API endpoint. One solution as #James suggested is use a token mechanism such as JWT https://www.rfc-editor.org/rfc/rfc7519.
If you consider JWT authentication, the process flow will be as follows.
[REST client] -------> [AA service]-------> [API endpoint]
You will need an AA(Authorization, Authentication) service in the middle. For example in a microservices approach, this can be performed from a API gateway which is a gateway to all of your services.
Client will give AA service their username and password. In exchange AA service will give the client a JSON token signed only by the server so that the confidentiality is protected. This token contains 3 things.
Header which specifies the type of token and algorithms used to sign it
Payload which includes claims like to whom the token is issued, when should the token expire, what is issued user's role should be etc. (see https://www.rfc-editor.org/rfc/rfc7519#section-4)
Signature which a product of unsigned token signed by the server key
Then you encode each header, payload, signature with base64 and concatanate with a ".". You now have a JWT.
AA service returns this JWT in exchange for credentials.
Client should store this token securely (ex: local storage) and the communication medium should be encrypted(ex: TLS). See https://stormpath.com/blog/jwt-the-right-way#how-to-secure-jwt , https://www.rfc-editor.org/rfc/rfc7519#section-6
After that for every subsequent REST call, client should include the received token, preferably in the Authorization header although it is technically possible to send the token in the message payload as well.
Then it is AA service's responsibility to decrypt the token using its signing key evaluate claims in the JWT and act upon whether to authorize the API call send him HTTP 401,403 responses.

How to download a file secured with IdentityServer

I want to be able to download a file from an API call. For argument's sake, let's say it's an automagically generated PDF file.
I have two problems:
Anchor tags can't add Authorization headers to the request, only XHR can.
XHR requests cannot download files.
My solution is to write my API with an [AllowAnonymous] end point in it, which takes the access_token as a parameter. I then validate the access token by hand and return a 401 or stream the PDF.
Is there a better solution than this or, if this is the best solution, how do I validate the access_token within the API?
This approach is totally fine.
If you want to use middleware to validate the token - it depends which middleware you are using. The plain Microsoft JWT bearer middleware has some events you can implement to retrieve the token from a query string alternatively.
The identity server token validation middleware has a TokenRetriever property which also allows you to retrieve the tokens from multiple/alternative locations.

Is it secure to send authentication token in HTTP/S response body?

In order to put some additional Information about the access- and refresh-token in a REST API response, I thought about creating a token object, that carries all the information which I want to append to the token and send it along with the usual JSON response.
Would this be less secure? If yes, why and how could I work around the security leak?
Well its possible to decrypt SSL traffic using Wireshark. You should encrypt your access token before sending it to the client in api response

Tracking consumers for RESTful API (no auth)

Folks,
What is a simplest way to track consumer applications accessing RESTful API services inside department.
We do not restrict access - no authentication/authorization - open for invocation, trusted environment.
No tools like OAuth AuthZ servers or API management yet... but might be heading there at some point.
For now we thought to request consumers just to include some custom HTTP Header like X-Client-Id and log it on the server side for stats etc..
But knowing that in the future we might want to switch to more standard ways of doing things ... what would be best alternative to have to change less code in the future ?
Have the "clientId" in the Authorization: OAuth token (like access token)
Have JWT token in the Authorization header (looks too much - signing,base 64 etc for simple client id tracking ...)
Any ideas would be appreciated
We recently implemented this for one of our REST platforms and we used a combination of BOTH the points you mentioned, meaning Authorization header & JWT token. Although, JWT is ONLY for authentication and GETTING an access_token (oauth token) which is later used with calling actual resource apis. I will discuss how we handled this situation and you can decide on how you want to implement it.
1) Authentication
Client sends a JWT to your authentication service (/api/oauth2/auth). (If you want more reading on JWT, you can read here and here of how JWT is implemented by google and how you can use spring-security-jwt libary to handle all the signing and encrypting/decrypting). You get the "clientId" out of JWT after decrypting and verifying the signature and after server does all the authentication, you respond back with a 'refresh_token' and an 'access_token'. Server will save the access_token as well and map it to the clientId so that when client makes requests using access_token, you can know which client is making the request. The access_token expires in some time (ideally in an hour) and when it expires, the client uses the 'refresh_token' to get a new access token by posting refresh_token to some refresh token url (/api/oauth2/auth/token)
2) Authorization
Client takes the 'access_token' and uses the access token to make all the subsequent requests on all other apis (/api/*). Ideally, the access_token is sent as a part of the "Authorization" header. Server uses request filters (if you are using JAX-RS, you can use something like ContainerFilterRequest to add filters to specific url patterns and intercept them) to filter EACH request and parse out the Authorization header value. You will get the access_token from the header and from the access_token you can get the clientId that you mapped in step 1). You can do other authorization logic in the security filter and if everything goes through, you can use this information to LOG that clientId and the request that the client made.
This way you can kill 2 birds with one stone : Implement a security layer & log the information about customers (what calls they are making, how many time etc. etc.). In case you don't want to implement security filter just yet (as you mentioned it might be in the future), for now, the clients can just pass on the "clientId" (base64encoded or not, upto you) as a part of "Authorization" header. If all the calls are from a "trusted" network, it should be ok, although not as secure. This way, when you ACTUALLY implement a JWT and Oauth based security layer, all you have to do is change your ContainerFilterRequest logic to parse out access_token instead of client id (as mentioned in step # 2).
I hope this helps ! For more information on security filters you can have a look at this answer: Basic Authentication of a resource in Dropwizard. It says dropwizard, but it mostly talks about JAX-RS.
To implement full AuthN/AuthZ layer for consumer tracking would be an overkill for now.
We thought to use either to Authorzation header to pass custom client_id token:
Authorization: Custom <Client_Id>
or to use some limited version of JWT (no signatures as there no intent to validate them)
as access token
Authorization: JWT <JWT>
Where JWT could be:
{"alg":"none","typ":"JWT"}
{
"iss":"Client_ID",
"aud": REST Service URI,
"iat":1328550785
}
I do not see description of access_token format in the specification https://datatracker.ietf.org/doc/html/rfc6749#section-1.4
Are there any contraints to use JWT as access token?