Re: [secdir] Secdir review of draft-ietf-mpls-ldp-gtsm-07
Carlos Pignataro <cpignata@cisco.com> Sat, 02 June 2012 16:23 UTC
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From: Carlos Pignataro <cpignata@cisco.com>
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Date: Sat, 02 Jun 2012 12:23:37 -0400
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To: Brian Weis <bew@cisco.com>
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Cc: secdir@ietf.org, draft-ietf-mpls-ldp-gtsm.all@tools.ietf.org, The IESG <iesg@ietf.org>, "Rajiv Asati (rajiva)" <rajiva@cisco.com>
Subject: Re: [secdir] Secdir review of draft-ietf-mpls-ldp-gtsm-07
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Hi Brian, Many thanks for your review. The document already talks about these two cases, and also already discusses that multi-hop is out of scope; however I agree with you that highlighting this in the Security Considerations adds to completeness, and also like Rajiv's text. I just posted a new rev that I believe addresses these (basically Rajiv's text modulo minor edits). Thanks! -- Carlos. On Jun 1, 2012, at 5:11 PM, Brian Weis wrote: > Hi Rajiv, > > Your proposed text looks good to me. I think it's good to go with this added. > > Thanks, > Brian > > > On Jun 1, 2012, at 1:37 PM, Rajiv Asati (rajiva) wrote: > >> Hi Brian, >> >> Really appreciate your critical review and suggestions. >> >> I agree to your both of your suggestions, and would propose the >> following text for us to include in the next revision. >> >> >> // >> As discussed in section 3, it is possible that >> - GTSM for LDP may not always be enforced on a single-hop LDP peering >> session and may still be susceptible to forged/spoofed protocol packets, >> if the single-hop LDP peering session is set up using Extended >> Discovery. >> - GTSM for LDP may cause LDP peering session to not get established (or >> torn down), if IP routing ever declares that the directly connected peer >> is more than one hop away. >> Suffice to say, use of cryptographic integrity (e.g., RFC 5925) is >> recommended as an alternate solution for detecting forged protocol >> packets (especially for the multi-hop case). >> // >> >> Cheers, >> Rajiv >> >> >>> -----Original Message----- >>> From: Brian Weis (bew) >>> Sent: Friday, June 01, 2012 2:16 PM >>> To: secdir@ietf.org; The IESG >>> Cc: draft-ietf-mpls-ldp-gtsm.all@tools.ietf.org >>> Subject: Secdir review of draft-ietf-mpls-ldp-gtsm-07 >>> >>> 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 document applies the Generalized TTL Security Mechanism (GTSM) >>> mechanism defined in RFC 5082. This mechanism is used by routing >>> protocols as a low-cost non-cryptographic method intended to frustrate >> off- >>> path attackers. It is applicable when the peer is known to be >> connected by a >>> single hop. >>> >>> The security considerations of this draft mostly point to RFC 5082's >>> extensive security considerations section, which is appropriate. >> However >>> because this I-D discusses multi-hop cases in greater detail it would >> be >>> appropriate for the security considerations section to also discuss >> multi-hop >>> a bit more. Here are some thoughts for that: >>> >>> 1) Use of cryptographic integrity (e.g., RFC 5925) should be >> recommended as >>> an alternate solution for detecting forged protocol packets in the >> multi-hop >>> case. >>> >>> 2) GTSM is expected to be enabled by default for Basic Discovery >> because >>> it's usually a single-hop, and disabled for Extended Discovery because >> it's >>> usually multi-hop. But then Section 3 mentions several exceptions, >> which >>> apparently need to be administratively configured away from the >> defaults. >>> Failing to do this when needed results in security risks in either >> case: either >>> GTSM isn't deployed when it should be and the router is inadvertently >> open >>> to spoofing, or GTSM is deployed when it shouldn't be and this results >> in an >>> availability issue because LDP packets will be dropped before reaching >> the >>> LDP peer. This should be stated in the Security Considerations. >>> >>> Brian >>> >>> >>> >>> >>> >> > > > -- > Brian Weis > Security Standards and Technology, SRTG, Cisco Systems > Telephone: +1 408 526 4796 > Email: bew@cisco.com > > > > >
- [secdir] Secdir review of draft-ietf-mpls-ldp-gts… Brian Weis
- Re: [secdir] Secdir review of draft-ietf-mpls-ldp… Brian Weis
- Re: [secdir] Secdir review of draft-ietf-mpls-ldp… Rajiv Asati (rajiva)
- Re: [secdir] Secdir review of draft-ietf-mpls-ldp… Rajiv Asati (rajiva)
- Re: [secdir] Secdir review of draft-ietf-mpls-ldp… Carlos Pignataro