--On Saturday, August 09, 2014 12:31 -0400 Steve Crocker
<steve(_at_)shinkuro(_dot_)com> wrote:
The authenticity and integrity go hand in hand. The party
looking up a domain name wants to know if the answer is
correct. "Correct" in this context means that it was
provided by the party that is authorized to provide it, i.e.
the domain owner, and that the information hasn't been
modified along the path to the user. That's integrity and
authenticity combined.
Steve, while I clearly agree with the above, I was trying to get
at the point that there are other elements that people might
reasonably consider part of authenticity. One is whether the
apparent domain is what it appears to be. Another is whether
the apparent domain owner is who it appears or claims to be.
That, in turn, is closely connected to the question of whether
there is enough information available to even determine what
ownership assertion is being made, i.e., whether the
user-accessible part of the registry database contains
information about the domain owner or merely some proxy or
"hidden registration" information that points to an entity that
conceals identities for hundreds or thousands of such domains.
From those perspectives, a registrar or registry who might
collude with a criminal registrant to create deliberately
deceptive names and associated registration data (or whose
procedures allow similar results without explicit collusion) is
fully as much part of the threat model as a CA that issues
certificates without any attempt to verify the identity of the
entity being certified or who colludes in deliberately hiding or
distorting the information.
Now "we" all know that has nothing to do with DNSSEC. It
provides assurance that what is in an authoritative zone and
what reaches the systems closest to the user that actually
validates the signatures and records are the same. But I'm
concerned that it gets oversold to the point that users and
others in the name-using environment hear what we say about "DNS
Security" as "if DNSSEC validates the record, then one has
assurances of the accuracy and integrity of the registrant and
registrant- DNS entry relationship" with "accuracy" and
"integrity" used in their street sense, not the much more narrow
and technical DNS and DNSSEC ones.
Where that loops back to things like DANE is that DANE, at least
apparently, is making assertions about the identity of an
individual or other entity, not [merely] about validation of the
relationship of DNS records as installed/created in comparison
to those received. As with DNSSEC itself, that isn't a problem
if DANE is used carefully and with an understanding of what
assertions are being made and can be trusted. It could be a
significant problem if people over-promise (or over-believe) and
the use of DANE for critical functions becomes widespread enough
to become a tempting target for attacks of technical and/or
social or economic character (just as we have seen on CAs).
There is one sense in which trust models based on DNSSEC that
seem to imply certification of non-DNS entities (like
registrants) are more dangerous than ones based on CA chains.
In the latter case, there are good, and obvious, analogies to
many people's everyday experience. If one finds someone who
claims to be a notary but who operates out of the back of a
taxicab, exhibits no credentials or authorization, who is
willing to certify a document with no more identification of the
signer than the ability to pay a few dollars in cash, and
trusts him to certify signatures on an important document, it is
pretty generally understood what that certification is worth.
We aren't quite there with CAs, but most people are able to at
least understand applicability of the analogy. On the other
hand, when we build a system on top of the DNS and DNSSEC,
relying on elaborate rituals like the signing of the root and
layers of processes that are, for the typical user of the
Internet, indistinguishable from magic, and fail to be clear
that, e.g., no actual certification of registrant identity or
integrity is involved, people may trust the magic rather than
trusting DNSSEC as it is.
That, in turn, could lead to some really nasty surprises --and
loss of confidence in us and the institutions we ask people to
trust-- when the bad effects of that misunderstanding manifest
themselves in a damaging and public attack.
best,
john