At 3:04 PM +0200 3/29/12, Shane Amante wrote:
Steve,

Thanks for the response. First, a high-level comment before more specific responses below.

Shane, sorry to be so late in replying. I think you and Andrew have already discussed a number of the issues you raised below, so I'll just make a few, brief comments.

First, as Sriram noted, BGPSEC carries only the secure AS path info, not the old As path attribute. So there cannot be a mismatch between the two, and loop detection should work. Because of the signature requirements, no bogus ASN's can appear in the secured path, no hops can be stripped, etc. It's an implementation decision as to whether a router checks the secured path data before validating the sigs to detect a loop. One might do this to avoid wasting cycles on crypto.

...
There is text about MITM threat in Section 4.2; however, that seems to relate to crypto security between two adjacent routers over, say, a directly connected link. However, what about MITM attacks that create what appear to be valid BGPSEC_Path_Signature attribute that would pass verification by downstream parties?

I still do not understand. Unless a MITM has access to the private keys for the BGP routers in question, it cannot generate sigs that will validate when checked by downstream parties.'

Steve
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