Re: [secdir] Secdir review of draft-ietf-mpls-ldp-gtsm-07
Brian Weis <bew@cisco.com> Fri, 01 June 2012 21:11 UTC
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From: Brian Weis <bew@cisco.com>
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Date: Fri, 01 Jun 2012 14:11:01 -0700
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To: "Rajiv Asati (rajiva)" <rajiva@cisco.com>
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Cc: draft-ietf-mpls-ldp-gtsm.all@tools.ietf.org, The IESG <iesg@ietf.org>, secdir@ietf.org
Subject: Re: [secdir] Secdir review of draft-ietf-mpls-ldp-gtsm-07
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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