Subject: Re: [DNSOP] DNS privacy, recursive-to-authoritative

From: Jacob Appelbaum <[email-masked]>
Date: Thu, 3 Sep 2015 07:22:31 +0000

On 9/2/15, Paul Vixie <[email-masked]> wrote:
>
>
> John R Levine wrote:
>> ...
>>
>> Tor is one approach to query security that seems to work pretty well
>> give or take side channel leakage.  Dunno if there are any others, but
>> it is clearly a very hard problem, and not one we're going to solve
>> any time soon.
>
> i think we have to be realistic. the national security apparatus of the
> largest dozen economies have effectively unlimited resources. they will
> spend as many of our tax dollars as it takes to buy as much equipment
> and talent and methodology and electric power as it takes to watch what
> they decide is important to watch.

What of the national security apparatus of the rest of the countries
of the world? Or the criminal cops buying HackingTeam software? Or
perhaps a teenager with tcpdump?

Until the invention of quantum computers, we can protect data from
being instantly available to most of these groups most of the time.
Right now, we're not doing any such thing and in fact it is the
opposite: we're failing to protect data from all of these groups, all
of the time.

I do agree though - we have to watch out for people that they try to
buy. There is easy no technical solution to dealing with people who
stop protections from being deployed. We know the NSA sends people to
the IETF and specifically to make protocols easier to intercept and
exploit. One might guess that other services do similar things. How
might we find such people? How might we ensure that they stop harming
users? I think we won't and so rather we should finding flaws which
benefit such an adversary and fix them.

>
> i'm all for PFS on the cache miss path

Could you identify all of the parties involved, what they do and which
ones in your view should have privacy? It sounds like you want to
support certain kinds of end user privacy. I'm extremely curious to
hear a specific proposal of who deserves and who doesn't deserve
privacy.

My outline is as follows: everyone and every system should have
security and privacy in the form of forward-secret authenticated
cryptography, all of the time, enabled by default.

Ideally we should design the link level protocols to look identical
and to ensure that selector based surveillance is ineffective for any
data relating to DNS inside of the encrypted protocol. Thus I expect a
sniffer may see that it is encrypted DNS traffic but will be limited
to that as an XKeyscore AppID. The others selectors available will be
IP, port and other metadata leaked by the TCP/IP protocol itself.

> but trying to hide who the query
> came from so that an authority server has less insight, is nutball
> stuff.

I disagree and strongly. We need protocols that compose with other
protocols. This needs to be one of the design goals. It won't happen
over night. I already have this property when I use Tor with some
other software - shouldn't everyone else have it too?

> remember that the NSA (et al) is a form of "us" and that we will
> not stop "us" with math. real change there will come in the voting booth.

With the utmost respect, I believe your theory of change lacks
evidence and flies in the face of what we've seen in practice. We've
found that the math is the main thing that changes the economics of
mass surveillance. Power, space and cooling are the other major
factors. Agencies that tap fiber already *break* laws or the laws are
written to ensure that non-US persons aren't considered as people.

While I support a limited view of your theory of change in small
pockets of the world, I believe that no matter how you or I vote - the
fact remains: the BND, the PLA or the FSB won't care about your or my
American vote, likewise with nearly every other country in the world
we'll get what technology ensures for us.

We need to step up our game and the zeroth step is to recognize that
we need to change the technical and the political situation at the
same time. Deploying forward secret tech is what is currently lacking
for most protocols. In DNS the situation is worse. There is political
will in many countries around the world but change stops when the
technology isn't up to the task.

Pervasive monitoring as discussed in RFC 7258 is an attack. DNS
currently fails on a technical level to address this kind of attack.

All the best,
Jacob

---

From: "John R Levine" <[email-masked]>
Date: 3 Sep 2015 10:21:05 -0400

> being instantly available to most of these groups most of the time.

Aw, come on.  There are root servers in China.

> cryptography, all of the time, enabled by default.

That's nice, but this is the IETF.  We can't even get people to stop 
running BIND 4.

Regards,
John Levine, [email-masked], Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail.

---

From: Jacob Appelbaum <[email-masked]>
Date: Thu, 3 Sep 2015 15:31:35 +0000

> Aw, come on.  There are root servers in China.

I'm much more worried about the root servers run by people who also
deploy drones for assassination, thanks. Though in the end, I'm
concerned about those servers and all the network links too.

With query minimization and link level encryption, we'll still have to
deal with operators that will behave badly. That is yet another
problem to tackle and important! DNSSEC solves many of the bad
behaving operator issues but not issues of confidentiality. I guess
there are some things we can to show that a root server is misusing
otherwise unpublished information with some kind of honeytoken.

With query privacy, link level encryption, query minimization and so
on, I think there would be a massive step forward in the security of
the DNS. Right now - we don't need to be seriously concerned with
where a root server is in terms of the violation of privacy - almost
all of the networks of the world are monitored by *someone* at the
moment.

> That's nice, but this is the IETF.  We can't even get people to stop

Not with that attitude, obviously!

The IETF is able to make strong privacy respecting standards that
protect users and operators alike. The anti-privacy obstructionism
attitude from some in the IETF is pretty frustrating. This negative
attitude stalls classification of problems as well as standardization
of positive changes and it causes a lot of needless infighting.

Mass surveillance is a problem and what I said seems a reasonable
goal. I'm open to counter proposals and the same question I asked
Vixie is really for everyone or anyone at all.

Even though we won't achieve it overnight, once we figure out what to
do - it is possible to solve it for anyone willing to deploy those
solutions. We might even get those people running BIND (4!?) to
upgrade!

All the best,
Jacob