Re: To cookie or not to cookie

Brad Porter wrote:
> Historically the user-agents have not been in the
> position of stating or attempting to enforce privacy policy. 

Historically browser have absolutely forbidden cross-site XHR; the
same-origin policy _is_ a privacy policy and browser enforce it.

If this new feature causes users harm because of a careless site the
message the world gets will first be "Don't use Firefox on
MySpace/Yahoo/whoever until the site is fixed" which quickly morphs to
"BrowserX is safer than Firefox" because those users will not want to stop
getting their data.

I know that if we don't send cookies with XSXHR Firefox users aren't at
much more risk from this new Mozilla-only browser feature. It may not be
all that useful without cookies, but _I_ have not put users at risk.

Given the repeated inability of sites to get the XSS issue right I don't
have a lot of confidence they'll implement XSXHR correctly even if it
requires opt-in by the site (the use-history of flash's crossdomain.xml is
not exactly comforting). Convince me that the benefit of sending browser
authentication outweighs the risk of the additional attack surface.
Especially given that any substantial use will have to come up with a
completely different mechanism for other browsers anyway -- only niche
sites can afford to rely on a Firefox-only (for now) feature.

-Dan Veditz