There have been a few requests for an XHR which does not expose session data to 
the target. I believe IE9 has an interface for this; I know it's been requested 
on chromium bug list.



On Jun 15, 2011, at 9:18 AM, Boris Zbarsky <[email protected]> wrote:

> On 6/15/11 6:43 AM, David Bruant wrote:
>> Could someone explain how running in a web browser justify such a
>> difference? For instance, could someone explain a threat particular to
>> cross-origin XHR in web browser?
> 
> Off the top of my head:
> 
> 1)  XHR in the web browser sends the user's cookies, HTTP auth credentials, 
> etc. with the request.  Which means that if you're logged in to some site A, 
> and cross-site XHR to that site is allowed from some other other site B, then 
> B can access all the information you can access due to being logged in to 
> site A.
> 
> 2)  XHR in the web browser gives (at the moment, at least) sites that are 
> outside a firewall that your browser is behind the ability to make requests 
> to hosts that are behind the firewall.
> 
> Item 2 is somewhat of an issue for installed apps as well, of course, but 
> installing an app is a trust decision.  I would imagine browsers could relax 
> some of these restrictions if a similar trust decision is explicitly made for 
> a non-locally-hosted app.
> 
> Item 1 is pretty specific to a web browser; the only way to avoid that issue 
> is to run the app's XHRs in a special mode (effectively treating it as not 
> running in the browser at all).
> 
> -Boris
> 

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