[NSIS] Pending issue secdir review of draft-ietf-nsis-nslp-natfw-13.txt

[Martin Stiemerling <[e-mail]>]

Hi all,

We still have the pending issue of handling the sec dir review of the  
NATFW NSLP form last December.

My current intention is too follow the guidance and to rework the  
whole security section to get it shorten and focussed on the real  
challenges of the NATFW NSLP.

Any further thoughts or objections?

Thanks,

   Martin (for all NATFW NSLP authors)

Anfang der weitergeleiteten E-Mail:

> Von: Magnus Westerlund <[e-mail]>
> Datum: 11. Dezember 2006 10:22:31 MEZ
> An: NSIS <[e-mail]>
> Kopie: [e-mail]
> Betreff: [NSIS] [Fwd: secdir review of draft-ietf-nsis-nslp- 
> natfw-13.txt]
>
> Hi NSIS
>
> Many thanks to Catherine Meadows (CC) who has done the Security  
> Directorate review attached. It was done on my and the WG chairs  
> request through the security ADs to help check the security details  
> of the document. It contains the normal boilerplate for document  
> that are in IESG review, but as you know this document isn't in  
> that step yet. I hope this can help improve the document.
>
> Cheers
>
> Magnus Westerlund
>
> IETF Transport Area Director & TSVWG Chair
> ----------------------------------------------------------------------
> Multimedia Technologies, Ericsson Research EAB/TVA/A
> ----------------------------------------------------------------------
> Ericsson AB                | Phone [phone]
> Torshamsgatan 23           | Fax   [phone]
> S-164 80 Stockholm, Sweden | mailto: [e-mail]
> ----------------------------------------------------------------------
>
> Von: Catherine Meadows <[e-mail]>
> Datum: 10. Dezember 2006 15:32:45 MEZ
> An: [e-mail], [e-mail], [e-mail],  
> [e-mail], [e-mail],  
> [e-mail]
> Kopie: Catherine Meadows <[e-mail]>
> Betreff: secdir review of draft-ietf-nsis-nslp-natfw-13.txt
>
>
> 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.
>
> This ID describes a protocol by which hosts may signal along the  
> path used
> for transport of data packets the information necessary to configure
> NATs and firewalls
> according to the needs of the
> application data flows.  Not surprisingly, the use of this protocol  
> by unauthorized
> hosts could cause major security problems.  The security  
> considerations considerations section of this document describes  
> the problems in detail,
> and outlines recommendations for solutions.  These are to have
> security mechanisms providing data origin authentication, replay  
> protection, integrity protection, and optional confidentiality  
> protection.  According to this document, uch security
> mechanisms can be provided for neighboring nodes
> by using a mutually authenticated
> transport layer secured connection and by relying on authorization  
> by the
> neighboring NATFW NSLP entities, as well as randomly generated  
> (that is,
> unpredictable) session IDs.
>
> For non-neighboring nodes (presumably, this means nodes that do not  
> share
> a security association) some sort of authorization is still  
> necessary.  The document
> discusses the possibility of using authorization tokens for this,  
> and also provides
> some recommendations for protecting them (e.g. protection against  
> tampering
> and confidentiality to protect against replay).  The document does not
> go into detail about this, apparently because the usage of  
> authorization tokens
> in NPLS is covered in another document (referenced in this ID).
>
> This security strategy looks plausible, but I found the  
> justification for it very hard to follow.  It starts with a number  
> of possible attacks that an unauthorized host could perform using  
> NSLP.  Almost all of these attacks can be prevented by providing  
> authorization (the exceptions are one or two denial of service  
> attacks), and recommendations for authorizations are accordingly  
> provided.   However, there
> are two cases in which such recommendations are lacking.  In one of  
> these
> (5.2.3, data sender behind a firewall), no reason is given for the  
> lack of a recommendation.  In the other (5.8, misuse of unreleased  
> sessions), it is claimed
> that this will be addressed by the NATFW NSLP.  This last confused me;
> isn't that the protocol that this document describes?
>
> The list of attacks appears to have grown up over a period of time  
> as the document went through its various iterations.  In its  
> current form, the list is not very helpful, especially as the end  
> of the security considerations section, in which the actual  
> recommendations are made do not reference them explicitly.   
> Instead, there
> are somewhat vague comments such as
>    Almost all security threats at the
>    NATFW NSLP layer can be prevented by using a mutually authenticated
>    Transport Layer secured connection and by relying on  
> authorization by
>    the neighboring NATFW NSLP entities.
> It would have been helpful for the reader to know what is meant by  
> "almost all"
> without having to go back through the entire list of attacks.
>
> I would suggest that the authors provide a tightened up, condensed  
> account of the
> security threats against NSLP.  There is no need to try to have an  
> exhaustive list
> of attacks; indeed such a list will be of limited use since one can  
> never be certain that all the possibilities can be exhaustive.   
> Instead, it would be more helpful to described classes of threats,  
> with some illustrative examples.
>
> In the final section, where the recommendations for security  
> mechanisms are
> made, you need to be explicit about the types of threats that are  
> addressed.
> In particular,  some characterization of the types of threats that  
> are and are not addressed by authentication and authorization of  
> neighboring nodes needs to be provided,
>
>
> I am wondering if it would not be a good idea to have a separate ID
> describing the security mechanisms that need to be used by this  
> protocol.
> The WG already seems to be halfway there, since they are already  
> working
> on an ID for authentication tokens.
>
> Catherine Meadows
> Head, Formal Methods Section
> Center for High Assurance Computer Systems
> Code 5540
> Naval Research Laboratory
> Washington, DC 20375
> phone: [phone]
> fax: [phone]
>
> _______________________________________________
> nsis mailing list
> [e-mail]
> https://www1.ietf.org/mailman/listinfo/nsis

[e-mail]
NEC Europe Limited | Registered Office: NEC House, 1 Victoria Road,  
London W3 6BL | Registered in England 2832014

_______________________________________________
nsis mailing list
[e-mail]
https://www1.ietf.org/mailman/listinfo/nsis