Background I have some experience implementing Oauth1a and Oauth2 as a client to connect to 'trusted' 3rd party services (twitter, facebook etc), but first time implementing the resource/authorization servers.
I have a basic but not strong understanding of different grant types, and how Oauth attempts to solve the authorization of a user/resource, while protecting user information (login information etc).
Scenario: we are creating a client-side application (reactJS) which must submit some basic information to a WordPress site. We control (are the authors of and will host) both react and WordPress on the same server.
We are using WP Rest API:
http://v2.wp-api.org/
And Oauth server plugin for wordpress
https://en-ca.wordpress.org/plugins/oauth2-provider/
Question
The further we get into implementation, the more I ask, what security to I gain at all by adding Oauth in this scenario?
For development and testing, the permissions callback on the POST to our REST endpoint is TRUE (open to any request), and now we are trying to secure it so only our application can submit information to WordPress.
The author of the Oauth server for WordpPress describes for this:
The access token used to preform a CRUD WP REST API action MUST has been acquired via the password grant type (user credentials).
Which requires embedding the following in the client:
client ID
client secret
wordpress user ID
wordpress user password
since:
The access token MUST be assigned to a user id with the correct
WordPress capabilities to preform the CRUD action.
Just to get back an access token.
Note: users do not log in via our react application. The application itself acts as one user in this case.
I must be missing something, exposing the WordPress user name and password seems less secure than skipping Oauth completely, leaving the POST endpoint open, and implementing some kind of submission abuse check, via submission rate, IP or other.
With Oauth2: Someone in control of the client can watch the XHR request and retrieve all information necessary to submit malicious data.
Without Oauth2: someone could use one of many discovery techniques to find our public endpoint and try to submit malicious data.
Things which I may be missing: should I be encrypting/hashing the password, secret, ID etc before embedding in the client?
Should I be separating out our authorization server from the resource server?
Have I missed the point, and Oauth is not a good candidate for this scenario?
Any insight or clarification greatly appreciated.
Related
What is the difference between using Google OAuth and signing in users at the frontend of the application, and signing in users at the backend side of the application?
Example: Signing in users and getting the ID and a auth object in React or letting Node/Express handle everything, the prosess, redirecting and store it in a database.
Is there any advantages for one or the other methods, which are most common and are there any "rules"?
What is the difference between using Google OAuth and signing in users
at the frontend of the application, and signing in users at the
backend side of the application?
So to clarify to everyone reading this, signing in users at the backend side of the application is another way of saying OAuth for servers and signing in users at the frontend of the application is OAuth for JavaScript browser applications such as React.
Signing in users via OAuth for servers and browsers results in a 'token' that a server/browser can use to make requests on behalf of the user. We are asking the user to provide us access to their information via an outside service provider such as an email address, identification of some sort and it will be inside that token as well as some possible permissions that allow us to take actions on behalf of that user.
Is there any advantages for one or the other methods, which are most
common and are there any "rules"?
Server-side OAuth is usually used when we have an app that needs to access user data when they are not logged in. So if you are attempting to build an application that needs to access the users email every ten minutes and possibly delete emails on the users' behalf, you would want to be able to access their email account every 10 minutes regardless of whether they are logged into our application. So for this use case we want to make use of Oauth for server.
Otherwise, if we are not trying to do anything on behalf of the user except sign them into our app, then we can just go with OAuth for browser.
Those two things are very different. Without knowing the specifics of what you're trying to accomplish, you should know as a general rule that front-end-only authentication and authorization leaves you extremely vulnerable.
If someone knows JavaScript well, or is using editing plugins, or any of a million different things, they can bypass much front-end authorization. Or they could just watch to see what calls your app makes to the back end, then simulate those calls from something like Postman, bypassing your web front end entirely.
If you're not securing your backend, you're not secure. Typically systems do both.
It is just a different ways of registering users to our website.
Signing in users at the frontend using OAuth can be very handy as it enables our users to not go through our boring forms in our website. Using OAuth is just one click away from registering users in our website. Beneficial to both the clients and developer.We are provided with the general information about clients by the provider(google,facebook) just clicking on one button.
Signing in users at the backend side is the traditional way of registering our clients. Here we force our client to fill the forms in our website(which may be painfull if it is a long form) and all the filled data is stored in our database.
So they are both different ways to register clients to our websites. Both are used very often. It depends on usecase and needs. Oauth can be used if you want to attract more clients by registering them just by one click.
I need to authenticate users in browser (not mobile app) using AWS Cognito with username/pass, not FB/google IdProviders.
There are a lot of docs but they seem to be separate blocks which either incomplete, do not fit the requirements or do not fit each others :(
I created Cognito User Pool, then Identity pool and tied the userPool to the idPool, then I stuck. Do not know which library to use and how to use it.
The closest I find are:
https://aws.amazon.com/sdk-for-browser/ but my experience is not enough to convert their FB samples to not-using FB
https://github.com/aws/aws-amplify but using this lib I'll have to study React/Angular from the very beginning (I'm not a front-end developer, sorry) and I have no clue how to convert their npm-based samples to front-end javascript (npm is for NodeJS thus back-end, isn't it?).
All I need is plain html form with username/pass, send the request to Cognito and a way to check during the next page load whether the password was correct. If it matters I will use AWS Lambda as back-end for processing future tasks.
How can I do it? Is there a tutorial/doc for my case?
Thank you.
You can use AWS Cognito UserPools Hosted UI for your use case. The simplest form of authentication is using the Implicit Grant.
For more information about setting up Hosted UI refer Add an App to Enable the Hosted Web UI.. This will create a UserPool where users can register them self (If you plan to restrict this, you will need to either add users using the AWS Web Console, Cognito UserPools or using their SDK)
The steps are as follows.
Set up Cognito Hosted UI and register your application domain. This will create the login/registration pages for you where each of this will have a unique URL. What you have to do is, if the user is not authenticated (Let's discuss how to detect it later), you need to redirect the user to the Login page.
In the Login URL, you also need to specify the redirect back URL to the application so that after a successful login, Cognito will redirect back the user to the application providing the token in a query string.
You can then access the id_token from inside the application and use it for querying the backend.
Since the id_token is a JWT token you can verify it at your Backend using the public key available at the Cognito token endpoint.
To implement the JWT verification, you can also refer Cognito JWT Token validator NodeJS module.
Note: If you need to keep the user's logged in for a longer time period (Than 1 hr), you might need to use the Code Grant flow which will return a Refresh Token, which could be used to retrieve new id_tokens programmatically.
Quick short background
I'm building a standalone web app using Angular JS 1.5. This web app makes usage of a API built with Laravel 5.2 (no sessions, just JWT Tokens and REST calls). Using Laravel-Socialite, I managed to make the following structure. It works nice and all, but we kind of have a overload of redirects.
The Button calls a /facebook route that invokes the Socialite magic box which leads to redirect to the Facebook Page for authorization.
After I achieved this, I noticed that a Facebook Login LOOKS a lot more of a front-end task than a back-end one. It's just about helping the user quickly sign up using Facebok available data or sign in without a password.
The Problem
Socialite makes usage of my Facebook App Secret, not to mention that it's a known environment server operation, while a Front-end we may never trust. Here is what I managed to achieve using JavaScript SDK (with AngularJS).
On a first-time access, I can get that information and sign up the user and automatically sign him in. But the problem lies on a existing user.
In this case, technically I can use the response.email information that Facebook gave me and make a request to my API to make a login without a password. But can I really do it? How do I make sure the request is being made because Facebook authorized it? After Facebook replies to my Web App, what is a secure way to tell my server that it can issue a JWT Token to that email?
Conclusion
Do I make the three-step redirection (Web App → Server API → Facebook) to sign in / authenticate a user using Facebook or is there something I'm missing here that could be the key to transferring this responsibility to the front-end (and avoiding a 3-step-redirection)?
I'm building client server REST application.
Client side is based on Angular while server is PHP (not that it matters much anyhow).
What I am wondering if there are any best practices, good examples of captcha implementation in this case? Captcha would be used for user registration etc.
I'm not limited to any specific libraries, only requirement is that there cannot be any calls to 3rd party servers on client side (js libraries hosted on 3rd party servers or req api key etc).
thanks
When google captcha approves one user, it provides you a token.
So imagine this scenario. A User is about to save, and uses the captcha, the captcha does its business and gives you a token, it is all that matters.
If you want to see a "tentative" flow of requests for this.
The User should pass the captcha before registering and retrieve the token that it provides in the front end.
User clicks save, you receive the captcha token in the backend as form data. You validate the token with Google via an API. If Google verifies the token as valid, you can save the user or reject if Google returns an error.
The frontend listens for success or error and what kind of error. IF error is captcha, force a retry, get a new token.
Backend receives a new token in form data and repeats step 2.
You can have a look on google-recaptcha. Its angular implementation is here
vcRecaptcha
Google's new-ish reCaptcha is pretty slick. They have several easy to understand examples and usage scenarios.
https://www.google.com/recaptcha/intro/index.html
Edit: To address your specific question of how to implement this in a RESTful application, I'd make two files. One would be a public-facing file like index.php and the other would be a back-end file that would hold the private information.
I could copy/paste my previously-written how-to here, or I could just link you to the article I wrote 2 months ago.
02/20/2011:
It was confirmed by Facebook today that indeed there is one call in which the access_token is broadcast in the open . . . it just happens to be one call I use to make sure that the USER is still logged in before saving to my application database. Their recommendation was to use the SSL option provided as of last month for canvase and facebook as a whole. For the most part the Auth and Auth are secure.
Findings:
Subsequent to my posting there was a remark made that this was not really a question but I thought I did indeed postulate one. So that there is no ambiquity here is the question with a lead in:
Since there is no data sent from Facebook during the Canvas Load process that is not at some point divulged, including the access_token, session and other data that could uniquely identify a user, does any one see any other way other than adding one more layer, i.e., a password, sent over the wire via HTTPS along with the access_toekn, that will insure unique untampered with security by the user?
Using Wireshark I captured the local broadcast while loading my Canvas Application page. I was hugely surprised to see the access_token broadcast in the open, viewable for any one to see. This access_token is appended to any https call to the Facebook OpenGraph API.
Using facebook as a single click log on has now raised huge concerns for me. It is stored in a session object in memory and the cookie is cleared upon app termination and after reviewing the FB.Init calls I saw a lot of HTTPS calls so I assumed the access_token was always encrypted.
But last night I saw in the status bar a call from what was simply an http call that included the App ID so I felt I should sniff the Application Canvas load sequence.
Today I did sniff the broadcast and in the attached image you can see that there are http calls with the access_token being broadcast in the open and clear for anyone to gain access to.
Am I missing something, is what I am seeing and my interpretation really correct. If any one can sniff and get the access_token they can theorically make calls to the Graph API via https, even though the call back would still need to be the site established in Facebook's application set up.
But what is truly a security threat is anyone using the access_token for access to their own site. I do not see the value of a single sign on via Facebook if the only thing that was established as secure was the access_token - becuase for what I can see it clearly is not secure. Access tokens that never have an expire date do not change. Access_tokens are different for every user, to access to another site could be held tight to just a single user, but compromising even a single user's data is unacceptable.
http://www.creatingstory.com/images/InTheOpen.png
Went back and did more research on this:
FINDINGS:
Went back an re ran the canvas application to verify that it was not any of my code that was not broadcasting.
In this call: HTTP GET /connect.php/en_US/js/CacheData HTTP/1.1
The USER ID is clearly visible in the cookie. So USER_ID's are fully visible, but they are already. Anyone can go to pretty much any ones page and hover over the image and see the USER ID. So no big threat. APP_ID are also easily obtainable - but . . .
http://www.creatingstory.com/images/InTheOpen2.png
The above file clearly shows the FULL ACCESS TOKEN clearly in the OPEN via a Facebook initiated call.
Am I wrong. TELL ME I AM WRONG because I want to be wrong about this.
I have since reset my app secret so I am showing the real sniff of the Canvas Page being loaded.
Additional data 02/20/2011:
#ifaour - I appreciate the time you took to compile your response.
I am pretty familiar with the OAuth process and have a pretty solid understanding of the signed_request unpacking and utilization of the access_token. I perform a substantial amount of my processing on the server and my Facebook server side flows are all complete and function without any flaw that I know of. The application secret is secure and never passed to the front end application and is also changed regularly. I am being as fanatical about security as I can be, knowing there is so much I don’t know that could come back and bite me.
Two huge access_token issues:
The issues concern the possible utilization of the access_token from the USER AGENT (browser). During the FB.INIT() process of the Facebook JavaScript SDK, a cookie is created as well as an object in memory called a session object. This object, along with the cookie contain the access_token, session, a secret, and uid and status of the connection. The session object is structured such that is supports both the new OAuth and the legacy flows. With OAuth, the access_token and status are pretty much al that is used in the session object.
The first issue is that the access_token is used to make HTTPS calls to the GRAPH API. If you had the access_token, you could do this from any browser:
https://graph.facebook.com/220439?access_token=...
and it will return a ton of information about the user. So any one with the access token can gain access to a Facebook account. You can also make additional calls to any info the user has granted access to the application tied to the access_token. At first I thought that a call into the GRAPH had to have a Callback to the URL established in the App Setup, but I tested it as mentioned below and it will return info back right into the browser. Adding that callback feature would be a good idea I think, tightens things up a bit.
The second issue is utilization of some unique private secured data that identifies the user to the third party data base, i.e., like in my case, I would use a single sign on to populate user information into my database using this unique secured data item (i.e., access_token which contains the APP ID, the USER ID, and a hashed with secret sequence). None of this is a problem on the server side. You get a signed_request, you unpack it with secret, make HTTPS calls, get HTTPS responses back. When a user has information entered via the USER AGENT(browser) that must be stored via a POST, this unique secured data element would be sent via HTTPS such that they are validated prior to data base insertion.
However, If there is NO secured piece of unique data that is supplied via the single sign on process, then there is no way to guarantee unauthorized access. The access_token is the one piece of data that is utilized by Facebook to make the HTTPS calls into the GRAPH API. it is considered unique in regards to BOTH the USER and the APPLICATION and is initially secure via the signed_request packaging. If however, it is subsequently transmitted in the clear and if I can sniff the wire and obtain the access_token, then I can pretend to be the application and gain the information they have authorized the application to see. I tried the above example from a Safari and IE browser and it returned all of my information to me in the browser.
In conclusion, the access_token is part of the signed_request and that is how the application initially obtains it. After OAuth authentication and authorization, i.e., the USER has logged into Facebook and then runs your app, the access_token is stored as mentioned above and I have sniffed it such that I see it stored in a Cookie that is transmitted over the wire, resulting in there being NO UNIQUE SECURED IDENTIFIABLE piece of information that can be used to support interaction with the database, or in other words, unless there were one more piece of secure data sent along with the access_token to my database, i.e., a password, I would not be able to discern if it is a legitimate call. Luckily I utilized secure AJAX via POST and the call has to come from the same domain, but I am sure there is a way to hijack that.
I am totally open to any ideas on this topic on how to uniquely identify my USERS other than adding another layer (password) via this single sign on process or if someone would just share with me that I read and analyzed my data incorrectly and that the access_token is always secure over the wire.
Mahalo nui loa in advance.
I am not terribly familiar with Facebook's authentication/authorization methods, but I do believe that they implement oauth (or something close to it) for delegation, distributed authorization, and "single sign-on".
OAuth is described by RFC-5849
EDIT: Facebook Uses OAuth 2.0 which is still in working draft.
In OAuth, and similar systems, the "access_token" is only part of the picture. There is also typically a secret key, which is known only by the service provider (facebook) and the client application (your app). The secret key is the only part that is expected to stay secret - and that part is never sent over the wire (after it's initial issuance).
In the case of Facebook, I think the secret key is assigned to you when you register your application to use their API, and the 'access_token' is returned to you for a given user, whenever the user agrees to allow your app to access their info.
Messages are sent in the clear, including the user's username, and the relevant "access_token"; However, each message must also include a valid signature in order to be accepted by the server. The signature is a cryptographically computed string, that is created using a technique called HMAC.
Computing the HMAC signature requires both the token and the secret, and includes other key parts of the message as well. Each signature is unique for the given message contents; and each message uses a nonce to ensure that no two messages can ever be exactly identical.
When the server receives a signed message, it starts by extracting the access_token (clear-text), and determining which app the token was issued for. It then retrieves the matching secret from its own local database (the secret is not contained in the message). Finally, the server uses the clear-text message, the clear-text access_token, and the secret to compute the expected HMAC signature for the message. If the computed signature matches the signature on the received message, then the message must have been sent by someone who knows the same secret (i.e. your application).
Have a look at Section 3.1 of RFC-5849 for an OAuth specific example, and further elaboration on the details.
Incidentally, the same approach is used by Amazon to control access to S3 and EC2, as well as most other service providers that offer API access with long-term authorization. Suffice it to say - this approach is secure. It might be a little counter-intuitive at first, but it makes sense once you think it through.
Adding a few links and quotes from Facebook Documentation:
Facebook is indeed using the HMAC-SHA256 algorithm. Registration document (PHP Example reading signed_request section).
Always verify the signed_request:
If you are unable to validate the
signed_request because you can't embed
your application secret (e.g. in
javascript or a desktop application)
then you MUST only use one piece of
information from the payload, the
oauth_token.
The Authentication Document contains a lot of useful info about the different flows you may use to authenticate a user. Also read the Security Considerations section at the bottom of the page:
Cross site request forgery is an
attack in which an trusted
(authenticated and authorized) user
unknowingly performs an action on
website. To prevent this attack, you
should pass an identifier in the state
parameter, and then validate the state
parameter matches on the response. We
strongly recommend that any app
implementing Facebook user login
implement CSRF protection using this
mechanism.
It was confirmed by Facebook that indeed there is one call in which the access_token is broadcast in the open - it just happens to be one call I use to make sure that the user is still logged in before saving to my application database. Their recommendation was to use the SSL option provided as of last month for canvas and Facebook as a whole. For the most part the Auth and Auth are secure.
To ensure a secure interface between a third party application and a Facebook application or even any website that uses Facebook Single Sign on, an identity question would provide the extra layer when used in conjunction with the access_token.
Either that or require your users to use Facebook with the new SSL feature of Facebook and Facebook Canvas Applications. If the access_token is broadcast in the open it cannot be used to uniquely identify anyone in your third party database when needing to have a confirmed identity before database interactions.