Re: [Sidrops] what to do when the CRL is hosed?

[Stephen Kent <[e-mail]>]

Job,
> On Tue, Mar 24, 2020 at 03:20:09PM +0100, Martin Hoffmann wrote:
>> Job Snijders wrote:
>>> I'm not sure I agree - routinator, fort and octorpki are trivially
>>> forced to use rsync if the attacker blocks TCP port 443.
>> At least Routinator does not fall back to rsync once it has
>> successfully completed accessing the repository via RRDP once. I am
>> open to strengthen this to not ever use rsync if there is a RRDP URI
>> in the certificate.
> I'm interpreting the willingness to attempt to make MITM attack slightly
> harder as an indicator that the described MITM partial
> withholding/corruption attack scenarios are valid and problematic. :-)
>
> I don't think a conclusion about the integrity of the DELTA snapshot can
> be derived from the fetch mechanism itself: just because it was
> retrieved over HTTPS doesn't mean there was no MITM attack. The
> diginotar situation comes to mind, and crazier things have existed in
> the wild.

Use of TLS, absent a CA compromise, protects against MITM attacks.

The CA compromise you cited (DigiNotar) was serious because of the Web 
PKI model, in which any trust anchor can issue a cert for any EE. Today, 
with the use of cert pinning and cert transparency logs, the likelihood 
of such attacks has very dramatically decreased in the Web PKI environment.

Can you provide an example of one of the "crazier things" (relevant to 
TLS and the Web PKI) hat have happened in the wild, and which are 
applicable here?

Steve