Re: [secdir] [v6ops] Secdir last call review of draft-ietf-v6ops-transition-ipv4aas-11

Christian,

As mentioned by Jordi, RFC8026 already describes the attack vector you mentioned. 

Wouldn't pointing to https://tools.ietf.org/html/rfc8415#section-22 be sufficient here? 

Cheers,
Med

> -----Message d'origine-----
> De : ietf [mailto:ietf-bounces@ietf.org] De la part de Christian Huitema
> Envoyé : vendredi 14 décembre 2018 08:26
> À : JORDI PALET MARTINEZ; secdir@ietf.org
> Cc : v6ops@ietf.org; ietf@ietf.org; draft-ietf-v6ops-transition-
> ipv4aas.all@ietf.org
> Objet : Re: [v6ops] Secdir last call review of draft-ietf-v6ops-transition-
> ipv4aas-11
> 
> 
> On 12/13/2018 2:09 PM, JORDI PALET MARTINEZ wrote:
> > Hi Christian,
> >
> > Thanks a lot for your review.
> >
> > Please see below in-line.
> >
> > I'm working in a new version according to the comments got from the ops
> review as well, so will be able to integrate yours very quickly.
> >
> > Regards,
> > Jordi
> >
> >
> >
> > -----Mensaje original-----
> > De: v6ops <v6ops-bounces@ietf.org> en nombre de Christian Huitema
> <huitema@huitema.net>
> > Fecha: jueves, 13 de diciembre de 2018, 21:50
> > Para: <secdir@ietf.org>
> > CC: <v6ops@ietf.org>, <ietf@ietf.org>, <draft-ietf-v6ops-transition-
> ipv4aas.all@ietf.org>
> > Asunto: [v6ops] Secdir last call review of draft-ietf-v6ops-transition-
> ipv4aas-11
> >
> >     Reviewer: Christian Huitema
> >     Review result: Has Issues
> >
> >     I have reviewed draft-ietf-v6ops-transition-ipv4aas-11 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.
> >
> >     The summary of the review is "ready with issue".
> >
> >     The document describes solution for providing "IPv4 as a service", i.e.
> >     provision of IPv4 as a service over an IPv6 only network.
> >     It calls this support "transition as a service".
> >
> >     For various reasons, IETF working groups have standardized not just one
> but
> >     five different mechanisms for providing this transition: 464XLAT
> [RFC6877],
> >     Dual-Stack Lite [RFC6333], Lightweight 4over6 (lw4o6) [RFC7596],
> >     MAP-E [RFC7597], and MAP-T [RFC7599]. (I am sure that Monty Python
> could have
> >     produced a nice sketch about that.) The purpose of the draft is to
> >     state how home routers (a.k.a. customer premise equipment, CPE) should
> >     inform local devices about which of the mechanisms are available, which
> >     should be preferred, and what parameters should be used when deploying
> >     the chosen services. This is done using the DHCPv6 "S46" option
> >     specified in RFC 8026.
> >
> >     The draft also makes specific recommendation regarding the use of the
> UPnP and
> >     PCP services, by requiring specific error codes when a requested port
> mapping
> >     is not available through the specified transition technology.
> >
> >     The security section briefly points to the "Basic Requirements for IPv6
> >     Customer Edge Routers" specified in RFC 7084, and to the security
> >     section of each of the RFC describing the security technologies, and
> implicitly
> >     argues that there are no other security issues. I think that is
> insufficient.
> >
> >     The draft introduces a reliance on the DHCPv6 "S46" option for
> assessing the
> >     relative priority of different transition technologies. An attacker
> could spoof
> >     the DHCPv6 response, and direct client traffic to a different
> technology than
> >     selected by the service provider. This could be used, for example, to
> capture
> >     IPv4 traffic in an IPv6 network and send it to a route chosen by the
> attacker.
> >     The attack might also be used in a dual stack network that does not
> support
> >     any transition technology. I don't understand how this attack is
> mitigated.
> >
> > Not sure if you will suggest here that we should say something about the
> security considerations already mention in RFC8026. In general all those are
> generic DHCPv6 security considerations I think.
> 
> Basically, the devices should be programmed to ignore DHCPv6 if they
> have another more secure way of getting their configuration data. Plus,
> apply general defense against DHCPv6 hacks in the network, etc. I
> understand that your draft is meant to inform the building of CPEs, but
> its effect is generalization of an unsafe mechanism.
> 
> 
> >
> >     Nits:
> >
> >     The introduction uses the acronym WAN without spelling out "Wide Area
> Network".
> >     Also, WAN is used as substitute for local Internet Service Provider
> network. We could
> >     debate whether such networks are always "wide area", by opposition to
> say
> >     "metropolitan" or "regional". This is the same convention used in RFC
> 7084 that
> >     this document updates. It is arguably defined by reference, but
> spelling it out
> >     would be nice.
> >
> > Will do.
> >
> >
> >     The comparison with RFC7084 section includes a mangled sentence:
> >
> >        This document doesn't include support for 6rd ([RFC5969]), because
> as
> >        in an IPv6-in-IPv4 tunneling.
> >
> > Typo, sorry the correct sentence was:
> >        This document doesn't include support for 6rd ([RFC5969]), because
> is
> >        an IPv6-in-IPv4 tunneling.
> 
>        This document doesn't include support for 6rd ([RFC5969]), because it
> is
>        an IPv6-in-IPv4 tunneling.
> 
> >
> >     Please rephrase. Please also rephrase the next sentence, for similar
> reasons:
> >
> >        Regarding DS-LITE [RFC6333], this document includes slightly
> >        different requirements, because the PCP ([RFC6887]) support and the
> >        prioritization of the transition mechanisms, including dual-stack.
> >
> > I think it is much clear this way:
> >
> >        Regarding DS-LITE [RFC6333], this document includes slightly
> >        different requirements, related to the support of PCP ([RFC6887]),
> >        IGD-PCP IWF [RFC6970] and the prioritization of the transition
> >        mechanisms, including dual-stack.
> 
> OK.
> 
> 
> >
> >
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> >     https://www.ietf.org/mailman/listinfo/v6ops
> >
> >
> >
> >
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