Re: [Resolverless-dns] Paper on Resolver-less DNS

[Erik Sy <[e-mail]>]

On 8/23/19 14:05, Vittorio Bertola wrote:
>> Il 23 agosto 2019 13:50 Erik Sy <[e-mail]> ha scritto:
>>
>> Do you think the bullet point "There is a risk of rendering a site
>> unusable." does apply to DANE TLSA?
> Sure, but it also applies to normal HTTPS certificates without pinning. How many times did you try to access an HTTPS website and were stopped by the browser, because the certificate was expired and the owner forgot to renew it, or because the certificate was self-signed, even if the site had not been attacked? It happens every day, but it's not a good reason to stop using certificates and validating them properly - it's rather a good reason for the site owner to get a better webmaster. 
>
Chrome establishes trust in a certificate if it is issued by a valid CA
and included in the Certificate Transparency (CT) logs. Here, the CT
allows to monitor the certificates issued by the CAs. In this ecosystem,
it is unlikely that valid CAs issue illegitimate certificates because
the trust in misbehaving CAs can be revoked at any time.

Additional pinning of certificates provides the benefit that an
illegitimate certificate can be detected during the server
authentication. Note, that CT can detect this only in the aftermath. As
a drawback of pinning, a misconfiguration of this mechanism always leads
to a fatal error. The trade-off at hand is catching misbehaving CAs
before the connection establishment and accepting hard failures due to
possible misconfiguration versus catching the malicious CA only in the
aftermath of the connection establishment. I think that Chrome decided
for the latter one.

Erik