Subject: [alto] Roman Danyliw's No Objection on draft-ietf-alto-cdni-request-routing-alto-18: (with COMMENT)

From: Roman Danyliw via Datatracker <[email-masked]>
Date: Wed, 05 Jan 2022 13:30:50 -0800

Roman Danyliw has entered the following ballot position for
draft-ietf-alto-cdni-request-routing-alto-18: No Objection

When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)

Please refer to https://www.ietf.org/blog/handling-iesg-ballot-positions/
for more information about how to handle DISCUSS and COMMENT positions.

The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-alto-cdni-request-routing-alto/

----------------------------------------------------------------------
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?

-- 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?

** 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?

---

From: Jensen Zhang <[email-masked]>
Date: Tue, 18 Jan 2022 22:00:05 +0800

Hi Roman,

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

> https://datatracker.ietf.org/doc/draft-ietf-alto-cdni-request-routing-alto/

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

> 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?

> 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

>
>
>
> _______________________________________________
> alto mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/alto
>