Subject: [secdir] secdir review of draft-ietf-isis-sbfd-discriminator-02

From: Tom Yu <[email-masked]>
Date: Tue, 17 Nov 2015 22:06:19 -0500

I have reviewed this document as part of the security directorate's 
ongoing 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 them
   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
someone 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

---

From: "Les Ginsberg (ginsberg)" <[email-masked]>
Date: Wed, 18 Nov 2015 04:31:53 +0000

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 [mailto:[email-masked]]
> Sent: Tuesday, November 17, 2015 7:06 PM
> To: [email-masked]; [email-masked]; draft-ietf-isis-sbfd-
> [email-masked]
> Subject: secdir review of draft-ietf-isis-sbfd-discriminator-02
> 
> I have reviewed this document as part of the security directorate's ongoing
> 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
> 
> 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 someone
> impersonates the responder, but not one where someone impersonates an
> initiator.
> 
> explicitly.  I'm not sure whether it's best to leave things alone, revise this
> document, or revise [S-BFD].
> 
> -Tom

---

From: Tom Yu <[email-masked]>
Date: Wed, 18 Nov 2015 14:28:01 -0500

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.