Re: ACTION-240 :TLS errors...

On 2007-07-09 15:47:55 -0400, Johnathan Nightingale wrote:

> What would your recommendation be for SS certs?  We toyed with
> the idea of saying that an SS cert connection should be quietly
> encrypted, but present no security indicators, since we have no
> reason to trust it.  The problem is that this enables the MitM
> scenario nicely.  A diligent user is careful never to visit her
> bank except via her trusted https bookmark, or by typing in the
> URL manually.  If someone tried to DNS spoof with a straight http
> connection, the attempt would fail, since the https connection
> would fall on the floor.  But if SS certs are quietly allowed
> through, the attacker can spin a SS-cert for bankofamerica.com
> and the connection would succeed (albeit without the usual
> context indicators).  This is the kind of thing that can't happen
> with a cert issued by a trusted CA, even a $20 one.

Isn't this a poster child use case for exploiting browser state?
E.g., exploiting the knowledge that a certain domain in connection
with HTTPS used to have a CA-based cert, and warning when that
changes?

-- 
Thomas Roessler, W3C  <tlr@w3.org>

Received on Wednesday, 11 July 2007 14:50:08 UTC