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Does this even matter? If LE only issues 90 day certs there shouldn’t be any certs they’re signing with this CA Cert that are even valid now either way. If so

by atonse 5y ago

Does this even matter? If LE only issues 90 day certs there shouldn’t be any certs they’re signing with this CA Cert that are even valid now either way. If so then it’s yet another testament to their opinionated decision to only issue 90 day certs. (Which I strongly support)

tialaramex 5y ago
Nobody uses roots to sign End Entity certificates. That's been prohibited for years, and it was always a stupid practice even before it was specifically prohibited. But this is about root trust. Ultimately, why should your software trust this certificate, but not trust some random certificate I just made? If your system only trusts a Let's Encrypt certificate because of the DST Root CA X3 which is from like 2000, and then DST Root CA X3 expires, does your system no longer trust those certificates? If you make actual trust decisions, presumably you've made a few new ones since before the war in Afghanistan started and hopefully you trusted ISRG Root X1, from the organisation running Let's Encrypt. It's been around for a few years, you had time. More likely, you let your OS vendor make such decisions, don't worry all major OS vendors trusted ISRG Root X1 years ago. Apple, Microsoft, and (on behalf of the Free Unixes) Mozilla all OK'd this years and years back. But, if your software is a bit long in the tooth and was poorly made back then, that might not help. OpenSSL 1.0.0 was exciting when it happened, but that was a long time ago too and it didn't know how to handle this correctly. Old enough GnuTLS likewise.
- atonse 5y ago
  Right but my point still stands. Even if you look at the trust chain: They would’ve signed intermediate certs along the way. The intermediate certs would’ve had Expirations before this month Certs signed with the intermediates would’ve expired sooner too. They would’ve stopped signing Intermediate certs for this a few years ago. So what’s the actual risk here? Are there certs out there that have this Cert as a root, with expirations past the lifetime of this root cert? How would that have even been allowed?
  - kxrm 5y ago
    The risk is, older devices. Many devices aren't updated anymore, so they won't have newer root certs. You could argue that those users shouldn't be using those devices with the web, but they do.
    - wtetzner 5y ago
      I think they still support a cross-signed root, so hopefully those users will still be OK.
  - tialaramex 5y ago
    > The intermediate certs would’ve had Expirations before this month No. Nobody does that. Why would you do that? I think you're most likely getting muddled because, in common with many people, you've been thinking about the Web PKI as a graph in which certificates are nodes. It isn't. It's a graph in which the nodes are key pairs, and the certificates are labelled, directional edges. You're suggesting that the labels on any one edge ought to be constrained based on all other labels on edges leading toward the node it's from, and that makes no sense, unsurprisingly we don't do that. > They would’ve stopped signing Intermediate certs for this a few years ago. Again, nobody does this. > So what’s the actual risk here? Are there certs out there that have this Cert as a root, with expirations past the lifetime of this root cert? How would that have even been allowed? Imagine somebody loudly insisting that negative integers don't exist. That they can't exit, they just don't make any sense, obviously there can't be a "minus six" what would that even mean? Frustrating right. That's what this is like.
    - tflinton 5y ago
      But doesn’t antose comment still apply? If all the certificates issued by letsencrypts old CA have expired (since they’ve stopped issuing certs for a year, and their certificates only last 3 months) wouldn’t it stand to reason that if a certificate on and old CA have been replaced with a new CA certificate? And it would then stand to reason any devices that aren’t updated would have slowly watched the web degrade already? In other words with letsencrypt there’s no cliff everyone walks off when the root ca expires, it’s more a 90-day descending hill.

by atonse 5y ago

tialaramex 5y ago

Nobody uses roots to sign End Entity certificates. That's been prohibited for years, and it was always a stupid practice even before it was specifically prohibited. But this is about root trust. Ultimately, why should your software trust this certificate, but not trust some random certificate I just made? If your system only trusts a Let's Encrypt certificate because of the DST Root CA X3 which is from like 2000, and then DST Root CA X3 expires, does your system no longer trust those certificates? If you make actual trust decisions, presumably you've made a few new ones since before the war in Afghanistan started and hopefully you trusted ISRG Root X1, from the organisation running Let's Encrypt. It's been around for a few years, you had time. More likely, you let your OS vendor make such decisions, don't worry all major OS vendors trusted ISRG Root X1 years ago. Apple, Microsoft, and (on behalf of the Free Unixes) Mozilla all OK'd this years and years back. But, if your software is a bit long in the tooth and was poorly made back then, that might not help. OpenSSL 1.0.0 was exciting when it happened, but that was a long time ago too and it didn't know how to handle this correctly. Old enough GnuTLS likewise.

atonse 5y ago
Right but my point still stands. Even if you look at the trust chain: They would’ve signed intermediate certs along the way. The intermediate certs would’ve had Expirations before this month Certs signed with the intermediates would’ve expired sooner too. They would’ve stopped signing Intermediate certs for this a few years ago. So what’s the actual risk here? Are there certs out there that have this Cert as a root, with expirations past the lifetime of this root cert? How would that have even been allowed?
- kxrm 5y ago
  The risk is, older devices. Many devices aren't updated anymore, so they won't have newer root certs. You could argue that those users shouldn't be using those devices with the web, but they do.
  - wtetzner 5y ago
    I think they still support a cross-signed root, so hopefully those users will still be OK.
- tialaramex 5y ago
  > The intermediate certs would’ve had Expirations before this month No. Nobody does that. Why would you do that? I think you're most likely getting muddled because, in common with many people, you've been thinking about the Web PKI as a graph in which certificates are nodes. It isn't. It's a graph in which the nodes are key pairs, and the certificates are labelled, directional edges. You're suggesting that the labels on any one edge ought to be constrained based on all other labels on edges leading toward the node it's from, and that makes no sense, unsurprisingly we don't do that. > They would’ve stopped signing Intermediate certs for this a few years ago. Again, nobody does this. > So what’s the actual risk here? Are there certs out there that have this Cert as a root, with expirations past the lifetime of this root cert? How would that have even been allowed? Imagine somebody loudly insisting that negative integers don't exist. That they can't exit, they just don't make any sense, obviously there can't be a "minus six" what would that even mean? Frustrating right. That's what this is like.
  - tflinton 5y ago
    But doesn’t antose comment still apply? If all the certificates issued by letsencrypts old CA have expired (since they’ve stopped issuing certs for a year, and their certificates only last 3 months) wouldn’t it stand to reason that if a certificate on and old CA have been replaced with a new CA certificate? And it would then stand to reason any devices that aren’t updated would have slowly watched the web degrade already? In other words with letsencrypt there’s no cliff everyone walks off when the root ca expires, it’s more a 90-day descending hill.