Re: [secdir] secdir review of draft-ietf-isis-sbfd-discriminator-02 (draft-ietf-bfd-seamless-base)

"Alvaro Retana (aretana)" <> Thu, 19 November 2015 22:18 UTC

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From: "Alvaro Retana (aretana)" <>
To: Tom Yu <>, "" <>
Thread-Topic: secdir review of draft-ietf-isis-sbfd-discriminator-02 (draft-ietf-bfd-seamless-base)
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Date: Thu, 19 Nov 2015 22:18:11 +0000
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Cc: "Les Ginsberg \(ginsberg\)" <>, "" <>, "" <>, "" <>, "" <>
Subject: Re: [secdir] secdir review of draft-ietf-isis-sbfd-discriminator-02 (draft-ietf-bfd-seamless-base)
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I'm cc'ing the authors of draft-ietf-bfd-seamless-base on this thread so
that your comments can be considered as they update the document.



On 11/18/15, 2:28 PM, "Tom Yu" <> wrote:

>Given that S-BFD is still in AD Evaluation, it seems that there is still
>an opportunity to update the S-BFD Security Considerations, so that the
>IS-IS draft will no longer point to apparently absent text in the S-BFD
>Security Considerations.
>"Les Ginsberg (ginsberg)" <> writes:
>> Tom -
>> Thanx for the review.
>> If you are not happy with the Security section of the base S-BFD draft
>>it seems to me it makes the most sense to address any issues in that
>>document. Trying to make up for any shortcomings in S-BFD draft by
>>adding to  the IGP drafts (there is a similar OSPF S-BFD draft) when the
>>IGPs are merely acting as a transport for opaque information (as you
>>say) does not seem appropriate to me.
>> Can we close on this issue?
>>    Les
>>> -----Original Message-----
>>> From: Tom Yu []
>>> Sent: Tuesday, November 17, 2015 7:06 PM
>>> To:;; draft-ietf-isis-sbfd-
>>> Subject: secdir review of draft-ietf-isis-sbfd-discriminator-02
>>> I have reviewed this document as part of the security directorate's
>>> effort to review all IETF documents being processed by the IESG.  These
>>> comments were written primarily for the benefit of the security area
>>> directors.  Document editors and WG chairs should treat these comments
>>> just like any other last call comments.
>>> Summary: ready with nits
>>> I agree with the first paragraph of the Security Considerations, in
>>>that I think
>>> it's unlikely that this document introduces security risks for IS-IS,
>>>which as I
>>> understand it, effectively transports the proposed S-BFD
>>>discriminators as an
>>> uninterpreted opaque payload.
>>> The second paragraph
>>>    Advertisement of the S-BFD discriminators does make it possible for
>>>    attackers to initiate S-BFD sessions using the advertised
>>>    information.  The vulnerabilities this poses and how to mitigate
>>>    are discussed in the Security Considerations section of [S-BFD].
>>> refers to the Security Considerations of the [S-BFD] base document.
>>>The [S-
>>> BFD] Security Considerations describe some strengthening practices, but
>>> doesn't seem to describe the vulnerabilities in significant detail.
>>> [S-BFD] Security Considerations seems to describe an attack where
>>> impersonates the responder, but not one where someone impersonates an
>>> initiator.
>>> Other sections of [S-BFD] might imply the existence of this sort of
>>> vulnerability, but the Security considerations seems not to mention it
>>> explicitly.  I'm not sure whether it's best to leave things alone,
>>>revise this
>>> document, or revise [S-BFD].
>>> -Tom