In my web application, there's a link sending a redirect (302 to another GET request) together with some cookies. It works fine, except when used from MS Access by a guy I remotely work with. I know close to nothing about what and how he does, I only know that he uses Application.FollowHyperlink.
The link from Access should be opened in a browser, but after the redirect, there seem to be no cookies there. When used normally, there's no problem. Can it be like that Access handles the link itself and sends the redirected URL to the browser?
Maybe a stupid question, but I have no idea about Access (never ever seen it) and I'm sitting only on the server side. There's nothing interesting in the server logs...
The problem was MS doing some complicated things like here instead of simply opening an URL in a browser. Access accesses the page, sees the new URL, and gets and eats all cookies. While digesting the cookies, it points the browser to the new URL. The browser has no cookies and no access to anything.
This summarizes it nicely:
This problem occurs because of missing session cookies for the Web server. This problem is specific to certain Web-server designs that depend on cookie information instead of authentication information or that depend on cookie information plus authentication information.
To me it sounds like "works with MS only", though I'm not exactly sure what "authentication" they mean.
Related
I want to automate logging into a website and retrieving certain data.
I thought the way to do this would be to sniff the HTTP requests so I know where the login form is being POSTed to so I can do the same using NodeJS/Java/Python.
However I can't seem to find the HTTP request that handles it.
The site seems to use some Java-applet and a lot of Javascript.
This is the site: link
Should I have a different approach?
Also also wonder about storing a cookie session, and sending it with each HTTP request after logging in.
I'm sorry if I am not to clear, I will try to explain myself further and edit this post if needed.
You can use the developer console (hit F12) in Chrome (this works also in other browsers) and then click the "Network" tab. There you see all network calls.
To detect what http requests are performed from a mobile device, you can use a proxy like Charles Proxy.
Also be aware that if you post from nodejs the cookies won't be set in the users browser.
I was using Fiddler see on-the-field how web sites use cookies in their login systems. Although I have some HTTP knowledge, I'm just just learning about cookies and how they are used within sites.
Initially I assumed that when submitting the form I'd see no cookies sent, and that the response would contain some cookie info that would then be saved by the browser.
In fact, just the opposite seems to be the case. It is the request that's sending in info, and the server returns nothing.
When fiddling about the issue, I noticed that even with a browser cleaned of cookies, the client seems to always be sending a RequestVerificationToken to the server, even when just looking around withot being signed in.
Why is this so?
Thanks
Cookies are set by the server with the Set-Cookie HTTP response header, and they can also be set through JavaScript.
A cookie has a path. If the path of a cookie matches the path of the document that is being requested, then the browser will include all such cookies in the Cookie HTTP request header.
You must make sure to be careful when setting or modifying cookies in order to avoid XSS attacks against your users. As such, it might be useful to include a hidden and unique secret within your login forms, and use such secret prior to setting any cookies. Alternatively, you can simply check that HTTP Referer header matches your site. Otherwise, a malicious site can copy your form fields, and create a login form to your site on their site, and do form.submit(), effectively logging out your user, or performing a brute-force attack on your site through unsuspecting users that happen to be visiting the malicious web-site.
The RequestVerificationToken that you mention has nothing to do with HTTP Cookies, it sounds like an implementation detail that some sites written in some specific site-scripting language use to protect their cookie-setting-pages against XSS attacks.
When you hit a page on a website, usually the response(the page that you landed on) contains instructions from the server in the http response to set some cookies.
Websites may use these to track information about your behavior or save your preferences for future or short term.
Website may do so on your first visit to any page or on you visit to a particular page.
The browser would then send all cookies that have been set with subsequent request to that domain.
Think about it, HTTP is stateless. You landed on Home Page and clicked set by background to blue. Then you went to a gallery page. The next request goes to your server but the server does not have any idea about your background color preference.
Now if the request contained a cookie telling the server about your preference, the website would serve you your right preference.
Now this is one way. Another way is a session. Think of cookies as information stored on client side. But what if server needs to store some temporary info about you on server side. Info that is maybe too sensitive to be exposed in cookies, which are local and easily intercepted.
Now you would ask, but HTTP is stateless. Correct. But Server could keep info about you in a map, whose is the session id. this session id is set on the client side as a cookie or resent with every request in parameters. Now server is only getting the key but can lookup information about you, like whether you are logged in successfully, what is your role in the system etc.
Wow, that a lot of text, but I hope it helped. If not feel free to ask more.
I would like to create web application with admin/checkout sections being secured. Assuming I have SSL set up for subdomain.mydomain.com I would like to make sure that all that top-secret stuff ;) like checkout pages and admin section is transferred securely. Would it be ok to structure my application as below?
subdomain.mydomain.com
adminSectionFolder
adminPage1.php
adminPage2.php
checkoutPagesFolder
checkoutPage1.php
checkoutPage2.php
checkoutPage3.php
homepage.php
loginPage.php
someOtherPage.php
someNonSecureFolder
nonSecurePage1.php
nonSecurePage2.php
nonSecurePage3.php
imagesFolder
image1.jpg
image2.jpg
image3.jpg
Users would access my web application via http as there is no need for SSL for homepage and similar. Checkout/admin pages would have to be accessed via https though (that I would ensure via .htaccess redirects). I would also like to have login form on every page of the site, including non-secure pages. Now my questions are:
if I have form on non-secure page e.g http://subdomain.mydomain.com/homepage.php and that form sends data to https://subdomain.mydomain.com/loginPage.php, is data being send encrypted as if it were sent from https://subdomain.mydomain.com/homepage.php? I do realize users will not see padlock, but browser still should encrypt it, is it right?
EDIT: my apologies.. above in bold I originally typed http but meant https, my bad
2.If on secure page loginPage.php (or any other accessed via https for that instance) I created session, session ID would be assigned, and in case of my web app. something like username of the logged in user. Would I be able to access these session variable from http://subdomain.mydomain.com/homepage.php to for example display greeting message? If session ID is stored in cookies then it would be trouble I assume, but could someone clarify how it should be done? It seems important to have username and password send over SSL.
3.Related to above question I think.. would it actually make any sense to have login secured via SSL so usenrame/password would be transferred securely, and then session ID being transferred with no SSL? I mean wouldnt it be the same really if someone caught username and password being transferred, or caught session ID? Please let me know if I make sense here cause it feels like I'm missing something important.
EDIT: I came up with idea but again please let me know if that would work. Having above, so assuming that sharing session between http and https is as secure as login in user via plain http (not https), I guess on all non secure pages, like homepage etc. I could check if user is already logged in, and if so from php redirect to https version of same page. So user fills in login form from homepage.php, over ssl details are send to backend so probably https://.../homepage.php. Trying to access http://.../someOtherPage.php script would always check if session is created and if so redirect user to https version of this page so https://.../someOtherPage.php. Would that work?
4.To avoid browser popping message "this page contains non secure items..." my links to css, images and all assets, e.g. in case of http://subdomain.mydomain.com/checkoutPage1.php should be absolute so "/images/image1.jpg" or relative so "../images/image1.jpg"? I guess one of those would have to work :)
wow that's long post, thanks for your patience if you got that far and any answers :) oh yeh and I use php/apache on shared hosting
If the SSL termination is on the webserver itself, then you'll probably need to configure seperate document roots for the secure and non-secure parts - while you could specify that these both reference the same physical directory, you're going to get tied in knots switching between the parts. Similarly if your SSL termination is before the webserver you've got no systematic separation of the secure and non-secure parts.
Its a lot tidier to separate out the secure and non-secure parts into seperate trees - note that if you have non-SSL content on a secure page, the users will get warning messages.
Regards your specific questions
NO - whether data is encrypted depends on where it is GOING TO, not where it is coming from
YES - but only if you DO NOT set the secure_only cookie flag - note that if you follow my recommendations above, you also need to ensure that the cookie path is set to '/'
the page which processes the username and password MUST be secure. If not then you are exposing your clients authentication details (most people use the same password for all the sites they visit) and anyone running a network sniffer or proxy would have access.
Your EDIT left me a bit confused. SSL is computationally expensive and slow - so you want to minimise its use - but you need to balance this with your users perception of security - don't keep switching from SSL to non-SSL, and although its perfectly secure for users to enter their details on a page served up by non-SSL which sends to a SSL page, the users may not understand this distinction.
See the first part of my answer above.
C.
I have an asp .net webforms app that uses forms authentication. For a small number of users we have a problem where they log in, they navigate to a couple of pages and then they are asked to log in again. Once logged in for a second time they seem to be able to stay logged in as expected. They shouldn't be asked to login the second time.
This is a single server, no web farms, nothing tricky.
This only happens to a few users, but it does seem to be all users from the same building. I am unable to replicate this and at this point might even start to deny that t was happening if one of our trainers hadn't watched it happen to a couple of customers.
Has anyone else seen anything like this?
I am also seeing a lot of "Membership credential verification failed." errors in the event log. This may be related, but all the googling I've done seems to point to web farms and the like, not a single server.
UPDATE
There is no proxy server, the IIS server and the browser (IE8) are both on the same machine.
The AV software installed is Symantec Endpoint, on one machine, on the other the user didn't have any AV at all (AV Fail!).
The browser is IE 8 with no frills, not a single addin that didn't come with the default installation.
Both session and user login time-outs are set to 30 mins and the problem happens within 1 min of the user logging on.
Logging shows the user to only have one IP address.
I have tried the sessionMode in all it's variations, this doesn't seem to make any difference.
Something has to be causing ASP.NET to think these users have new sessions or their authentication cookie is getting invalidated. Here a a few things I can think to check:
Are the users accessing the site through a proxy server? One of our customers has a proxy that will sometimes close all open connections causing ASP.NET to see the session as new.
Could an overly agressive anti-virus, anti-spyware product be "eating" the session authentication cookie?
Do they have a cookie manager browser add-in that is causing the authentication cookie to disappear or change?
Sounds basic but I've seen this happen because of site timeouts being set too short. If the user sits on the page for longer than the timeout, they will be forced to logon again. And this could be specific to a page when that page presents a large amount of data that takes a while for them to go through.
One other thing I just thought of, have you allowed multiple worker processes for the ASP.NET process (aka web gardens)? If so, the same constraints as with a web farm would apply for authentication.
Crack open Fiddler from the problem user's PC and see what's getting passed in the headers. My bet is on a proxy server and or networking issue.
Are the users possibly coming from a dynamic ip address? I've seen problems where the users sessions get messed up because the IP address that they're accessing the site from changes for some reason.
Are the people this is happening using a browser that's somehow different (different browser, different version, different extensions)? That could be a clue.
In general, when the problem is somewhat reproducible or at least predictable, I use Http Fiddler. Install it on a client machine, turn it on, and start browsing (this works via a system proxy - so it'll work for firefox, IE and any other proxy-supporting browsers alike). Fiddler will record all http traffic between client and server, and you can then peruse such a session later on to find any oddities.
It's a long shot, but one thing I've seen happen occasionally that can lead to these sorts of unpredictable errors is scripting parallelization issues: sometimes buttons + links have onclick handlers which cause a post-back. If you have several such handlers that fire on the same event - in particular when the default event still fires additionally to your custom onclick or whatnot - you may be causing several postbacks when it appears to be just a single postback. That can cause all kinds of unpredictable weirdness as it's not entirely clear which request ends up "winning" - and some odd errors may cause a session to terminate. Since this behaviour is very browser + network latency sensitive, it seems quite unpredictable when it occurs.
Delete the cookie on the client PC's that are playing up
ASP.NET Forms Authentication can redirect users to the login page if they do not have the credentials to access a specific page. It does this so that users who may have more than one login are given the opportunity to login with another account which may have the appropriate access. Basic question I know, but are the users using the same credentials the second time they log in?
Its possible that you have don't have specifically specified asp.net to use cookie based session but are allowing either cookie or cookieless sessions.
In the later case the session id is embedded in the Url. The type of issues you are experiences might be explained by that. Basically depending on how you define your links, some of them would not get the session id, so the user would get a new session when using those links - or maybe during a redirect. That could explain why at specific parts of your site the users loose their session.
If you have the mixed mode enabled, try setting it to only cookieless and go through your site.
Update: Based on the extra info posted there is surely more info needed for it. Some extra things to check:
Are you using subdomains, if that's the case the cookie might not be configured to allow that and that doesn't fail in all environments.
If you are using in-process session, make sure there isn't a bug in the application causing it to restart the process
Maybe what's causing it to ask for login again is an authorization check, and you have an issue on some roles related code
Is it possible that the user is just opening a separate window? ;)
To rule out the possibility of the browser or a browser addon messing things up, have you checked their User Agent strings? If they are randomly distributed it might not cause the problem, but if they're all the same, this might be a hint too.
When do you initially get assigned your unique http cookies when visiting a website?
I'm asking this in the sense of when creating a gui auth login from a website. Do you get your cookies the moment you visit the website? If so, if you don't visit the website by homepage and go straight to the http://website.com/login.php form, do you initially also get your cookies there if you haven't received them yet?
On load of the the first page that sets a cookie.
It will be sent along with the content of that page, in the HTTP header.
In PHP:
You can set a cookie any time before sending output to the browser.
You can read it (via $_COOKIE) any time after setting it, including in the same page load.
Just remember that if you read it in the same page load where you set it, you are reading it from the current process, and not from the client's cookie, which won't have been sent yet.
The server/application can set cookies whenever your browser makes an http request. In other words, the answer is implementation-dependent.
I would suggest that you take a look at Fiddler (or some other http tracing tool) to better understand the interaction.
There is no correct answer to this. It is an implementation detail that no two websites (using different base code) do the same way. Variables include the implementation system/language (ASP, PHP, Python, Ruby, etc), use of standardized (or custom) libraries, how security-minded the website is, how long ago the website was written, etc.
Most websites will set your session cookie no matter what page you first arrive from. There are many ways to do this but all involve every possible entry point calling common routines in the website's source code for handling sessions, permissions, navigation, logins, etc.
Having said that, I'm there a significant number of websites that do not set any cookies until you do something that needs to be remembered (login, adding a product to a shopping cart, setting a preference, etc).
How you should do it depends on what is important to your website. There is no single answer to this.
Here's the official standard for cookies and their behaviors:
http://www.ietf.org/rfc/rfc2965.txt
Most browsers will try to conform to this standard as closely as possible, but note that it is up to the implementer. If there are bugs, then of course the behavior is different.
I think the thing you're looking for is that cookies are passed in with the request as long as the domains or URI are the same.
As someone else alluded to, cookies can be manipulated and are inherently insecure. Don't use them as a way for security. You can keep track that they've been logged in successfully with them, but you should put an expiration date on that fact.