Re: UMP / CORS: Implementor Interest

On Wed, Apr 21, 2010 at 2:43 PM, Dirk Pranke <> wrote:
> Similarly, if it is really your intent to stop CORS from getting
> implemented, you're going to have to sell that harder, because (to
> switch metaphors), if that ship hasn't already sailed, it is at least
> boarding.

I'd like to check the status of this discussion with the WG.

I believe I've made a strong case that using CORS in a natural way can
result in CSRF-like (Confused Deputy) vulnerabilities. There are
several ways in which the pattern can manifest, but one of the
simplest is A makes a request to B and includes some of the received
data in a subsequent request to C. If credentials are used, A is
applying all of its authority to identifiers selected by B. If B might
be an attacker, there's a Confused Deputy vulnerability. There's
nothing C can do to detect the attack server-side.

Do WG members understand and accept the above? My impression from the
discussion is yes, but people think it's a problem for Web developers
to deal with and CORS has no responsibility here. Is that accurate? If
so, can I convince WG members that we have a responsibility to provide
easy-to-use *and* safe APIs to Web developers?


"Waterken News: Capability security on the Web"

Received on Wednesday, 21 April 2010 23:58:15 UTC