Markus Stumpf <maex-lists-email-ietf-smtp(_at_)Space(_dot_)Net> writes:
On Thu, May 06, 2004 at 09:11:54PM -0700, Russ Allbery wrote:
I'm very suspicious of any place where TLS is done expecting any
certificate other than the one matching the name that the user typed
into their configuration or program, since it opens an avenue for
attack.
How about
www.example.COM CNAME cname.example.ORG.
cname.example.ORG A 10.0.0.1
https://www.example.com/
Will the browser complain or is it happy as long as
cname.example.com
has a valid cert?
The browser will complain, in the absence of implementation by both the
server and the client of the new server_name TLS extension, unless that
web site actually presents a certificate for www.example.com.
Didn't find a setup like that for the moment, so I can't check myself,
but maybe someone on this list knows one ...
This is the reason why you didn't find an example like that. This is why
web sites that require TLS have a separate IP address for every host name.
The same security problems apply as with an attacker being able to
inject a MX record.
Exactly.
--
Russ Allbery (rra(_at_)stanford(_dot_)edu)
<http://www.eyrie.org/~eagle/>