Re: [websec] #58: Should we pin only SPKI, or also names

[Trevor Perrin <[e-mail]>]

On Sun, Aug 11, 2013 at 4:34 AM, Tobias Gondrom
<[e-mail]> wrote:
> Hi all,
>
> <no hats>
>
> A small question about pinning to names and uniqueness of "pinned names":
> Under which conditions could the following attack scenario be a problem
> and what would we do about it?
>
> Domain A has bought a cert from CA-11 with the name "super safe" and
> pins to the name instead of the cert.
> CA-11 could be an intermediate for CA-1 with the name "uber super safe".
> Which names could we pin to?
> - the intermediate CA-1 and/or CA-11?
>
> Now wondering whether the following is a problem:
> attacker gains control over CA-2 (either through an attack or through
> government influence) and issues a certificate for an intermediate
> CA-11' with the name "super safe".


Yes, that's a problem.  Gerv also brought up the "DigiCert" name collision.

So using names as a "layer of indirection" to point to a set of
CA-declared keys seems better than trying to pin to names as they
appear in certs.


Trevor