Implementing a backend-less auth mechansim - amazon-web-services

I would like to implement an SPA which bounces the user to a login page, if not already logged in. It would then able to make a call to an API (not necessarily an API Gateway) hosted within an AWS VPC.
As I currently understand it, this would involve a front-end framework library authenticating the user via OAuth 2.0. It would then need to retrieve a token (allowed because of the auth validation) to call an API Gateway which provides access to the API hosted within the VPC.
Given this concept, is this architecture possible without the use of a Lambda?

If you are willing to use API Gateway in front of your API:
Yes, this architecture is possible without using a Lambda. API Gateway has integration with AWS Cognito User Pools for authorizing requests. You can find the AWS docs on how to set this up.
If you don't have an AWS API gateway in front of your API:
In this case you will have to implement one of the authentication and authorization flows provided by OAuth 2.0 standard. In this case, whether you would want to use a Lambda or not, is up to you and your back-end architecture.

Related

is ok to choose AWS HTTP API gateway for a mobile application?

I am trying to decide which aws apigateway version choose for my application (HTTP vs REST API gateway).
I am experimenting with AWS HTTP API gateway to see if it works fine for my use case.
These are my requirements:
The only client is a mobile application
The rest API can be accessed only from logged in users
I want to use cognito with cognito authorizer
My backend is a mix of lambda services and HTTP rest services exposed via an internal application load balancer
Everything seems to be supported, the only concern is that I would have used an api key, but this feature is not currently supported on HTTP API gateway.
Are there any security concern if I go for HTTP without any api key?
What would be the right way to restrict the access only to requests coming from my mobile app?
Everything seems to be supported, the only concern is that I would have used an api key, but this feature is not currently supported on HTTP API gateway.
HTTP APIs support OpenID Connect and OAuth 2.0 authorization
https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api.html
If you have any custom api-key, you can still have an authorizer lambda to authenticate and authorize the client.
Are there any security concern if I go for HTTP without any api key?
What do you mean by the api-key? API-key is usually static shared secret used mostly in the backend application. Claiming the users need to be authenticated and using the mobile app, having a hardcoded api-key is not the best idea (read - it is a terrible idea)
Under these requirements the default option is using OAuth2/OIDC for user authorization and passing the user's access token along the API requests.
What would be the right way to restrict the access only to requests coming from my mobile app?
I want to use cognito with cognito authorizer
The simplest and built-in way is using the access token from Cognito and built-in JWT API authorizer. Yet you may configure any other option.

Authenticate session with AWS API Gateway

Situation: I have an app (Next.js/React on Vercel) running on example.com. I have an api (AWS API Gateway) on api.example.com. Currently the application on example.com supports login using Auth0 as authentication provider.
Problem: I would like to be able to make authenticated requests from the application (example.com) to the api (api.example.com).
Architecturally, I was hoping for a way for the API Gateway (api.example.com) to handle the authenticated session from the app/Auth0 cookie (example.com). I thought the browser could share the cookie (since api.example.com is trusted) and the API could validate it.
But I don't see a standard way to do it. I think I could try to create some custom lambda authorizer for AWS' API Gateway. But since we're dealing with authentication, I would prefer to outsource as much as humanly possible and avoid any custom code. I just can't seem to piece together the way for API Gateway to handle the sessions, which I assumed would be a pretty common problem to solve.
Sidenote: Previously, I used the pages/api that's baked into Next.js to directly call Lambdas on AWS and expose them. With this, authentication natively works. That's the experience I'm now trying to recreate, but without the user having to take a roundtrip.
When you want to protect APIs it’s better to use JWT tokens to carry over necessary claims e.g. id of authenticated user. OpenID connect and Oauth2.0 are the standards to look into.
Auth0 has documentation of recommended authentication flow: https://auth0.com/docs/flows/authorization-code-flow
as well as example with Api Gateway’s HTTP apis: https://auth0.com/blog/securing-aws-http-apis-with-jwt-authorizers/
AWS documentation has more info about Http Apis and JWT token authorizers: https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-jwt-authorizer.html
If your Api gateway is using Rest apis instead of more light-way Http apis then token based Lambda authorizers are the right solution: https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-use-lambda-authorizer.html

authentication with Cognito pool per tenant

I am watching an AWS reInvent video: https://www.youtube.com/watch?v=kmVUbngCyOw&feature=emb_logo&ab_channel=AmazonWebServices where it suggests to use Cognito pool per tenant.
This is what the authentication looks like and introduces an Auth manager to Auth against Cognito and gets back a JWT token based on OpenIdConnect.
I was reading another blog post here: https://medium.com/#tarekbecker/serverless-enterprise-grade-multi-tenancy-using-aws-76ff5f4d0a23
and It suggested using a Custom Authorizer attached to the API gateway.
Am I right in understanding that we should basically be authenticating in 2 places ->
From the web app using Auth Service
At API gateway using custom authorizer
Generally, people use the AWS SDK to authenticate the user from Cognito and it handles the whole authentication logic. AWS-SDK is available in almost all popular languages.
As API gateway is the frontline service or the publically exposed service through which you can access the microservices hosted using Lambda. Also, ApiGateway interacts as an intermediary/broker service between any client application including Web and Lambda microservices.
Custom Authorizer is used for implementing the custom authorization logic at the API Gateway service i.e. if a user role doesn't have any access to certain Apis it'd just give an error to the user trying to access those resources.
For example how we used Custom Authorizer in the past. We had users with 2 role types
Admin
User
We had to restrict the access of the admin Apis. So we added all this logic to authorize access to the Apis based on the information we get in the bearer token.
https://aws.amazon.com/blogs/compute/introducing-custom-authorizers-in-amazon-api-gateway/

How to authenticate requests in AWS API Gateway securely with a web app

I'm trying to make an AWS API Gateway endpoint that can authorize my JWT.
This is not possible with custom (Lambda) authorizers because they require a signed Authorization header which requires an IAM User's AWS Access Key and secret. An untrusted source, like a web app, cannot keep secrets, so we can't bundle the Access key into the client-side app. Therefore, this custom authorizers aren't suitable for web apps.
The only way to implement authentication of a JWT in API Gateway is to implement the authentication logic into the Lambda function itself.
Does anyone disagree? Are there security flaws? Is this a misuse of API Gateway?
This question as been asked before here and here, but never adequately answered.
Please use Authorizer in API gateway for achieving this. There are multiple Authorizers possible in API Gateway.
https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-control-access-to-api.html

Using AWS API Gateway for Lumen based REST API Service with Passport authentication hosted in EC2

I am entirely newbie in Amazon Web services. Currently i am developed a REST API service using Laravel's micro frameworks called Lumen. I am using passport for token based authentication and all that working fine. I need a proxy server to hide my actual endpoints and do some other functionality so i am planning to use AWS API Proxy Gateway and host the API endpoints in EC2 instance.
i went through Build an API with HTTP Proxy Integration from Aws documentation. but there is nothing about using a custom authentication using Oauth.
My Doubts are
How to use Passport authentication when using AWS API Gateway
Is there any good method to hide my REST Endpoint from customer and need a way to change the proxy end point from time to time.
I don't know Laravel ecosystem, but:
if passport expose something like an OpenId Connect you could use Cognito Federated Identities for, precisely, federate your identity, and associate the authorized identities with a given IAM role and unauthorized with another role;
you can use an Api Gateway Custom Authorizer to perform fully customizable auth;
Try expanding your question so we could add more details...
Yes, like what BAD_SEED said, you can use API Gateway Lambda authorizer (formerly known as the custom authorizer) to do any logic to verify the token, since it's just a javascript package.
So, one option is like what auth0 does in (https://auth0.com/docs/integrations/aws-api-gateway/custom-authorizers/part-3) and (https://github.com/auth0-samples/jwt-rsa-aws-custom-authorizer). Their sample authorizer does followings:
It confirms that an OAuth2 bearer token has been passed via the Authorization header.
It confirms that the token is a JWT that has been signed using the RS256 algorithm with a specific public key
It obtains the public key by inspecting the configuration returned by a configured JWKS endpoint
It also ensures that the JWT has the required Issuer (iss claim) and Audience (aud claim)
But unfortunately, Passport does not support JWKS endpoint (which exposes public key for the token signature). So you may have to expose it by yourself.
Another option is much easier, you just make a token verification endpoint in your application, something like /users/me, and protect it with auth middleware. Then in your Lambda authorizer, call it with the token in the request to your other micro service endpoints. By this way, all token verification stuff is left to Passport, and the authorizer just executes policy based on the result of the verification.
Not very sure about what you want to reach, but API Gateway is just a proxy, so you can certainly change backend side endpoints for its frontend one, which is better not changing so often.