CouchApps and user authentication - couchdb

I posted a variation of this question to the CouchDB user list and haven't received a response yet.
I'm curious to know if anyone else has built a so-called "CouchApp"; a pure HTML/JavaScript application hosted directly within CouchDB. If so, how did you handle user authentication? I'd like to be able to create a typical login form (username, password) and then use those credentials either against a view or some other mechanism before passing the user along to the application (while storing their (encrypted) user ID in a cookie, presumably).
I'm used to simply proxying through something like couchdb-python and a normal web server, but would like to know any best practices with respect to authenticating users in these kinds of CouchApps.
Edit: A year later, and this is now built into CouchDB. This video is a great demonstration. (Thanks Daniel!)

CouchDB has released a simple authentication api but has no in built authentication mechanisms as of yet. The simplest and easiest way to do this is to use an http proxy for authentication. However this has limitations on how much you can restrict access on a per document basis. When CouchDB gets some more support for built-in authentication modules then it should be easier.
If you want to try your hand at coding an authentication module then you can check out the source for the javascript security_validation tests in this file:
http://svn.apache.org/repos/asf/couchdb/trunk/share/www/script/couch_tests.js
and the default_authentication_handler in this file here:
http://svn.apache.org/repos/asf/couchdb/trunk/src/couchdb/couch_httpd.erl
that would get you started anyway.

This question has been around for a while (1.5 years!) and things have matured quite a bit since it was answered. Watch the video above, but it doesn't explain how to build it into your app. It looks like most of the answers are now found here: Security Features Overview and at the end of this document: CouchDB Security.

Related

How to secure server API in order to reject fake-client calls?

I'm developing both server and client side of a web application and it is almost finish. Now, it is time to secure it.
I read lots of articles and Q-A sites to understand the principles of the concept. But there are still question marks on my mind.
There is a similar question here:
How do I secure REST API calls?
They suggested to use token-based security system, which is very common and practical way. Also services like Firebase, Auth0 are providing this security system.
And this is about "how and where to store token": https://auth0.com/docs/security/store-tokens
If so, how can token protect server from fake-calls while we are storing it in the browsers local storage?
Explaining it with an example in order to be clear:
My client-side code has a form with options. One of the option can be selected via drop down option and there are only "1,2,3,4" in those options. So that, client can never send a form with "5" value to the server. But what if someone use a API tool (for example postman) to send a form with a value of 5? Attacker still can add a token to that request. First login to system as normal user. Than open the developer console of the browser, copy your token and paste to the header of your fake-request.
Not allowing the cross origin calls may solve the problem. But I am not sure if this means server and client should run on the same domain (or host)?
Bonus from stackoverflow: Stackoverflow's use of localstorage for Authorization seems unsafe. Is this correct else how do we strengthen it?
They are also discussing the similar question from another aspect. (Not for the server security but for the user's security.)
Not related but in case of need: front-end is developed with Angular 5, server is developed with Java and Spring Framework.

Authentication middleware in Express NodeJS - Best practice

I'm writing my first Express NodeJS app and I want to know what is the best practice when it comes to authentication middlewares?
I'm using access tokens and cookies (which are composed from user id and some random bytes) for each new user, and for some routes I want only given users to have access to it.
Is a good idea to access database from a middleware? Or where should I check if a given user has access to a given resource?
Thank you!
There are many modules built for authentication purpose for nodejs applications. However, the most commonly used module for nodejs/expressjs is Passport. If you wish to stay isolated from such libraries, nodejs has built-in libraries for encryption etc, for example, check this out.
For sessions and cookies, using signed cookies is always a good practice. Check out this SO post. There are many good practices for maintaining security (say, using https over http, token based authentication, etc.) followed throughout the development grounds, which you'll learn as you go on. Here is a short tutorial of JWT(JSON Web Tokens) for a good introduction to token based authentication in JSON you can check out.
Happy coding :)

JSON Web Token Auth Service - checking status on separate server to protect routes. NodeJS

For a project I’m working on currently I am developing an API using Node/Express/Mongo and separately developing a website using the same tools. Ideally I want to host these on separate servers so they can be scaled as required.
For authentication I am using jsonwebtoken which I’ve set up and I’m generally pleased with how it’s working.
BUT…
On the website I want to be able to restrict (using Express) certain routes to authenticated users and I’m struggling a little with the best way to implement this. The token is currently being saved in LocalStorage.
I think I could pass the token through a get parameter to any routes I want to protect and then check this token on the website server (obviously this means including the jwt secret here too but I don’t see a huge problem with that).
So my questions are
Would this work?
Would it mean (no pun intended) I end up with ugly URLs
Would I just be better hosting both on the same server as I could then save the generated token on the server side?
Is there a better solution?
I should say I don’t want to use Angular - I’m aware this would solve some of my problems but it would create more for me!
First off, I'll answer your questions directly:
Will this work? Yes, it will work. But there are many downsides (see below for more discussion).
Not necessarily. I don't really consider ugly urls to include the querystring. But regardless, all authentication information (tokens, etc.) should be included in the HTTP Authorization HEADER itself -- and never in the URL (or querystring).
This doesn't matter so much in your case, because as long as your JWT-generating code has the same secret key that your web server does, you can verify the token's authenticity.
Yes! Read below.
So, now that we got those questions out of the way, let me explain why the approach you're taking isn't the best idea currently (you're not too far off from a good solution though!):
Firstly, storing any authentication tokens in Local Storage is a bad idea currently, because of XSS (Cross Site Scripting attacks). Local Storage doesn't offer any form of domain limitation, so your users can be tricked into giving their tokens up quite easily.
Here's a good article which explains more about why this is a bad idea in easy-to-understand form: http://michael-coates.blogspot.com/2010/07/html5-local-storage-and-xss.html
What you should be doing instead: storing your JWT in a client-side cookie that is signed and encrypted. In the Node world, there's an excellent mozilla session library which handles this for you automatically: https://github.com/mozilla/node-client-sessions
Next up, you never want to pass authentication tokens (JWTs) via querystrings. There are several reasons why:
Most web servers will log all URL requests (including querystrings), meaning that if anyone gets a hold of these logs they can authenticate as your users.
Users see this information in the querystring, and it looks ugly.
Instead, you should be using the HTTP Authorization header (it's a standard), to supply your credentials to the server. This has numerous benefits:
This information is not typically logged by web servers (no messy audit trail).
This information can be parsed by lots of standard libraries.
This information is not seen by end-users casually browsing a site, and doesn't affect your URL patterns.
Assuming you're using OAuth 2 bearer tokens, you might craft your HTTP Authorization header as follows (assuming you're representing it as a JSON blob):
{"Authorization": "Bearer myaccesstokenhere"}
Now, lastly, if you're looking for a good implementation of the above practices, I actually wrote and maintain one of the more popular auth libraries in Node: stormpath-express.
It handles all of the use cases above in a clean, well audited way, and also provides some convenient middlewares for handling authentication automatically.
Here's a link to the middleware implementations (you might find these concepts useful): https://github.com/stormpath/stormpath-express/blob/master/lib/authentication.js
The apiAuthenticationRequired middleware, itself, is pretty nice, as it will reject a user's request if they're not authenticating properly via API authentication (either HTTP Basic Auth or OAuth2 with Bearer tokens + JWTs).
Hopefully this helps!

Authorisation strategy for a first-party express based node API

I'm tackling the design of my first API and am struggling somewhat with authorisation concepts - I was hoping some kind people could give me some advice!
What I'm building:
An API that will eventually be accessed by third party apps and a mobile app.
A web-based 'client' (first-party single page app) that will use the API. (Should this first-party app be 'a part' of the API, or a completely separate node app?)
Technology I plan to use:
Node
Express
Passport
Mongodb with Mongoose
I'm not wed to express or passport, they just seem like the best options and are well documented - bit I wouldn't want a potential solution to be dismissed because of alternative dependencies. Same with Mongoose, I actually prefer the look of Monk (or even just Mongojs), but every tut seems to use mongoose, so seems like the safest option for a node beginner.
Authenticating a user is simple enough (I've gone through the fantastic Beer Locker tutorial), what I'm struggling with is ongoing authorisation. Naturally I don't want the user to have to input a username and password with every request they make - should this information be stored locally and sent with every request? (if so, how? I can't find any info on handling an API with a session) or should I be working with tokens of some sort? The small amount of reading I did on 'Digest' authorisation (including the Beer Locker tutorial follow-up) made it seem like it had security issues, at least with the Passport implementation (this I don't fully understand, but seems to relate to hashing passwords, which passport doesn't do as standard, and only MD5 is supported even if it's added?).
I have built a working API that I can authorise with 'Basic' (directly, through Postman), so I have the foundations in place - authorisation works, I just need the tools to take that to the next step and add sessions into the mix!
I've been trying to get my head around this for a couple of days now, but I fear I'm too stuck in a more traditional local web-app workflow - the whole API thing is throwing me somewhat.
Any help is hugely appreciated, even if it's just pointing me at an appropriate tutorial - the above set of requirements must be quite common!
I have come accross this problem too...
I can only recommend doing this for the beginning:
http://scotch.io/tutorials/javascript/easy-node-authentication-setup-and-local
tell me if it helped :)
As I understand you have done the authentication and the only thing you have to do now is store somewhere that the current user is authenticated, his name, roles etc to use later with other requests. In the Passport you will do it in the function callback (instead of the "If this function gets called..." comment).
Now you have to decide, you have two options:
Store the user information (name, roles etc.) on your server (in a session) and give the user some long code which will identify his session for the next requests
to store the information on your server you may use for example the express-session middleware
it would be probably best to save the session identifier in a cookie, but read some security issues before
Give the user something that would prove to you he/she is authenticated and which name, roles etc. he/she has
you can generate a token, that contains the user information (name, roles etc.) that the user will send with every request. to know this token is legit, you will have to sign it. more on this is on jwt.io and you can use express-jwt middleware.
you dont have to care about storage of session with this one
the token can be placed to a cookie too, but same security issues apply. it is still considered better that localstorage (more here)

Commonly used solutions for credential caching?

I have question about credential caching in applications. I've searched around on the net for solutions to this problem, but I haven't found anything (which is really surprising, since this is something that every Facebook, Twitter, and email client application has to deal with).
My question is this:
Let's say I'm building some simple Twitter client. I don't want to force the user to enter their password every time. How do most applications tackle this problem? At some point, the client needs to make an API call to authenticate (which includes the password, which is usually in plain text). However, saving the password in plain text somewhere not the correct solution, obviously. So, how do most apps do this safely? I suppose you could cache the password in a file or db if the password is encrypted, but then how do you safely store the decryption key? Or is it generated at runtime using unique information from the client machine as a seed?
Are there any resources (articles, books, etc.) that talk about this? How do most apps handle this?
Thanks!
Single-sign-on (SSO) setups accomplish what you describe typically by providing centralized methods to generate, distribute and validate a key using some type of session ID.
See for one method (used by StackExchange/StackOverflow):
http://openid.org/
Here's something I didn't know: This category of functionality is known as Federated Identity. For instance, our web system where I work offers (but doesn't require) Shibboleth. See here for a list of options:
http://en.wikipedia.org/wiki/Category:Federated_identity

Resources