I have a standard HTML login page, which I would much rather use than the standard HTTP authentication pop-up provided by browsers. Today, I am using session cookies to keep track of the session after logging in, but I'd like to be stateless and pass the HTTP authentication every time. The web services I am hitting already support this, so this is a browser-only issue.
Adding authentication credentials is trivial in jQuery, but I don't know how to keep them around. If you go from the login page (a jsp) to the Home page (another jsp) you clearly don't keep the username and password fields from the login page. I know some browsers will store your HTTP authentication credentials if you enter them from the pop-up, but I don't know if they get stored when using an XHRRequest. If they do, is there much consistency among browsers?
Also, the user needs to be able to "sign out" of the application, too. If the browser stores the authentication credentials, is there a way to clear them using JavaScript.
I feel like I can't be the first person to try to solve this. Is there some jQuery plugin or something that already handles this? Or is it simply not possible to do what I'm trying to do?
You have 2 options:
1) Client-side storage of credentials -- not a good idea. For obvious reasons you don't want to store the username/password on the client. If you had a hashed version of the password, it might not be so bad, but still not recommended. In any case, if you're going to store on the client side, you either have to use a cookie, or HTML5 local storage (which is not widely supported, yet)
2) Server-side storage of credentials -- typically done with sessions. Then the resultant Session ID can be passed back to the client and persisted in either a cookie or in the URL of each subsequent AJAX call (?SESSID=xyz for example)
The server-side approach would be the most secure, reliable, and easiest to implement
Okay, I'll take a stab at helping ...
Firstly, understand how HTTP authentication works. There are two versions - Basic and Digest. Basic transmits in plaintext, digest is encrypted. With these types of authentication, the username/password are passed in the HTTP header with every single request. The browser captures these at login and they are stored in an inaccessible browser session cookie which is deleted when the browser session is closed. So, in answer to one of your questions, you can't access these from javascript.
You could create your own session cookie variables for username and password. The jQuery functions for this are really simple. See jquery-cookie module as one example of how to set session cookies. These could be retrieved from the session cookie and sent with each ajax request and validated in the server. However, this is not a particulary good way to do authentication since sniffing the network will allow anybody to easily grab your auth details. But, it would work.
Using session cookie based authentication where the session ID is sent sent with each request is the best way to do this. At the server side, you need to have a function called for every HTTP request. This function should do the following:
check to see if the session has been authenticated
if no:
redirect to login screen
if yes:
do authorization and allow the user access to the page
Most web frameworks support session cookie authentication and the management of session ids at the server. This is definately the way to go.
This is interesting one.
Manage user sessions on server by use of cookies. Create a session when user first accesses the login page and pass the session id/key as value to one of the cookie via response. When the user is authenticated put user "key" info in cookie and "values" in application context at server. Once user is logged, any subsequent request will be authenticated based on session cookie value at server. Authorization will be done based on user "key" passed as cookie value.
On logout clear the session based cookies from server and refresh the site to default page.
Cookies are bizarre with different browsers - just a note ;)
Hope this helps.
Update
The answer below was posted in 2012 and the links are mostly dead. However, since then, a more elegant standards-based approach to the same solution appeared using JSON Web Tokens. Here is a good blog post explaining how to use them.
Most answers miss the point, which is to avoid having any server-side session. I don't want any application state in the server. I'll award the bounty to answer that came closest, but the real credit goes to the rest-discuss group and Jon Moore for the correct answer and to Mike Amundsen for helping me to actually understand it.
The best answer I've gotten is to use a cookie, but not the typical automatic session id cookie given to you by most application servers. The cookie (which will automatically be sent with each subsequent request) is a user identifier and time signed by the server. You can include an expiration time with the cookie so it simulates the typical 30 minute session on a server (which means you have to push it forward with subsequent requests) as well as keeps the same cookie from being valid forever.
The XHR/AJAX part is a red herring. This will work whether you are doing XHR requests or an old-fashioned page-by-page web application. The main points are:
The cookie is automatically sent on subsequent requests so there's no
special scripting required - it's just how browsers work already.
The server does not need to store any session for the user, so the user
can hit any server in a cluster and not have to re-authenticate.
Slightly interesting in that you consider pushing some of the authent to the client. If you want a conventional solution, KOGI's server-side suggestion is the way to go.
But you also seem to be asking questions about memory leaks involving your user supplied secrets. Good questions. But to take a general stab at answering that I'd say it would have to be browser specific. It's browser internals, javascript engine internals -dependent where a client side application (i.e., the browser, or js in the browser) is storing the values the user inputs.
Most likely those values are not replicated needlessly throughout memory, but there's no way to guarantee that. Apart from responsible javascript coding practices, there's nothing you can do to guarantee the limit of locations of user inputs.
Slight digression
The basic point is if you store it on the client it is not really secure -- unless, the serve stores encrypted information on the client with a key that only the server (or the user via their correct credentials), has. So you could conceivably code a JS application to do some authent on the client -- much the same as how bank card (used to?) do POS authent by checking the PIN to the PIN on the card, and not back at the DB. It's based on the (somewhat flimsy) assumption the user has no direct read/write access of the "dark area" cookie/local storage on client / mag strip on bank card. So I would only advise this as disqualifier for false authents and not as a sole qualifier for the credentials.
Main point
If you do want to be stateless, just store user credentials in localstorage, or as a cookie but encrypt them with a server key. When you need them send an XHR with the encrypted / use stored credentials to the server over HTTPS, let your server decrypt them and send them to the callback. Then pass those cleartext of HTTPS to do your authent.
Related
I am new to web application , I am learning cookies and session, I understand HTTP is stateless protocol to make it stateful we use cookies at client side and session at server side.
When user requests a webpage it sends all the cookies available for that
browser on the PC.
If any one of the cookie matches with server side database , the server
shows the data , else sends set cookie with a session iD(optional to send
create session and send the session ID).
a. If server sends set cookie the client sends cookie in all respective
requests with the session id , only if the domain name matches with the
server to which the client sent .
Now my doubt is suppose I am working on an e-commerce site. And the server sends the number of items added to the cart till the user is not logging out , now it can be done using cookie alone why do we need session at all?
Is there something I am not understanding ?
These are separate concepts:
Cookie - Browser sends this with every request automatically
Header - Part of a HTTP request, the browser will only send data here if instructed.
Access token - Contains secret which may be a JWT (and identify the user) or a random set of characters
Session - a token bound to a user + device that authenticates the user. If the user doesn't have an access token, they can use the session to get a new token.
You can see that Cookie/Header are the where and access token/session token are the what.
The user needs to authenticate in your service. That means you need to be able to identify the user. That may be done with a JWT, session token, IP address, a signature, etc... And that is separate from how this data is transmitted to the service from the user.
So when you say why do you I need session when the user has cookies, these are totally unrelated. The session id may be saved in a cookie, that's just one option.
Whether or not the session id in a cookie corresponds to actual data on the server side is another completely separate question. Should the session token be a encrypted (or signed) object, like a JWT which contains user identifying information, or should that data be saved in a server side DB, and only transmit a random-string identifier. Who knows?
The answer is going to be based on what's critical for your application. Generally speaking, session tracking on the server side is a legacy concept, and the new hotness (which is old now), is to make the sessionId a JWT saved a HTTP Only cookie for security. And then passed on every request.
Lot's of services have sessions and access token management baked in, and for a working example and more about tokens, check out any one of many knowledge bases.
Because:
There may be, and probably is, sensitive data in that session, e.g. the user's id, identifying who the user is. If you just stored the user's id in a cookie, the user could manipulate it and easily pose as anyone else. There are of course ways to mitigate that, but simply not allowing the user to futz with the cookie contents (because it's just a meaningless session id) is the simplest.
It allows the server to manage session state; e.g. if a user suspects somebody is logged in as them on another device, they can invalidate all other sessions ("log me out everywhere" functionality).
You may be storing a lot of data, and sending it back and forth in a cookie on every request can become rather wasteful.
You may want to associate something like a shopping basket with the user's account, not just the user's browser, so when they log in on another device their shopping cart is following them around.
Yes, there are also perfectly fine cases were storing information just in a cookie is fine and preferable, especially since that allows you to scale your server more easily to a cluster of servers without having to worry about where the session information is stored. It depends on what information exactly you are storing.
The usual pattern is
the cookie contains only a unique session identifier (but no useful information itself)
the session storage (server-side) contains the associated data for this session. This can be a) very big and b) hidden from the user/browser and c) trustworthy (because the user cannot just modify it in the browser)
It is preferred to use sessions because the actual values are hidden from the client, and you control when the data expires and becomes invalid. If it was all based on cookies, a user (or hacker) could manipulate their cookie data and then play requests to your site.
I read this article on using Spring Security to "secure" (password-protect) a REST-like service: http://www.baeldung.com/2011/10/31/securing-a-restful-web-service-with-spring-security-3-1-part-3/.
This solution is what I seem to want, however, I noticed that at the bottom of the article, the authentication process is based on a cookie. If you notice, after a user logs in, a cookie is sent back to the user, and the user keeps using this cookie on subsequent request to access the REST endpoints (see the curl commands).
My concern about this approach centers on security; meaning, what's to stop the user from sending this cookie to someone else for use or someone from copying this cookie and using the REST service without proper authentication?
Is there a way to set the cookie (or cookies) such that it is valid for only one user? For example, for only the IP that authenticated correctly? But even this is problematic, as multiple users may share one external IP address.
It looks like the code is just demonstrating how to maintain a session between requests, exactly as your browser would do, by storing the JSESSIONID cookie. So I think your question is really the same as "what's to stop a user from copying the session cookie from their browser and giving it to someone else?". Of course there is nothing to stop them doing that but why would they want to? The same argument applies to any kind of security token. There's nothing to stop them giving away their username and password either which would have the same effect.
In most cases a web service would be stateless, so it wouldn't use session cookies. But OAuth tokens and so on are just as sensitive, often more so since they usually have a longer life span.
So, I have a web application that makes a lot of requests to the server for data. A project requirement is to have very fast server response times. The server is hosted on a cloud based platform.
The app uses sessions to keep track of user authentication once they've logged in. Since it's hosted on a cloud provider, I'm using a cache to back up session storage (in my case it's Auzre cache, but if you're unfamiliar with that think Redis)
The current flow is like this:
The user accesses a resource
Trying to get the session based on the session ID via the cache. This is a cache request.
User is authenticated via session state (if logged in).
Request for data is sent, usually via cache.
Data is returned to the user.
The problem with this approach is that it's hitting the cache twice. Removing the session altogether caused a significant speed improvement (about 50%).
I was considering hitting the cache once, asking for both the key I need for the user, and the SessionID to save the extra round trip. However, I've never seen this approach before, and it requires 'rolling my own session' as I'd have to generate the session IDs and such. I feel like there might be a simpler, easier way.
So, what would be the most efficient way to serve the user a resource and authenticate them?
Note: I'm using ASP.NET MVC/ WebAPI with C# but I don't find that very relevant to the question, so I left the language and platform out of the question because of it.
You would want to combine the authenticate and resource request steps into one single request. Not only is this faster, it is also safer than your implementation. Consider the following scenario:
User authenticate to the server. Result is success.
Authentication is changed. (e.g. user changes password, admin decides to lock the user account, etc.)
User makes a request using the sessionID in step 1.
To ensure that the user is not granted access to the resource, you'd want to authenticate the user precisely at step 3. But that doesn't make sense, you've already authenticated this user previously in step 1...
HTTP, in is core, is designed exactly to do this. There are various ways to pass authentication information along with the request, such as:
Write the authentication information in the content (stupid, but works)
Include authentication in the url, e.g. example.com/pic/123?sessionID=abc (better, but makes your url ugly and long)
Store session info in cookie (better, but what if the client does not support cookie? what about cookie expiration?)
Authenticate HTTP header (my best personal recommendation)
HTTP itself has an authenticate header meant to be compatible with "basic authentication" (it is well defined, look it up if you're interested). But you can implement your own custom header.
Any cache lookup is bound to be slow (compared to computation), so you should omit the cache for the authentication part all together. Your server should be stateless; i.e. do not keep track of login sessions. How do you know if the sessionID is valid? Put a timestamp on it. And to avoid others faking the sessionID, sign it as well.
So, your HTTP request would look something like this (pseudo code):
var request = new HttpRequest();
request.url = "example.com/pic/123";
request.Headers["CustomAuth"] = "id=abc&t=123456789&s=01de45890a";
Implement your own signing method, sort of like a hash function (you can use HMAC), and keep the key securely on the server. If the signature matches, you know you've signed this previously at the login, and it has to be from your server. A timestamp helps you detect session expiration and also protect against replay attacks.
Now in your server, do something like this:
public void Get(){
var authHeader = Request.Headers["CustomAuth"];
if(!validate(authHeader)){
Response.StatusCode = 404;
Response.End();
}else{
//something else
}
}
If you need to do login + session authenticate + resource request in one request, then there're simply just 2 ways for authentication. Users can either provide a username/password combination, or a session key. Think about this scenario, which comes from an API I worked on:
user register with username/password combo
server responds registration success / failure (e.g. username already taken)
if it was a success, user now logins with username/password combo
server returns a session token
Wouldn't it be simpler (and faster) if we do it this way:
user register with username/password combo
if it is success, respond "reg success" and "sessionToken=xxxxxx". if it is failure, respond "reg failure".
I hope this give you some idea.
Also, you can remove the authentication at the server end by modifying / restricting settings on the server to cater to requests coming only from the ip(s) where your web app is hosted. Your web application will let the request pass to server only if its authenticated and hence all the requests reaching the data server will be served automatically without checking for any authentication. In this case you will just need one cache hit to check if the user is authenticated and straight away hit the server.
I am working on a web page that uses a lot of AJAX to communicate with the server. The server, in turn, has an extensive REST/JSON API exposing the different operations called by the web client.
This web site is used by both anonymous and authenticated users. As you might expect, the web service calls issued by authenticated users require authentication, and are thus protected from unauthorized users or applications.
However, the web site has a lot of features that require no authentication, and some of these make use of anonymous web services. The only way I am using to prevent outsiders from calling this web services is by using a CSRF token. I know, the CSRF token is not very useful in this regard... with some time in hand, you can figure out how to consume the web services even if they use a CSRF token.
Of course, you can use a CAPTCHA to prevent applications or bots from autonomously using your web service. However, any human will be able to use it.
Sharing a secret key between client and server, on the other side, would be useless. This, because of the ability of any outsider to read it from the web page source code.
I would like to make these web services as difficult to invoke as posible to any 3rd party application. What would you do besides using the CSRF token? It sounds a little stupid, but hey, maybe it is stupid and I am just losing my time.
Note: given this application uses a browser and not an "executable" as the client, this question is irrelevant to the discussion. I cannot use a secret between server and client (not to my knowledge, at least)
I would take a few steps.
Force https on the site. Automatically redirect any incoming http requests to https ones (the RequireHttps attribute is handy for this)
Each page needs to (securely, hence the https) send a one-time use token to the client, to be used for the page. The script running on the client can hold this in the page memory. Any request coming back sends a hashed & salted response, along with the nonce salt. The server can repeat the steps with the saved token + salt and hash to confirm the request. (much like explunit's answer above)
(It's worth noting that the secure request from a client isn't being authenticated from a user account, merely a token sent with the full page.)
The definition for one-time could either be session or page load, depending on your security vs convenience preference. Tokens should be long and expired fairly quickly to frustrate attackers.
The SSL + Hash(token + nonce) should be enough for your needs.
This is interesting. Below is a crazy suggestion. Remember, your question is also equally crazy.
Your website, once opened through a browser, should generate a long polling connection (Comet programing). This will create a unique session between the browser and the server. When ur JS is making the ajax call, send some token (unique token every time) to the server through the long polling thread. Let the AJAX also send the same token. At the server, get the AJAX token and check whether you have a similar token in you long polling session. If yes, fulfill the request. Any coder can break this. But, it won't be easy. Chances are the freeboarders won't even see these second piece of comet code. You can implement the comet code in such a way it is not easy to detect or understand. When they call ur service, send a 'Service Unavailable' message. They will be confused. Also make the comet code https.
You can also check how long that long polling thread is open. If the session was just opened and you get a ajax call right away, you can assume it is a 3rd party call. It depends on ur website flow. If ur Ajax call happens after 1 second of page load, you can check for that pattern on server side.
Anyone coding for your public api, will have 1 to 2 secret checks that they wouldn't even know and even if they know, they might be discouraged by all the extra coding they have to do.
You might have an easier problem than the one described in the linked question since you don't need to distribute a binary to the users. Even if your app is open source, the HMAC/signature key (in the "Request Signatures" part of that answer) can be controlled by an environment/configuration setting.
To summarize:
The secret key is not actually sent between client and server. Rather, it's used to sign the requests
Be sure that the requests include some unique/random element (your CSRF key probably suffices) so that two requests for the same API data are not identical.
Sign the request with the secret key and append the signature to the request. You linked to a PHP question but not clear if what language you're using. In .Net I would use a HMAC class such as HMACSHA256.
On the API server-side use the same HMAC object to verify that the request was signed with the same secret key.
Maybe you could use counters to keep track of conversations. Only the Server and Clients will be able to predict the next iteration in a conversation. This way, I think, you can prevent third party applications to impersonate someone (Just an idea though).
At the beginning, they start talking at some iteration (i=0, for example).
Every time the client requests something, the counter is incremented by some number in both the server side and the client (i=i+some_number).
And, after a few minutes of no communication, they both know they have to reset the counter (i=0).
This is just an idea based on the concept of RSA and also placing Fraud Detection on your system. The Risk from Authorized users is minimal however they can attempt to make anonymous calls to your web-service too.
For UN-Authorised users : For each web-service call , generate a token say using RSA which changes after some time(can be configured say 30 min). This way prediction of code is minimized. I have not heard of RSA collision till now. Send this token back to the user for his browser session. For further security , we might want to attach a session id with RSA token. Since session ids are unique new anonymous calls would require new session id.
Calls can be tracked using Auditing mechanism. Also per-web service there can be a different RSA setup. How the Algorithm for Fraud Detection would work is a challenge by itself.
For Authorized Users :
Every user should be tracked by his IP Address using Header block. The RSA token principle can be applied.
The solution is very vague but worth considering.
I am currently working on the authentication of an AJAX based site, and was wondering if anybody had any reccomendations on best practices for this sort of thing.
My original approach was a cookie based system. Essentially I set a cookie with an auth code, and every data access changed the cookie. As well, whenever there was a failed authentication, all sessions by that user were de-authenticated, to keep hijackers out. To hijack a session, somebody would have to leave themselves logged in, and a hacker would need to have the very last cookie update sent to spoof a session.
Unfortunatley, due to the nature of AJAX, when making multiple requests quickly, they might come back out of order, setting the cookie wrong, and breaking the session, so I need to reimplement.
My ideas were:
A decidedly less secure session based method
using SSL over the whole site (seems like overkill)
Using an iFrame which is ssl authenticated to do secure transactions (I just sorta assume this is possible, with a little bit of jquery hacking)
The issue is not the data being transferred, the only concern is that somebody might get control over an account that is not theirs.
A decidedly less secure session based method
Personally, I have not found using SSL for the entire site (or most of it) to be overkill. Maybe a while ago when speeds and feeds were slower. Now I wouldn't hesitate to put any part of a site under SSL.
If you've decided that using SSL for the entire site is acceptable, you might consider just using the old "Basic Authentication" where the server returns the 401 response which causes the browser to prompt for username/password. If your application can live with this type of login, is works great for AJAX and all other accesses to your site because the browser handles re-submitting requests with appropriate credentials (and it is safe if you use SSL, but only if you use SSL -- don't use Basic auth with plain http!).
SSL is a must, preventing transparent proxy connections that could be used by several users. Then I'd simply check the incoming ip address with the one that got authenticated.
Re-authenticate:
as soon as the ip address changes
on a time out bigger than n seconds without any request
individually on any important transaction
A common solution is to hash the user's session id and pass that in with every request to ensure the request is coming from a valid user (see this slideshow). This is reasonably secure from a CSRF perspective, but if someone was sniffing the data it could be intercepted. Depending on your needs, ssl is always going to be the most secure method.
What if you put a "generated" timestamp on each of the responses from the server and the AJAX application could always use the cookie with the latest timestamp.
Your best bet is using an SSL connection over a previously authenticated connection with something Apache and/or Tomcat. Form based authentication in either one, with a required SSL connection gives you a secure connection. The webapp can then provide security and identity for the session and the client side Ajax doesn't need to be concerned with security.
You might try reading the book Ajax Security,by Billy Hoffman and Bryan Sullivan. I found it changed my way of thinking about security. There are very specific suggestions for each phase of Ajax.