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The point of rotation for these kinds of keys is that it limits the blast radius of what happens if an employee compromises such a key. This is sort of like how there are one or two die-hard PGP advocates who have come up with a whole Cinematic Universe where authenticated encryption is problematic ("it breaks error recovery! it's usually not what you want!") because mainstream PGP doesn't do it. Except here, it's that key rotation is bad, because of how often DNSSEC has failed to successfully pull off coordinated key rotations.

by cyberax8 hours ago|

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I can see the periodic rotations used as a way to keep up the operational experience. This is indeed a valid reason, although it needs to be weighted against the increased risk of compromise due to the rotation procedure itself.

I'm just saying that rotating the key just in case someone compromised it is not a great idea. Doubly so if it's done infrequently enough for the operational experience to atrophy between rotations.

And yeah, I fully agree that anything surrounding the DNSSEC operations is a burning trash fire. It doesn't have to be this way, but it is.

by tptacek8 hours ago|

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I'm glad we agree about DNSSEC, but the rationale I'm giving you for key rotation is the same reason we use short-lived secrets everywhere in modern cryptosystems. It's not controversial (except among Unix systems administrators).

by cyberax7 hours ago|

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Oh, I never disagreed about the state of DNSSEC. It's horrible. Along with the rest of the DNS infrastructure (I just had the reason to remember the DNS haiku again today, unrelated to .de). My disagreement is that I believe that DNSSEC should be fixed, rather than abandoned. And I believe that this does not actually require all that much work.

And I just don't fully buy this rationale for asymmetric key rotation. It makes total sense for symmetric secrets (except for passwords).

by jcgl3 hours ago|

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> Nope. Key material rotation is just circus when it's done for the sake of rotation.

I'm a mere sysadmin and not a cybersecurity expert. But this is always something that leaves me torn.

On the one hand, yes, rotation periods for many/most credentials are long enough that you're not really de-risking yourself all that much.

On the other hand, doing regular rotations allows you to tighten up your threat model. A regularly-rotated credential allows you to say "I implicitly trust that this credential has not been compromised prior to the previous rotation."[0] Whereas, without credential rotation, you're saying "I implicitly trust that this credential has not been compromised ever."

The latter to me seems clearly like the inferior model. The question is just whether the cost-benefit pencils out. And that is obviously very situationally dependent. That calculus doesn't pencil out when dealing with user-owned passwords for instance (i.e. the costs of regular password rotation dominate the benefits of the improved threat model). Human limitations with memory and such are the main issue there. However, that doesn't apply to e.g. hypothetical sufficiently developed DNSSEC infrastructure. Does that calculus pencil out there? I don't know. But it seems plausible at least.

[0] Modulo attackers having been able to pivot into a persistent threat with a previously-compromised credential.

by Avamander3 hours ago|

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> Or maybe an employee has compromised the new key that is going to be rotated in, while the old key is securely rooted in an HSM?

Also possible, but that'd be an active threat that has some probability of being caught.

Never replacing keys allows permanent compromise that can only be caught if someone directly observes misuse.

Though nobody monitors DNSSEC like that, nor uses it, so it's fine from that aspect I guess.