I went through some resources about JSESSIONID. They say that HTTP and web-servers are stateless. Ok fine, I know this. But then they say- to add a state to these, sessions are used. And there is a session created JSESSIONID by web servers(in java applications). JSESSIONID helps web servers to recognize if the request is coming from the same previous user or a new user. But, this created a doubt in me:
For basic authentication(for example), we send username password with each request, along with JSESSIONID. So, what additional benefit does JSESSIONID adds to that request, if we still need to send credentials with each request. What is the benefit of remembering the client-requests(the idea of using session-cookies)?
Any real-world example, please.
Related
Background: I have a javaee webapp deployed on tomcat which uses form based authentication. When the web server receives a login request, it sends the request to a dedicated authentication service which validates user login (User id and password). After successful authentication user's session is maintained in the web server.
Problem: I have written a simple webpp source code here, to simulate the scenario. On successful login the current HttpSession instance is invalidated and new instance is created. For each request for a post login page, the session is validated. A new JSESSIONID cookie is set which is used to identify the user during the session until session is expired or user logs out. This cookie can easily viewed in browser's dev tools. If I copy the cookie and set this in a different browser via JavaScript (document.cookie="JSESSIONID=xyzz") and then try to access a post login page, the server identifies it as a valid request and session is validated successfully. The post login page is served without user being challenged for user Id and password.
POC: User opens chrome and enter the URL http://localhost:8080/mywebapp/ and logs in with admin and pass1234. On successful log in the home page http://localhost:8080/mywebapp/home is shown. Now the JSESSIONID cookie is copied and set in FireFox. User enters http://localhost:8080/mywebapp/home in Firefox and is shown the home page without being challenged for userId and password.
Question: How can this be prevented wherein same session is getting replicated over multiple browsers?
You can't prevent this specific case of simply copying the cookie from your own browser (or by copying the cookie value from a HTTP payload copypaste/screenshot posted by an ignorant somewhere on the Internet). You can at most prevent the cookie getting hijacked by XSS or man-in-middle attacks.
This all is elaborated in Wikipedia page on the subject Session Hijacking of which I snipped away irrelevant parts (either already enforced by Servlet API, or are simply not applicable here).
Prevention
Methods to prevent session hijacking include:
Encryption of the data traffic passed between the parties by using SSL/TLS; in particular the session key (though ideally all traffic for the entire session[11]). This technique is widely relied-upon by web-based banks and other e-commerce services, because it completely prevents sniffing-style attacks. However, it could still be possible to perform some other kind of session hijack. In response, scientists from the Radboud University Nijmegen proposed in 2013 a way to prevent session hijacking by correlating the application session with the SSL/TLS credentials[12]
(snip, not relevant)
(snip, not relevant)
Some services make secondary checks against the identity of the user. For example, a web server could check with each request made that the IP address of the user matched the one last used during that session. This does not prevent attacks by somebody who shares the same IP address, however, and could be frustrating for users whose IP address is liable to change during a browsing session.
Alternatively, some services will change the value of the cookie with each and every request. This dramatically reduces the window in which an attacker can operate and makes it easy to identify whether an attack has taken place, but can cause other technical problems (for example, two legitimate, closely timed requests from the same client can lead to a token check error on the server).
(snip, not relevant)
In other words:
Use HTTPS instead of HTTP to prevent man-in-middle attacks.
Add a checkbox "Lock my IP" to login form and reject requests from different IP associated with same session in a servlet filter. This only works on users who know themselves they have a fixed IP.
Change session cookie on every request. Interesting at first sight, but breaks when user has same website open in multiple browser tabs/windows in same "session".
Not mentioned, but make sure you don't have a XSS hole anywhere, else it's very easy stealing cookies.
Last but not least, I'd like to make clear that this problem is absolutely not specifically related to Servlet API and the JSESSIONID cookie. All other stateful server side languages/frameworks such as PHP (PHPSESSID) and ASP (ASPSESSIONID) also expose exactly the same security problem. The JSESSIONID was previously (decade ago orso) only a bit more in news because by default it was possible to pass the session identifier along in the URL (which was done to support HTTP session in clients who have cookies disabled). Trouble started when ignorant endusers copypasted the full URL with JSESSIONID inside to share links with others. Since Servlet 3.0 you can turn off JSESSIONID in URLs by enforcing a cookie-only policy.
<session-config>
<tracking-mode>COOKIE</tracking-mode>
</session-config>
See also:
How do servlets work? Instantiation, sessions, shared variables and multithreading
How to prevent adding jsessionid at the end of redirected url
remove jsessionid in url rewrite in spring mvc
What you have stated is called session hijacking. There are many good answers on how to prevent it.
Using same Jsession ID to login into other machine
we can use Encryption or hide JSESSIONID using Browser control.
Thanks
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.
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.
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.
Disclaimer: I'm new to the REST school of thought, and I'm trying to wrap my mind around it.
So, I'm reading this page, Common REST Mistakes, and I've found I'm completely baffled by the section on sessions being irrelevant. This is what the page says:
There should be no need for a client
to "login" or "start a connection."
HTTP authentication is done
automatically on every message. Client
applications are consumers of
resources, not services. Therefore
there is nothing to log in to! Let's
say that you are booking a flight on a
REST web service. You don't create a
new "session" connection to the
service. Rather you ask the "itinerary
creator object" to create you a new
itinerary. You can start filling in
the blanks but then get some totally
different component elsewhere on the
web to fill in some other blanks.
There is no session so there is no
problem of migrating session state
between clients. There is also no
issue of "session affinity" in the
server (though there are still load
balancing issues to continue).
Okay, I get that HTTP authentication is done automatically on every message - but how? Is the username/password sent with every request? Doesn't that just increase attack surface area? I feel like I'm missing part of the puzzle.
Would it be bad to have a REST service, say, /session, that accepts a GET request, where you'd pass in a username/password as part of the request, and returns a session token if the authentication was successful, that could be then passed along with subsequent requests? Does that make sense from a REST point of view, or is that missing the point?
To be RESTful, each HTTP request should carry enough information by itself for its recipient to process it to be in complete harmony with the stateless nature of HTTP.
Okay, I get that HTTP authentication
is done automatically on every message
- but how?
Yes, the username and password is sent with every request. The common methods to do so are basic access authentication and digest access authentication. And yes, an eavesdropper can capture the user's credentials. One would thus encrypt all data sent and received using Transport Layer Security (TLS).
Would it be bad to have a REST
service, say, /session, that accepts a
GET request, where you'd pass in a
username/password as part of the
request, and returns a session token
if the authentication was successful,
that could be then passed along with
subsequent requests? Does that make
sense from a REST point of view, or is
that missing the point?
This would not be RESTful since it carries state but it is however quite common since it's a convenience for users; a user does not have to login each time.
What you describe in a "session token" is commonly referred to as a login cookie. For instance, if you try to login to your Yahoo! account there's a checkbox that says "keep me logged in for 2 weeks". This is essentially saying (in your words) "keep my session token alive for 2 weeks if I login successfully." Web browsers will send such login cookies (and possibly others) with each HTTP request you ask it to make for you.
It is not uncommon for a REST service to require authentication for every HTTP request. For example, Amazon S3 requires that every request have a signature that is derived from the user credentials, the exact request to perform, and the current time. This signature is easy to calculate on the client side, can be quickly verified by the server, and is of limited use to an attacker who intercepts it (since it is based on the current time).
Many people don't understand REST principales very clearly, using a session token doesn't mean always you're stateful, the reason to send username/password with each request is only for authentication and the same for sending a token (generated by login process) just to decide if the client has permission to request data or not, you only violate REST convetions when you use weither username/password or session tokens to decide what data to show !
instead you have to use them only for athentication (to show data or not to show data)
in your case i say YES this is RESTy, but try avoiding using native php sessions in your REST API and start generating your own hashed tokens that expire in determined periode of time!
No, it doesn't miss the point. Google's ClientLogin works in exactly this way with the notable exception that the client is instructed to go to the "/session" using a HTTP 401 response. But this doesn't create a session, it only creates a way for clients to (temporarily) authenticate themselves without passing the credentials in the clear, and for the server to control the validity of these temporary credentials as it sees fit.
Okay, I get that HTTP authentication
is done automatically on every message
- but how?
"Authorization:" HTTP header send by client. Either basic (plain text) or digest.
Would it be bad to have a REST
service, say, /session, that accepts a
GET request, where you'd pass in a
username/password as part of the
request, and returns a session token
if the authentication was successful,
that could be then passed along with
subsequent requests? Does that make
sense from a REST point of view, or is
that missing the point?
The whole idea of session is to make stateful applications using stateless protocol (HTTP) and dumb client (web browser), by maintaining the state on server's side. One of the REST principles is "Every resource is uniquely addressable using a universal syntax for use in hypermedia links". Session variables are something that cannot be accessed via URI. Truly RESTful application would maintain state on client's side, sending all the necessary variables over by HTTP, preferably in the URI.
Example: search with pagination. You'd have URL in form
http://server/search/urlencoded-search-terms/page_num
It's has a lot in common with bookmarkable URLs
I think your suggestion is OK, if you want to control the client session life time. I think that RESTful architecture encourages you to develop stateless applications. As #2pence wrote "each HTTP request should carry enough information by itself for its recipient to process it to be in complete harmony with the stateless nature of HTTP" .
However, not always that is the case, sometimes the application needs to tell when client logs-in or logs-out and to maintain resources such as locks or licenses based on this information. See my follow up question for an example of such case.