I work for an e-commerce site. Part of what we do is to offer customized items to some clients. Recently some non-technical management promised that we could incorporate our check-out process into one such client's website. The only way we've figured out how to do this is by using an iframe (I know, I don't like it either). The issue is that most customers of this site are unable to check out because we use cookies to determine which custom items to display. Browsers are recognizing our cookies as third party and almost everybody has third party cookies turned off, as they should. I'm going to be shocked if the answer is yes, but is there any workaround for this? ie can the site hosting our iframe somehow supply the necessary cookie?
Try an invisible, interstitial page.
Essentially the hosting site would issue a redirect to a site within your domain, which is then free to set cookies (because at this point is is actually the first party). Then your site immediately redirects back to the hosting site. At this point your newly-created cookies will be invisible to the hosting site but visible to your iFramed page henceforth.
Unfortunately the hosting site will have to do this every time a cookie is to be updated but the double-redirect can happen so quickly they'll hardly notice. Hopefully your system only needs the cookies to be set once.
Instead of using a cookie, pass the information in the each url request as name/value pairs.
It is a bit of a pain to add the name/value to every url...I know...oh well...it will work.
I'm going to be shocked if the answer is yes, but is there any workaround for this? ie can the site hosting our iframe somehow supply the necessary cookie?
Your iframed page itself, which is the third party in this scenario, could send a P3P Cookie Policy header – some browsers then accept third-party cookies by default, whereas others (mainly Safari) will not be convinced to do so at all if not by the user manipulating the default settings themselves.
What you could also do, is pass the session id not (only) by cookie, but as a GET or POST parameter as well – f.e. under PHP this can be done quite easily by configuring the session options. You should consider if that’s worth the slightly increased risk of session stealing.
The interstitial page solution should work but it might be a lot of trouble for your hosting site, so here's another solution that will allow you to work cookieless.
Write an HttpModule that responds to the BeginRequest event, reads the querystring, and inserts corresponding cookie headers into the Context.HttpRequest object (Note: you can't use AddCookie, you have to use AddHeader, because cookies added by a module directly are disposed of before they hit your application proper). That way the hosting site can simply issue a request (within the iFrame) that contains the necessary value in the querystring, the module will convert it into a cookie (that only exists in memory, not on the wire), and your application will be deceived into thinking that there's a cookie there. No code changes required, you just need to add the module in web.config.
This only works if you are using IIS 7.0+ in integrated pipeline mode. If you're on an earlier version of IIS or if you have to run in classic mode, you'll need an ISAPI filter instead.
Ryan , John
For the Chrome v80 update with SameSite flags, want to set the samesite=none;secure for the site hosting our iframe and somehow supply the necessary samesite=none;secure cookie. We have apache 2.2 and tomcat 6 setup, so would appreciate a solution and advice on how to make it work. Currently with flag enabled the iFrame is not punching out successfully.
Thanks
Related
I am very confused as to how Safari ITP 2.3 works in certain respects, and why sites can’t easily circumvent it. I don’t understand under what circumstances limits are applied, what the exact limits are, to what they are applied, and for how long.
To clarify my question I broke it down into several cases. I will be referring to Apple’s official blog post about ITP 2.3 [1] which you can quote from, but feel free to link to any other authoritative or factually correct sources in your answer.
For third-party sites loaded in iframes:
Why can’t they just use localStorage to store the values of cookies, and send this data back and forth not as actual browser cookie headers 🍪, but as data in the body of the request or a header like Set-AuxCookie? Similarly, they can parse the response to updaye localStorage. What limits does ITP actually place on localStorage in third party iframes?
If the localStorage is frequently purged (see question 1), why can’t they simply use postMessage to tell a script on the enclosing website to store some information (perhaps encrypted) and then spit it back whenever it loads an iframe?
For sites that use link decoration
I still don’t understand what the limits on localStorage are in third party sites in iframes, which did NOT get classified as link decorator sites. But let’s say they are link decorator sites. According to [1] Apple only start limiting stuff further if there is a querystring or fragment. But can’t a website rather trivially store this information in the URL path before the querystring, ie /in/here without ?in=here … certainly large companies like Google can trivially choose to do that?
In the case a site has been labeled as a tracking site, does that mean all its non-cookie data is limited to 7 days? What about cookies set by the server, aren’t they exempted? So then simply make a request to your server to set the cookie instead of using Javascript. After all, the operator of the site is very likely to also have access to its HTTP server and app code.
For all sites
Why can’t a service like Google Analytics or Facebook’s widgets simply convince a site to additional add a CNAME to their DNS and get Google’s and Facebook’s servers under a subdomain like gmail.mysite.com or analytics.mysite.com ? And then boom, they can read and set cookies again, in some cases even on the top-level domain for website owners who don’t know better. Doesn’t this completely defeat the goals of Apple’s ITP, since Google and Facebook have now become a “second party” in some sense?
Here on StackOverflow, when we log out on iOS Safari the StackOverflow network is able to log out of multiple sites at once … how is that even accomplished if no one can track users across websites? I have heard it said that “second party cookies” still can be stored but what exactly makes a second party cookie different from a third party?
My question is broken down into 6 cases but the overall theme is, in each case: how does Apple’s latest ITP work in that case, and how does it actually block all cases of potentially malicious tracking (to the point where a well-funded company can’t just do the workarounds above) while at the same time allowing legitimate use cases?
[1] https://webkit.org/blog/9521/intelligent-tracking-prevention-2-3/
I am not sure if the below answers are correct, please comment if they are not:
It seems applications can use localStorage with no problem, up to 7 days. But it won’t be persisted across multiple enclosing domains. I would even recommend using sessionStorage, since the goal is just to have nothing more than a seamless session. You can then roll your own cookie mechanism using a different set of headers, the only thing you can’t implement is http-only cookies.
They can, but ITP won’t let the JavaScript on the enclosing page store cookies (at least, not if your third party domain was flagged as a tracker by Safari).
Yeah, the description of “link decoration” technically doesn’t mention this workaround, but probably Apple has or will update its classifier to handle this workaround.
Yes, if a first-party webpage will send a request to the server and it sets a cookie in the response headers, then these aren’t blocked by ITP, even if it has an iframe to a tracking site. They say that’s not their goal.
Yes, in fact your first-party site can just let your site redirect to google.com and back quickly (like with oAuth) and thereby inform Google of whatever you wanted, without cookies. Google’s JavaScript can do this as well, if you allow it. Then the JavaScript can just load your google-hosted subdomain in an iframe and set a cookie that persists for years, tracking the user. However, ITP 2.3 seems to have also added mitigation to this, so you might use A records instead? https://cookiesaver.io/archives/analytics-guides/cname-cloaking-mitigation-eliminates-safari-itp-workarounds/
Probably the StackExchange network uses a version of #5
ASP.NET Core 2.1
I think this gets set automatically. How do I prevent that?
Just came across the same issue. My 100% cookie-free website had a cookie, created by ASP.NET Core.
As #mark-g pointed out in his comment, it is mainly added to support GDPR: Let users of your web page opt-in/out for the allowance to collect and keep data about them.
In all usual cases I'd recommend to go this route as designed by Microsoft. Keep the ASP.NET cookie and make use of the _CookieConsentPartial.cshtml for all personal data you might want to keep about the users.
In my special case, I have a very simple web page. No data is collected, also not from any third parties. I dont need the cookie consent and the ASP.NET cookie. In this case, can remove this cookie just by commenting out one line:
In Startup.cs comment out the line:
// app.UseCookiePolicy(); No cookies used at all!
Then clear all caches and remove the cookie, reload the page and it is gone.
I would like to set a specific cookie domain for my cookies, because this might solve some issues our site seems to have with IE8. Django seems to have a setting called SESSION_COOKIE_DOMAIN which can be set to obtain this. The problem however is that our site contains multiple subsites which have alternative domain names. So my question is, how can I manage this? I would like to have a standard cookie domain per domain, because I fear browsers like IE8 will reject cookies which aren't from the same domain (quicker).
I will do research myself, but I wondered if anyone perhaps has experience.
Update:
What I actually want to do is to make django store cookies for domain1 when I visit domain1.com etcetera for the other domains. I think it should be as easy as to use the current client domain when storing cookies. I doubt however that django offers such functionality without modification... Maybe I could build a middleware class that changes the global setting to the current domain..
Update:
This question and answer helped me out:
Changing Django settings variable dynamically based on request for multiple site
Thanks for help :)
Cookies can't be stored or retrieved for other domain names. In other words, if I am at yahoo.com I can't get the cookie for google.com. However, foo.yahoo.com and bar.yahoo.com can both retrieve cookies saved at .yahoo.com.
If you are running a website with multiple subsites, if they all share the same basic domain (i.e. site1.domain.com, site2.domain.com, etc) you should use that domain for SESSION_COOKIE_DOMAIN. But if they have different domains, it's basically impossible for them to share cookies without using some other method of getting the cookies. You can, for example, include images or scripts that point to a central site, and that site can store and retrieve the cookies, which are made available to the rest of the page via JavaScript.
If you must keep these alternate domain names, you can always set your web server to redirect immediately from these alternate domain names to the shared standard domain. This is easy to do with mod_rewrite.
I have an interesting conundrum.
We have a site that is a completely separate domain, we'll say http://www.x.com and our own site that is http://www.y.com. The y.com site is actually a classic ASP site, and we aren't converting it to .NET at this time.
The problem is that there is a link on x.com that redirects to y.com from a members area. We want to "authenticate" the user to make sure they are a member from the other site. If they are, they are directed to a members area on y.com. If not, they have to provide login information on y.com.
Cookies obviously don't work due to the cross domain security, but is there a way around this? I've also looked at a service for tokens, but I'm not sure exactly how that works in Classic ASP. Any ideas or suggestions?
What I did when I needed to pass information cross domain what so hash the information into one variable and pass the url/page as another variable as a post into a page on the y.com. That page would unhash the data, set the cookies and session variables, and then do a redirect or server.transfer to the page that was passed. The same can work going from y.com to x.com.
We have several websites on different domains and I'd like to be able to track users' movements on these sites.
Obviously cookies are not feasable, because they don't cross domain borders.
I could look at a combination of IP address and User Agent, but there are some cases where that does not work.
I don't want to use flash or other plugins.
Any ideas? Or am I doomed to rely on the IP/User_Agent combination?
You can designate one domain or subdomain to tracking and have it serve a 1x1 pixel image which you include in all pages you would like to track. Serve a cookie with the image, look at the tracking domain's server logs, voilà.
This solution requires no JavaScript, and works even if the user disables third-party cookies.
First, let's make sure the user agent is sending cookies:
If getCookie("c") == null then setCookie("c", "anyValue")
Then let the request finish (aka wait for next request)
Let's call our tracker cookie uaid.
If GET http://child.com/any-page and getCookie("c") is not null and getCookie("uaid") is null...
Redirect to http://parent.com/give-me-a-uaid?returnTo=http://child.com/any-page
On http://parent.com/give-me-a-uaid, check for cookie uaid
If not exists, create it and add it to response. If it exists, get its value.
Redirect to http://child.com/any-page?uaid=valueOfParentsUAIDCookie
Child.com sets cookie uaid with valueOfParentsUAIDCookie
Redirect to http://child.com/any-page
And of course, you are validating input, and white-listing your redirect URLs :)
Flows:
This question is closely related to the Question Accessing Domain Cookies within an iFrame on Internet Explorer.
For Internet Explorer I need to take P3P Policies into account and set an additional P3P HTTP-Header to allow images to set cookies across domain borders. Then I can use simon's suggestion.
You can follow the same concept used in Google Analytics. Injecting javascript in the pages you want to track.
You do not give any context to your situation -just the basic problem. So it is difficult to give an answer that clearly fits. However, here are some techniques/mechanisms for passing information from one page to another, regardless of what domain is involved.
include hyperlink to a 1x1 pixel transparent gif image (sometimes called a "beacon")
rely on referrer information in HTTP request headers to identify page hyperlink is on
include extra parameters in hyperlinks to other site - assuming you run both sites
buy services of a company like Akamai to do user tracking for you
possibly use cross domain cookie mechanism in the future if standard is ever approved
Which techniques really come down to whether you can place software on all of the sites (servers) that the user will visit where you have interest - or you cannot place your software on all of them.