Re: [quicwg/base-drafts] Fix for off-path migration attack (#2033)

Kazuho Oku <notifications@github.com> Thu, 22 November 2018 06:24 UTC

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Subject: Re: [quicwg/base-drafts] Fix for off-path migration attack (#2033)
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kazuho commented on this pull request.



> +path.
+
+An endpoint that receives a PATH_CHALLENGE on an active path SHOULD send a
+non-probing packet in response.  If the non-probing packet arrives before any
+copy made by an attacker, this results in the connection being migrated back to
+the original path.  Any subsequent migration to another path resets this entire
+process.
+
+Abandoning this validation attempt before it either succeeds or times out
+increases exposure to the packet copying attack.
+
+This defense is imperfect, but this is not considered a serious problem. If the
+path via the attack is reliably faster than the original path despite multiple
+attempts to use that original path, it is not possible to distinguish between
+attack and an improvement in routing.
+

Yeah but doesn't the connection simply move back to the original path once the attacker stops racing the packets?

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