Hi Mike, On Thu, Aug 3, 2017 at 10:47 PM, Michael StJohns <m...@nthpermutation.com> wrote:
> On 8/3/2017 3:01 PM, Aanchal Malhotra wrote: > > A DNSKEY RRset with pre-published KSK is signed by the old (now > compromised) KSK. When the resolver uses RFC 5011 for the trust anchor > update, the attacker can inject a new KSK (signed by the compromised KSK). > Which KSK is now the new T*rust Anchor *for the resolver? > > The resolver trust point trust anchor set contains both the old and > pre-published stand-by key. When the old KSK is compromised, you set the > revoke bit on the old KSK, and sign the DNSKEY RRSet with both the revoked > KSK and the standby KSK. The stand by key does not trace its trust > through the old key except during the process of being added. The attempt > to inject the new KSK is foiled by revoking the old KSK and publishing the > revocation before the hold-down time expires for the resolver(s). > I understand and agree to what you say. And even RFC 5011 explicitly states that this approach works only if there is a backup/standby/pre-published (whatever name we like) and the assumption that both active and stand-by keys are not compromised at the same time. The point is again, as Warren mentioned, that one needs two trust anchors in this case. And the issues ensue.... Also, I am not sure if there is any implementations that are actually doing standby-keys (not that I am aware of). What I am trying to say is that we do not have a solution to this problem without a back-up key set? > > At some point - ideally quickly after the old KSK revocation - you publish > a new standby KSK long enough to inject it as a new trust anchor. > > Mike > > > > _______________________________________________ > DNSOP mailing list > DNSOP@ietf.org > https://www.ietf.org/mailman/listinfo/dnsop > >
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