I'm building some RESTful API for my project based on Play Framework 2.X.
My focus is on the authentication mechanism that I implemented.
Currently, I make use of SecureSocial.
The workflow is:
An anonymous user calls a secured API
Server grabs any cookie Id (kind of authentication token) and checks for matching in the Play 2 cache. (cache contains an association between cookie Id (randomly generated) and the user Id, accessible from database.
If any matched, user is authorized to process its expected service.
If none matched, user is redirected to a login page, and when filled with valid credentials (email/password), server stores its corresponding authentication data on Play 2 cache, and sends the newly created Cookie containing only a custom Id (authentication token) to user and of course, secured through SSL.
While the cookie/token doesn't expire, the user can call secured api (of course, if authorized)
The whole works great.
However, after some search, I came across this post, and ...I wonder if I'm in the right way.
Indeed, dealing with cookies ("sessions" in Play's term), would break the rule Restfulness.
Because an api really considered as stateless should be called with ALL the needed data at once (credentials/tokens etc..). The solution I implemented needs both calls: one to authenticate, the other to call the secured API.
I want to make things well, and I wonder some things:
What about the use of Api keys? Should I implement a solution using them instead of this SecureSocial workflow? Api Keys would be sent at EVERY API CALL, in order to keep restfulness.
I think about it since I want my APIs to be reached by some webapps, mobiles and other kind of clients. None of all are forced to manage cookies.
What about OAuth? Should I really need it? Would it replace totally the usage of simple api keys? Always with this objective of several clients, this known protocol would be a great way to manage authentication and authorization.
In one word, should I implement another mechanism in order to be Restful compliant?
this is quite an old Q, but still worth answering as it may interest others.
REST does mandate statelessness, but authorization is a common exception when implementing.
The solution you described requires a single authorization process, followed by numerous service calls based on authorized cookie. This is analog to api keys or OAuth. There's nothing wrong with cookies as long as the service isn't of high-security nature and that you expire then after a reasonable time.
Integrating OAuth into your service sounds a bit of an overkill and is recommended only if you expose the API to 3rd parties (outside your organization).
Related
There is a lot of information on the web about OAuth 2, its different types of flows and where/how to use them. I find that most of these resources discuss authenticating a user for an application, but I am struggling to understand what the best/correct approach would be when consuming third party APIs (i.e. when our own API is the "middleman" between a user and their data in a third party API).
With the help of an example scenario and some diagrams, I would be really grateful for advice/opinions on how I should properly implement integration with third party APIs and what the pros & cons of each approach are.
Starting point
As a starting point, suppose we have a web app, structured as follows:
Frontend - SPA (Angular), hosted with AWS S3 + Cloudfront
Backend - Node, running as stateless AWS lambda functions with AWS API Gateway
Auth0 for handling auth/signin etc. The frontend uses an Implicit OAuth2 flow to obtain access_tokens, which are stored in local storage and included as a header in all requests to the backend.
Potentially also native mobile app(s), consuming the same backend API.
Goal
Now suppose that we wish to add integration with Google Sheets. The new feature would allow users to use their own Google Sheets (i.e. stored in their own Google account) as a data source, with the app having read&write access to the sheet. There may be other integrations in the future, so I am assuming that other APIs would require a similar process.
Problem statement
In addition to the existing OAuth process (which allows users to sign in to the "MyApp" frontend and communicate with the "MyApp API"), there needs to be an additional OAuth process for users to connect MyApp to the third party Google Sheets API.
The documentation has two Quickstart examples, but neither seems to quite fit my needs:
Browser - https://developers.google.com/sheets/api/quickstart/js
Node.js (console app) - https://developers.google.com/sheets/api/quickstart/nodejs
The data from the third-party (Google) API is one of potentially several integration points, so intuitively it seems more logical (and more secure) that all communication with the Google Sheets API should happen in the MyApp API, and not on the frontend/client side. The MyApp API would fetch data, process/manipulate/format it in some way and then present it for display in the frontend or mobile apps.
We require access to each user's own data, so the Client Credentials flow is not suitable. I am focussing on the Implicit or Authorization Grant workflows.
Important note: The trickiness seems to come from the fact that the MyApp API is stateless, so there is no long-lived session in which to store tokens. On that basis, it seems like tokens need to be stored either in the frontend (e.g. local storage/cookies etc) or in a backend database.
Below is my interpretation of two possible approaches. I'd appreciate thoughts/corrections.
Option 1: Implicit flow - tokens stored FE, passed along to BE which then makes requests to Google
Pros:
Allows access to user's own data
Simpler flow, access_token retrieved immediately without needing the code step
Less steps to implement between initial sign-in process and actually obtaining data
No need for a backend database, can resend the token with each request
Cons:
Frontend (browser) has access to Google access_token which seems unnecessary and is a potential security concern
It seems like a strange process to pass the access_token from FE to BE, purely to allow BE to then use that token to make another request
I'm not sure how we would refresh/renew tokens since I understand that storing refresh_tokens on the client is bad practice. It would not be a good user experience if the user had to frequently sign in to reconnect their account
Option 2: Authorization Code Flow - all communication with Google via BE, tokens stored in BE database
Pros:
Allows access to user's own data
Other than the code-request / consent page, all communication with Google is implemented backend, so the tokens are not accessible on the client
Client secret can be used from the BE
Cons:
More complex flow, requires extra steps
Given that the BE is stateless, it's not clear how best to store the tokens. It seems like it would require storing them in a database which is extra complication and seems like it would have security implications - how would you properly secure / encrypt the access_token/refresh_tokens in said database?
Conclusion
Given that the data processing is to happen on the backend, option 2 seems slightly more suitable because the sensitive tokens can be hidden from the frontend app, and several clients (web frontend, mobile apps) have less obligation to be involved in the process with the exception of the initial sign in / user consent. However I’m not sure whether having a database full of user auth tokens is a good idea or how I could properly protect this database.
The good news is that both options are perfectly valid and equally secure. The concern about a short-lived Access Token being in the browser isn't an issue. Equally, if you only held the tokens on the BE, then you would need to implement your own client authentiation/session/JWT blah blah, which presents the same attack surface.
I've done both, and am currently migrating from BE to FE. In my case the reason is that everything I need to do, I can do on the FE, so I end up with no BE at all. This isn't strictly true since I do some onboarding/payment with the BE, but that's about all.
So the best approach depends on factors beyond those in your question, such as the nature of app, what the BE cost is and how important that is, what your devops skillsets look like for maintaining two environments, to what extent a BE is required anyway, vs being completely optional.
My service allow any HTML documents to be converted to PDF using a POST request.
It is mostly used on the backend of my client's server and thus, the API key used for the communication is kept private.
Now, I'm thinking of a way to let my client's visitors be able to call my service on behalf of my client API key, without exposing this secure API Key.
My main issue here is security. If my client add an XHR POST requests that contains the API key, someone can take that API key and use it for their own purpose and abusing my client's account.
I could filter by domain, but this is easily spoofed so it's not possible.
I was wondering if there was a way to call a private service and be identified without risking its identity to be stolen, from the client ('s client) side?
If you're providing this sublet for authenticated users, then it's fairly trivial to give them unique keys (something that hashes their user ID or session against the API key and an initial timestamp, and checks it / logs it / looks for brutes before accessing the API). If you're doing it on the open web, without any kind of user authentication, then rate limiting gets very tricky indeed. Generally you'd want to use a combination of session hashes, IP address, operating system and browser data to create an anonymous profile that gets a temporary key on the frontend. One fairly solid way to do this is to force users through a CAPTCHA before serving a temporary key that allows them a limited number of uses of the permanent key. Any user whose ip/browser/session matches the existing attributes of a known client key is shunted to that one (and gets to skip the CAPTCHA); anyone who doesn't match an existing profile gets the CAPTCHA. That makes you a less attractive target for spoofing. On top of that, you should always rate-limit the entire thing, within a reasonable number of hits per day based on what kind of traffic you expect (or can afford), just so you don't have any surprises. This is the minimal security you'd want if your client's money is on the line every time their API key is used. It will require a simple database to store these "profiles", track usage, check for brutes and maintain the currently valid client keys. Client keys should always be expired regularly - either with a time diff against when they were created, or a regular cron process, or a maximum number of uses, etc.
One other thing I frequently do is rate-limit based on a curve. If I think 5 uses per minute is reasonable, for example, then after 5 uses in a minute from a session, each usage adds a delay of a fraction of a second * the number of uses in the last minute, squared, before the data is served.
The best answer would be to put this all behind a login system and secure that.
Assuming that you are using OAuth kind of system, In that case, make use of Access Token Mechanism that provides access to private API/User's data on behalf of User(Client) without exposing his/her credentials or API Key(Authentication key), also the access token can be expired based on the time/usage.
Example: The access token is generated against a single endpoint that can be the Html Conversion endpoint and will be expired once the action completion.
https://auth0.com/docs/tokens/access-token
And following blog post would be helpful to architect your authentication system
https://templth.wordpress.com/2015/01/05/implementing-authentication-with-tokens-for-restful-applications/
there is no good way to do front-end secure storage but my recommendation is :
is an API that used HMAC signing of requests in combination with OAuth authentication. The API key is actually a signing key. they key does not get transferred. The API key can still get found on the front-end but it becomes useless because you still need the OAuth token to send a valid request.
i know users will have to login in, but you can see this as an advantage because atleast you can log who is using the app by getting information from oauth.
please consider back-end secure storage!
You can use JWT tokens in my opinion. On the basis of username, password or any other info you can generate unique jwt tokens for different users.
Anyone can decipher these jwt tokens but not he unique security token.
If you want to add more more security to tokens, use JWE, encrypted web tokens.
More about these schemes can be found at https://medium.facilelogin.com/jwt-jws-and-jwe-for-not-so-dummies-b63310d201a3
Hashing is a decent option and should be done anyway, but for a fully secure method that wouldn't add too much complexity, you could simply abstract away from the authorization/API key by building your own API to interface with the API. This way you could both limit the kinds of things that can be done with the API key and also completely obscure the API key from the user
I don't think you should always go for user auth or JWT, it just doesn't fit all use cases. The idea of using a Captcha is interesting but also somewhat complex.
If complexity is not an issue I would rather use an infrastructure approach, I'm most familiar with AWS so I'll focus on that. Assuming you can change the host of your front end you can have your site hosted on an S3 bucket, served through a CDN, and create a proxy Lambda function that will hold the logic to call your API and store the API key as an encrypted environment variable. This Lambda you call through an API Gateway that can only be called by a specific IAM role which the S3 bucket also uses. You can also use a Cognito User Pool without authentication.
Going back to a simpler alternative the Captcha approach can be implemented as an attestation provider. I know of two services that do this, Firebase and KOR Connect. Due to Firebase using this approach only for their own resources as of the time of this writing I much rather use KOR Connect as it’s a very simple middleware that basically solves this issue. I won't go into detail about these services as it’s not the main concern of this topic but you can check the documentation their respective links.
I have developed a REST/JSON API. The API exposes a lot of features. The API will be consumed by applications we design internally (mobile apps and web apps), by applications designed by our resellers and by applications designed by businesses. I am looking at securing the application by implementing authentication and authorization. I have 'googled' a lot but my research has left me with more questions than answers.
Our internal application will be used by end users registered on the application. In essence, our application is just a client taking request from the end user, taking it to the REST API and retrieving the data for the end user. Our internal application should be able to perform all the operations exposed by the REST API. What is the best way to handle user login on our internal application? HTTP Basic over SSL or OAuth?
Our reseller applications can create users like they own the users but ultimately the user details get stored in our database. The reseller application will just act as a client taking request from the user and fetching user data. Our resellers applications should only be restricted to some operations of the REST API. What security mechanism will I use to implement this kind of authorization and user login?
I hope my question is clear. Thanks for the help.
From what I understood in reading this there are two parts to your question:
What is the best authentication method for my API?
I recently developed an authentication system for an API that was modelled on OAuth but didn't have every single one of their specifications. The system was basically the same as what Amazon use for their API. [This article]1 is very helpful if you want a secure API authentication model without having to use OAuth.
The model uses these principles:
Authentication data will be passed with every request to the API server
Requests will include a Unix timestamp from when it was generated
The entire request (including the timestamp) will have an HMAC hash generated and sent alongside the rest of the data. The hash is generated using a private key that only the API server and the API client know.
The API takes the data (including the timestamp), generates an HMAC hash using the private key for that user (identified by a user ID, user name, public API key, whatever) and compares it to the hash sent with the request. If this was successful, regular authentication proceeds and the request is processed. Note: the API will check the timestamp and compare it to its own to make sure the request has occured within a valid timeframe of, for example, 30 seconds, 5 minutes, 10 minutes, etc.
Of course, you can use regular HTTP authentication over SSL/HTTPS also, but I find this way to be very good because you achieve a high level of security without needing to implement every aspect of the OAuth protocol.
How you authenticate is up to you essentially. I prefer to go with methods employed by large, trustworthy organisations (such as Amazon). I personally didn't want to go the whole hog with OAuth like Twitter, Facebook etc.
How should I allow different users to access different endpoints in my API?
You should have an internal map in your API server which contains records allowing or denying specific API accounts from accessing certain endpoints. In my API server I decided that all endpoints would be "allow" by default, and I would specify which accounts would not be able to access certain endpoints.
You could also set up different groups or types of API access accounts which could have group permissions like this.
My suggestion would be to [read this article]2 twice, or three times, then read it again. Then, implement the methods suggested within.
Personally, I think the best method for ensuring as much security as possible is to restrict absolutely everything in regards to the request to be within a set of boundaries that you define, e.g. I want this endpoint to only be accessible by GET HTTP requests (all other HTTP methods will throw an error), up to 3 times daily per account, within a 30 second timeframe of request to server, only allow a narrow range of data to be returned, etc.
Limiting the HTTP method is very important to reduce the risk of your API doing things it shouldn't, especially with a RESTful API as endpoints can be used to do multiple things depending on the request method. You can even set your permissions for each API account to restrict certain methods on each endpoint, e.g. API user xxx can GET information from an endpoint but cannot POST, PUT, PATCH etc, or API user xxx2 can POST data but cannot GET any, etc.
[EDIT] 1 and 2: www.thebuzzmedia.com/designing-a-secure-rest-api-without-oauth-authentication/ (not completely removing the link but keeping the url unlinked as it no longer works/redirects to random sites)
We have a large high traffic site with a lot of data on it (similar to Kickstarter), and we want to provide to our content/project creators a means of pulling their data from our site via an API.
Someone suggested I use OAuth, however my experience with OAuth is limited to setting up a twitter datasource.
What I want to do
Provide a user an Application ID and a 'secret'
Allow this user to connect to our application via an api endpoint, authorizing themselves using the api ID and secret
Once verified, allow this user to pull only their data from the application
The data that a user can pull: votes they have cast, pledges they have made, purchases they have made, projects/ideas they have launched, data about those projects/ideas (votes/purchases/orders/cancellations etc)
My question is:
Is OAuth overkill?
Is there a better way to handle a user/users website to connect to our API and pull/verify certain data by using the API we make available, while requiring each incoming request to be authorized for the user/site initiating that request.
Ideally, we will have an endpoint that is accessed as:
https://api.oursite.com/request/params
We want this to be as simple as possible for our users that wish to implement this interface. Thanks for your help!
Generally it's OAuth, in combination with SSL. That's the standard and is likely to stay. Before we saw also logins: username + password to access an API but that's becoming less and less.
So the suggested way is OAuth. There are no serious other solutions yet. To make it easier to adopt your API you could release some classes in some development languages so developers can have a quick start. You could start releasing those classes at for example GitHub to raise adoption of your API and get a quick access to developers. They might, if you do well, even start improving it.
Which are the steps must I follow to implement a token authentication in my web page?
Any summary or links will be appreciated.
I want to implement similar to Facebook or Google, first time client loggin and receive token and then use it in next actions.
I read also about OAuth but I don't want to give access to my application from 3rd party.
Thanks for the long response and it seems clear to me I need to read more about this.
What I want is to know the "steps" to implement a basic web application that uses token authentication. That is user logging once and then can make some actions: add content, edit, etc.
I know what I'm saying is similar to a session, where server adds a SESSION_ID on the HTML header and later request are identified and associated with that session. I read sessions way isn't good to scale so I want to implement a similar system like gmail or facebook before they go to OAuth. Probably I'm talking about something similar to oauth (i don't read in much depth) but witj two-legged instead three-legged.
You should think about your requirements, pick an appropriate protocol and some decent piece of software that implements it.
It's really hard to say more without more details:
are you talking about authentication for one or for multiple web applications? do you need single sign on between different web applications?
should all user data be stored on your server or should user be able to login e.g. with the google account?
should the token contain informations about the user?
on what platform are your applications developed?
what authentication method should be used?
do you want to realize a portal?
There is a really wide range of protocols and tools which might or might not fit to your requirements:
http://en.wikipedia.org/wiki/Category:Authentication_methods
http://en.wikipedia.org/wiki/Category:Identity_management_systems
I personally like CAS ( http://www.jasig.org/cas) for token-base SSO between multiple web applications. It's Java based but also has some support for PHP and .Net.
OpenID is fine, if you want to allow users to login with their Google, Yahoo, whatever account (configurable...) and don't want to store user information by yourself.
Kerberos/SPNEGO is the way to go if you want to haven integrated windows-sso for your corporate intranet applications.
For university applications SAML/Shibboleth probably is best. Outside universities it's somewhat less popular, probably cause it's a fairly complex protocol.
Oh and I almost forget: Most of the web frameworks/standards have there own version of plain-old "form based authentication". Where a user goes to a login form enters its username and password. Both are with or without SSL transported to the web/application server. The server validates it against some kind of database and gives a cookie to the user, which is transmitted and validated every time the user sends a request. But beside all this shiny protocols this seems to be pretty boring :-)
And before doing anything with web authentication, you might think for a moment about web security in general ( http://journal.paul.querna.org/articles/2010/04/11/internet-security-is-a-failure/ http://www.eff.org/files/DefconSSLiverse.pdf) and what you can do to not make it even worse on your site ( http://www.codinghorror.com/blog/2008/08/protecting-your-cookies-httponly.html http://owasptop10.googlecode.com/files/OWASP%20Top%2010%20-%202010.pdf).
see your point.
On the protocol level a very simplistic token approach is HTTP Basic Authentication. But this often doesn't fit, as there is no logout function etc.
A custom, simple cookie based approach can for example look like this:
The server generates some kind of secret (a value that is hard to guess)
When a user tries to access a protected resource, he is redirected to a login form
after successful authentication he gets a cookie. This cookie contains three values: username, timestamp and a hash of {username server-secret timestamp}.
with every user request the server recalculates the hash values and compares it to the value which the client sends in its cookie
(needs more consideration of: httponly and secure flag, transport layer security, replay attacks etc)
Amazon S3 stores its authentication token in an HTTP Header and uses HMAC for calculating it. It's described here: http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?S3_Authentication.html (Not necessarily recommended for using with a browser based web application)
If there is a book about REST anywhere near you, you may look if it has a chapter about authentication. Probably things are much nicer explained there than here :-)
There are some frameworks which are capable of doing this kind of authentication. For security reasons it would make sense to check them first before implementing your own stuff.