[dns-operations] summary of recent vulnerabilities in DNS security.

[Haya Shulman]

IMHO, DNSSEC is simply the natural defense against the attacks, which
is why I did not explicitly mention it, but I definitely had it in
mind :-)

Regarding the proxy-behind-upstream: to prevent the attacks DNSSEC has
to be deployed(and validated) on the proxy. Currently it seems that
there are proxies that signal support of DNSSEC (via the DO bit), but
do not validate responses, and validation is typically performed by
the upstream forwarder.

---

The complete absense of any mention of DNSSEC among those recommendations



(or elsewhere) reads like an implicit claim that DNSSEC would not
help.  Even if that claim was not intended, would it be accurate?

Would DNSSEC make any of recommendations less necessary or perhaps
even moot?  If DNSSEC by itself would be effective against cache
poisoning, then isn't it among the recommendations, especially for
"Resolver-behind-Upstream"?  Why aren't efforts to protect port
randomization, hide hidden servers and so forth like trying to make
it safe to use .rhosts and /etc/hosts.equiv files by filtering ICMP
dedirects and IP source routing, and strengthening TCP initial sequence
>
> numbers?



On Sat, Oct 19, 2013 at 6:53 PM, Haya Shulman <haya.shulman at gmail.com>wrote:

> This is correct, the conclusion from our results (and mentioned in all our
> papers on DNS security) is to deploy DNSSEC (fully and correctly). We are
> proponents of cryptographic defenses, and I think that DNSSEC is the most
> suitable (proposed and standardised) mechanism to protect DNS against cache
> poisoning. Deployment of new Internet mechanisms is always challenging (and
> the same applies to DNSSEC). Therefore, we recommend short term
> countermeasures (against vulnerabilities that we found) and also
> investigate mechanisms to facilitate deployment of DNSSEC.
>
>
> On Sat, Oct 19, 2013 at 6:05 PM, Phil Regnauld <regnauld at nsrc.org> wrote:
>
>> P Vixie (paul) writes:
>> > M. Shulman, your summary does not list dnssec as a solution to any of
>> these vulnerabilities, can you explain why not? Vixie
>>
>>         I was wondering about that, and went to look at the abstracts:
>>
>> http://link.springer.com/chapter/10.1007/978-3-642-33167-1_16
>>
>> "Security of Patched DNS"
>>
>> [...]
>>
>> We present countermeasures preventing our attacks; however, we believe
>> that our attacks provide additional motivation for adoption of DNSSEC
>> (or other MitM-secure defenses).
>>
>>         So at least this seems to be mentioned in the papers themselves
>> (Id
>>         didn't pay to find out).
>>
>>         But I agree that the summary would benefit from stating this, as
>> it's
>>         currently only way to to avoid poisoning. Not stating it could
>> lead
>>         some to believe that these attacks are immune to DNSSEC
>> protection of
>>         the cache.
>>
>>         Cheers,
>>         Phil
>>
>
>
>
> --
>
> Haya Shulman
>
> Technische Universität Darmstadt****
>
> FB Informatik/EC SPRIDE****
>
> Morewegstr. 30****
>
> 64293 Darmstadt****
>
> Tel. +49 6151 16-75540****
>
> www.ec-spride.de
>



-- 

Haya Shulman

Technische Universität Darmstadt****

FB Informatik/EC SPRIDE****

Morewegstr. 30****

64293 Darmstadt****

Tel. +49 6151 16-75540****

www.ec-spride.de
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