Hi Roman,

Many thanks for your comments. See our answers inline. Please let us know
if they address your concerns.


On Thu, Jan 6, 2022 at 5:31 AM Roman Danyliw via Datatracker <
nore...@ietf.org> wrote:

> Roman Danyliw has entered the following ballot position for
> draft-ietf-alto-cdni-request-routing-alto-18: No Objection
>
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>
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
>
> Thanks to Klaas Wierenga for the SECDIR review.
>
> Thanks for addressing my DISCUSS point
>
> ** Section 8.
>      For authenticity and integrity of ALTO information, an attacker
>       may disguise itself as an ALTO server for a dCDN, and provide
>       false capabilities and footprints to a uCDN using the CDNI
>       Advertisement service.
>
> -- I don’t follow the intent of the first clause.  Why is an _attacker_
> concerned with the authenticity and integrity of the ALTO information?
>

This bullet describes the same risk scenario as the one in Sec 15.1 of
RFC7285.


>
> -- What role can TLS, an associated server certificate (for the dCDN) and
> configured knowledge of this certificate at the uCDN mitigate some of this
> risk?  Shouldn’t the uCDNs only be communicating with a collection of known
> dCDNs with which it has some out-of-band negotiated arrangement?
>

Yes, the uCDNs should only communicate with known dCDNs. But an attacker
can start a man-in-the-middle attack.
About how to configure TLS, does the second last bullet of this section
make it clear?


>
> ** Section 8.
>       For availability of ALTO services, an attacker may conduct service
>       degradation attacks using services defined in this document to
>       disable ALTO services of a network.
>
> Again, operating under the assumption that the dCDN (ALTO Server) would
> only be
> working with a known (prearranged) set of uCDNs and they would have
> authenticated somehow (per the DISCUSS), couldn’t repeated requested be
> rate
> limited and after attribution, filtered to minimize impact?
>

Yes, considering the limited number of authenticated uCDNs, this security
issue may not be that risky.
This bullet just aligns with Sec 15.5 of RFC7285. Do you strongly think we
should remove this one?

Thanks,
Jensen


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