--On Monday, December 09, 2013 22:39 -0500 Phillip Hallam-Baker
<hallam@xxxxxxxxx> wrote:
>...
>> For a similar reason removal of TLD's can't happen as people
>> can still graft on namespace and establish TA's for the
>> grafted on namespace.
>
>
> It is trivial to fix when the validation is taking place in a
> service in the cloud (aka a resolver).
>
> Rather less easy to do if people drink the DANE cool-aid and
> do the job at the end point.
>
> Now you can take this point as either arguing against doing
> DANE or considering the risk and deploying the appropriate
> control. But you do have to consider it.
>
>
> What you are in effect asserting is that the resolver
> providers are the apex of the trust chain and so there is a
> diffuse trust surface rather than a sharp point. Which is true
> when the validation takes place in the resolver.
I am probably going to regret getting involved in this thread,
but I would draw two rather different conclusions from the above
and a number of other comments:
(1) We have seriously oversold DNSSEC as a data quality and
reliability mechanism when it is merely a transmission integrity
mechanism. The former is about the DNS and associated
registration database (e.g., "whois") records being accurate,
secure, and maybe even information-containing. The latter is
merely about an assurance that the data one receives hasn't been
altered in transit in the DNS.
Now most of the people who have been involved in the design and
implementation of DNSSEC have been quite careful about the
above, at least most of the time. But sometimes they are sloppy
about their language, sometimes they say "DNNSEC" and people
hear "DNS Security" and make inferences to data quality. More
important, there is an (illogical) chain of reasoning from
"DNSSEC is in use" to "[now] the DNS is secure" to "all of the
data provided by the DNS or its supplemental databases are of
high quality".
While the integrity checks of DNSSEC provide some protection
against some types of attacks on the "data quality" part of the
DNS environment, the attacks they protect against are very
difficult. An attacker with the resources to apply them would
almost certainly find it easier, less resource-expensive, and
harder to detect to attack registry databases (before data are
entered into DNS zones and signed), registrar practices, or
post-validation servers. Non-technical attacks, such as the
oft-cited hypothetical NSL, are easily applied at those points
as well -- much more easily than tampering with keys or
signatures.
(2) In a different version of some of the comments on the
thread, the "where to validate" question is important. If one
tries to validate at the endpoints, endpoint systems, including
embedded ones, should have the code and resources needed to
validate certs and handle rollovers, even under hostile
conditions, and that isn't easy. If one relies on intermediate,
especially third-party, servers to validate, than much of the
expected integrity protection is gone... and the number of times
such servers have been compromised would make this a
non-theoretical problem even without concerns about
governmental-type attacks (NSL and otherwise) on those servers.
No easy solutions here.
I don't know where that combination of situations leaves
initiatives like DANE, but I suspect we should be looking at
trust conditions and relationships a lot more carefully than the
discussions and claims I've seen suggest we have been doing.
john