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

Job Snijders <> Wed, 26 February 2020 17:39 UTC

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Date: Wed, 26 Feb 2020 17:39:35 +0000
From: Job Snijders <>
To: Stephen Kent <>
Cc: Tim Bruijnzeels <>,
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Subject: Re: [Sidrops] what to do when the CRL is hosed?
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On Wed, Feb 26, 2020 at 12:03:33PM -0500, Stephen Kent wrote:
> As for the considerable leeway accorded to RPs in the Manifest document, I
> concur that it allows inconsistent local behavior. If the WG can agree on
> more proscriptive language, that would be good. When we wrote 6486 we were
> unable to agree on such, as we tried to balance robustness vs. responses to
> possible active attacks on repositories or communications between an RP and
> a repository.

Imagine a scenario where a money-in-the-middle (sic) strategically hides
a select few ROAs, example:

MITM shows rsync://
( AS 0 - expires July 1st, 2021)

but hides rsync://
( AS 3320 - expires July 1st, 2021)

If Origin Validating EBGP edge routers ends up honoring only a *subset*
of VRPs, it may result in catastrophic hard-to-troubleshoot outages. In
this example, the victim end up being unable to reach half of Germany.

I think the entire repository should be considered invalid if a single
file is missing but was referenced in the manifest. One can't produce
rules based upon false or incomplete data, and one can't protect against
hijacks using unsigned data.

expired CRL? repository invalid
any file missing that was referenced in manifest? repository invalid
the above also means, is the CRL missing? repository invalid
in addition to any cert being expired? underlaying objects invalid

Any other behaviour is a security problem, unsafe. Leeway does more
damage than good.

I believe the premise for Origin Validation to work on the Internet it
is that in order to get it deployed, BGP has to 'fail open', but in the
RPKI cache validation process one must 'fail close', which depends on
all validators being 'strict'. If the RPKI component doesn't fail
closed, it produces false filters, which goes against our desire for BGP
to be able to 'fail open'.

Kind regards,