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Re: [Doh] Suggestion on draft-ietf-doh-dns-over-https-13: Recommend DANE-TLS to authenticate the TLS-certificate

"Rene 'Renne' Bartsch, B.Sc. Informatics" <ietf@bartschnet.de> Thu, 16 August 2018 15:42 UTC

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From: "Rene 'Renne' Bartsch, B.Sc. Informatics" <ietf@bartschnet.de>
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Subject: Re: [Doh] Suggestion on draft-ietf-doh-dns-over-https-13: Recommend DANE-TLS to authenticate the TLS-certificate
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Am 16.08.2018 um 15:38 schrieb Eric Rescorla:
> 
> 
> On Thu, Aug 16, 2018 at 1:13 AM, Rene 'Renne' Bartsch, B.Sc. Informatics <ietf=40bartschnet.de@dmarc.ietf.org <mailto:ietf=40bartschnet.de@dmarc.ietf.org>> wrote:
> 
>     Hi,
> 
>     as TLS-certificates forged or obtained by devious means have become common in MITM-attacks by intelligence and criminals
>     I suggest to RECOMMEND authentication of the DoH-server TLS-certificate via DANE-TLS (RFC 6698) in section 10 (Security considerations).
> 
> 
> I don't think we should make this change. Much of the value proposition of DoH is that it's straightforward to run on top of existing HTTPS infrastructure, and as a practical matter nearly all of that infrastructure depends on WebPKI certs and does not do DANE. For that reason, this recommendation would be more aspirational than practical.

The problem I see is that e.g. firewall appliances with fake certificates by intermediate certificates can break privacy and manipulate the DNS records.
Without proper authentication of the DoH-server certificate DoH only protects from script-kiddies.


Renne

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