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> The surprising aspect is that Authz has a validity of 300 days (which is likely to be increased) This is not true. Authorization lifetimes are only going to

by veeti 10y ago

> The surprising aspect is that Authz has a validity of 300 days (which is likely to be increased) This is not true. Authorization lifetimes are only going to get shorter and shorter [1], and have already been reduced to 90 days. [1] https://community.letsencrypt.org/t/upcoming-api-changes/17947 https://community.letsencrypt.org/t/upcoming-api-changes/179...

dc352 10y ago
I've updated the blog post. I don't think, though, it has any material impact on the rest of the text.
- pfg 10y ago
  Why not? Right now, compromised account keys give you the ability to issue certificates that are valid about as long as certificates are valid (or, in the worst case, +90 days from the original expiration date). Just about any scenario where the account key is compromised is one where the certificate's private key is compromised as well (not to mention typically one where you can just solve another challenge), so you're not really in a much worse position. Even less of a concern once authorizations are valid for only ~7 days.
- lol768 10y ago
  > I've updated the blog post You still state in your updated post that: "The surprising aspect is that Authz has a validity of 300 days (which is likely to be increased)" [emphasis mine]. This would appear to be incorrect based on the source cited above , where it is stated at "Eventually, we'd like to make authorization objects much shorter than certificate lifetimes, probably 7 days." Perhaps it's worth updating the post again in light of this?
  - dc352 10y ago
    It is an interesting one - here is the original source (and there were many more mentioning 300 days). https://community.letsencrypt.org/t/dns-authorization-lifetime-on-le-servers/17007/2 https://community.letsencrypt.org/t/dns-authorization-lifeti... It is from 14 June 2016 (a few months back), @pfg states "The CA/B Forum is currently developing new rules for domain validation and is probably going to settle on a validation period that is significantly longer than the 300 days currently in use ..." Is there an authority to say which way it will go?
    - pfg 10y ago
      I think it's 36 months right now, but that's a Baseline Requirements thing, Let's Encrypt can (and does) use shorter periods. 36 months is the upper limit for all CAs. Let's Encrypt currently uses 90 days, and will go to something like 7 days in the near-future[1]. [1]: https://community.letsencrypt.org/t/upcoming-api-changes/17947 https://community.letsencrypt.org/t/upcoming-api-changes/179...
- lightedman 10y ago
  If you don't mind, I'd like to add to your blog post. Token issues are something we solved about a decade ago. As to why LetsEncrypt has yet to learn these lessons, I leave that as an exercise to the readers and those familiar with security issues to discover for themselves.
  - dc352 10y ago
    Can I attribute this to a particular name?
lightedman 10y ago
The authorization lifetime should only last a few hours if that at best. Let's Encrypt is slowly learning the lessons one should have learned a decade ago regarding tokens. That does not give me hope for their future.
- pfg 10y ago
  This is not a traditional token use-case (as you would use for e.g. a password reset email). We're talking about long-term identity keys (the account key) which are associated with authorizations for FQDNs, giving the owner of that key the ability to issue certificates for those FQDNs. The risk is not related to any kind of token, but rather to losing the long-term identity key, which really is no different from losing credentials for a more traditional CA (who can re-use these authorizations for up to 36 months).
  - lightedman 10y ago
    The risk is that you're not using instantly-terminating tokens. I've had over 20 years (way longer if you count BBS systems which had the exact same problems then as we have now) to play with this. I retired on this very concept.
    - icebraining 10y ago
      How do authenticate yourself to get a new instantly-terminating token?
vizza 10y ago
The cert cabel needed to be disrupted. We are saving 37 * $69 (GoDaddy standard cert price) yearly. 90 day certs can be an issue when you have gobs of them. LetsEncrypt emails the admin before expiration, and they provide an automated way to renew. However, we have 37 certs, which means on average one is expiring roughly every three days. The renewal process can fail and the emails may go to spam or to someone not available. We needed external monitoring with escalating alerts, so we built https://LetsMonitor.org https://LetsMonitor.org (forever totally free) to address this. Please feel free to use it. Again, it is totally, forever free. It is simply a project we built for our own purposes and made public.

by veeti 10y ago

dc352 10y ago

I've updated the blog post. I don't think, though, it has any material impact on the rest of the text.

pfg 10y ago
Why not? Right now, compromised account keys give you the ability to issue certificates that are valid about as long as certificates are valid (or, in the worst case, +90 days from the original expiration date). Just about any scenario where the account key is compromised is one where the certificate's private key is compromised as well (not to mention typically one where you can just solve another challenge), so you're not really in a much worse position. Even less of a concern once authorizations are valid for only ~7 days.
lol768 10y ago
> I've updated the blog post You still state in your updated post that: "The surprising aspect is that Authz has a validity of 300 days (which is likely to be increased)" [emphasis mine]. This would appear to be incorrect based on the source cited above , where it is stated at "Eventually, we'd like to make authorization objects much shorter than certificate lifetimes, probably 7 days." Perhaps it's worth updating the post again in light of this?
- dc352 10y ago
  It is an interesting one - here is the original source (and there were many more mentioning 300 days). https://community.letsencrypt.org/t/dns-authorization-lifetime-on-le-servers/17007/2 https://community.letsencrypt.org/t/dns-authorization-lifeti... It is from 14 June 2016 (a few months back), @pfg states "The CA/B Forum is currently developing new rules for domain validation and is probably going to settle on a validation period that is significantly longer than the 300 days currently in use ..." Is there an authority to say which way it will go?
  - pfg 10y ago
    I think it's 36 months right now, but that's a Baseline Requirements thing, Let's Encrypt can (and does) use shorter periods. 36 months is the upper limit for all CAs. Let's Encrypt currently uses 90 days, and will go to something like 7 days in the near-future[1]. [1]: https://community.letsencrypt.org/t/upcoming-api-changes/17947 https://community.letsencrypt.org/t/upcoming-api-changes/179...
lightedman 10y ago
If you don't mind, I'd like to add to your blog post. Token issues are something we solved about a decade ago. As to why LetsEncrypt has yet to learn these lessons, I leave that as an exercise to the readers and those familiar with security issues to discover for themselves.
- dc352 10y ago
  Can I attribute this to a particular name?

lightedman 10y ago

The authorization lifetime should only last a few hours if that at best. Let's Encrypt is slowly learning the lessons one should have learned a decade ago regarding tokens. That does not give me hope for their future.

pfg 10y ago
This is not a traditional token use-case (as you would use for e.g. a password reset email). We're talking about long-term identity keys (the account key) which are associated with authorizations for FQDNs, giving the owner of that key the ability to issue certificates for those FQDNs. The risk is not related to any kind of token, but rather to losing the long-term identity key, which really is no different from losing credentials for a more traditional CA (who can re-use these authorizations for up to 36 months).
- lightedman 10y ago
  The risk is that you're not using instantly-terminating tokens. I've had over 20 years (way longer if you count BBS systems which had the exact same problems then as we have now) to play with this. I retired on this very concept.
  - icebraining 10y ago
    How do authenticate yourself to get a new instantly-terminating token?

vizza 10y ago

The cert cabel needed to be disrupted. We are saving 37 * $69 (GoDaddy standard cert price) yearly. 90 day certs can be an issue when you have gobs of them. LetsEncrypt emails the admin before expiration, and they provide an automated way to renew. However, we have 37 certs, which means on average one is expiring roughly every three days. The renewal process can fail and the emails may go to spam or to someone not available. We needed external monitoring with escalating alerts, so we built https://LetsMonitor.org https://LetsMonitor.org (forever totally free) to address this. Please feel free to use it. Again, it is totally, forever free. It is simply a project we built for our own purposes and made public.