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I'm tired of downvotes without explaination. You don't see a problem with a new automation that when breaks basically brings down your website? Or any problem w

I'm tired of downvotes without explaination. You don't see a problem with a new automation that when breaks basically brings down your website? Or any problem with letsencrypt basically giving you only <90 days to generate a cert with somebody else? I also really want to have the argument for improved security. Because a compromised host can now generate new certs for himself at zero cost as well, so what's the real point behind the 90 day limit? Giving NSA less time to crack your key? Thanks for clarifying.

simoncion 11y ago
> You don't see a problem with a new automation that when breaks basically brings down your website? A TLS cert change doesn't bring down your website. Swap the old cert for the new and reload. Done. > Or any problem with letsencrypt basically giving you only <90 days to generate a cert with somebody else? Look at the folks behind the project. Take a good look at the folks running and funding the project. They know how to run an essential Internet service. Moreover, they will give you more than 90 days notice if they ever need to shut Let's Encrypt down. Frankly, you can level this criticism at any vendor that's a potential SPoF. It's not a good complaint when it's so general. > Because a compromised host can now generate new certs for himself at zero cost as well... Because -AIUI- CRLs don't currently work well -in practice-, a 90 day window of cert validity limits the amount of time a given cert can be out in the wild, impersonating your site. > ...what's the real point behind the 90 day limit? Giving NSA less time to crack your key? If I might snark for a second: 1) If your box is pwnd, and your private keys aren't in an HSM, then there's no need to try crack your key. 2) AFAIK, there is no non-brute force attack against the public part of a correctly generated TLS keypair that will reveal the private part of the key. (Or am I totally wrong about how TLS works, and there's only a private key? I can't remember. :( )
- dingaling 11y ago
  > a 90 day window of cert validity limits the amount of time a given cert can be out in the wild, impersonating your site. But a the OP pointed-out, if a site using LE is compromised then the attacker has basically an infinite duration of valid certs, because they are automatically renewed. There is no manual challenge to receive a new cert. So essentially the validity period of an LE cert means nothing.
  - zeendo 11y ago
    ...that's only true while the attacker controls the site. The 90 day window mitigates the effect of the cert being leaked. Just because I grabbed a site's cert on day doesn't mean I control the site. In fact, there's nothing to say I even compromised the site to get the cert in the first place. Perhaps it was mishandled internally? Or grabbed via a heartbleed-style attack?
  - simoncion 11y ago
    > But a the OP pointed-out, if a site using LE is compromised then the attacker has basically an infinite duration of valid certs, because they are automatically renewed. As zeendo mentions, this is only true while the attacker can continue to provide proof that they control the site in question. > There is no manual challenge to receive a new cert. You're talking about a server on which an attacker has the ability to * Read the server's ACME private key And one or more of * Add new documents to [scheme]://[domain]/.well-known/acme-challenge/ * Stand up a HTTPS server at the domain for which a key is being requested that responds with LE-provided data using a LE-provided temporary key. * Sign challenge information using a previously issued private key. * Add a TXT record for the domain in question containing data specified by the LE server. This requires a server to be pretty thoroughly pwnt. What's more, even though cert revocation works poorly in the real world, the LE servers almost certainly respond correctly to cert revocation requests. So, if a server operator notices that his box has been pwnt, he can revoke the certs that were issued during the time, closing the "Sign challenge info using a previously issued LE key" barn door for good. (Or until his machine gets pwnt again.) Frankly, I think that OP hasn't actually had a good look at how the LE software works, or the design of ACME.

simoncion 11y ago

> You don't see a problem with a new automation that when breaks basically brings down your website? A TLS cert change doesn't bring down your website. Swap the old cert for the new and reload. Done. > Or any problem with letsencrypt basically giving you only <90 days to generate a cert with somebody else? Look at the folks behind the project. Take a good look at the folks running and funding the project. They know how to run an essential Internet service. Moreover, they will give you more than 90 days notice if they ever need to shut Let's Encrypt down. Frankly, you can level this criticism at any vendor that's a potential SPoF. It's not a good complaint when it's so general. > Because a compromised host can now generate new certs for himself at zero cost as well... Because -AIUI- CRLs don't currently work well -in practice-, a 90 day window of cert validity limits the amount of time a given cert can be out in the wild, impersonating your site. > ...what's the real point behind the 90 day limit? Giving NSA less time to crack your key? If I might snark for a second: 1) If your box is pwnd, and your private keys aren't in an HSM, then there's no need to try crack your key. 2) AFAIK, there is no non-brute force attack against the public part of a correctly generated TLS keypair that will reveal the private part of the key. (Or am I totally wrong about how TLS works, and there's only a private key? I can't remember. :( )

dingaling 11y ago
> a 90 day window of cert validity limits the amount of time a given cert can be out in the wild, impersonating your site. But a the OP pointed-out, if a site using LE is compromised then the attacker has basically an infinite duration of valid certs, because they are automatically renewed. There is no manual challenge to receive a new cert. So essentially the validity period of an LE cert means nothing.
- zeendo 11y ago
  ...that's only true while the attacker controls the site. The 90 day window mitigates the effect of the cert being leaked. Just because I grabbed a site's cert on day doesn't mean I control the site. In fact, there's nothing to say I even compromised the site to get the cert in the first place. Perhaps it was mishandled internally? Or grabbed via a heartbleed-style attack?
- simoncion 11y ago
  > But a the OP pointed-out, if a site using LE is compromised then the attacker has basically an infinite duration of valid certs, because they are automatically renewed. As zeendo mentions, this is only true while the attacker can continue to provide proof that they control the site in question. > There is no manual challenge to receive a new cert. You're talking about a server on which an attacker has the ability to * Read the server's ACME private key And one or more of * Add new documents to [scheme]://[domain]/.well-known/acme-challenge/ * Stand up a HTTPS server at the domain for which a key is being requested that responds with LE-provided data using a LE-provided temporary key. * Sign challenge information using a previously issued private key. * Add a TXT record for the domain in question containing data specified by the LE server. This requires a server to be pretty thoroughly pwnt. What's more, even though cert revocation works poorly in the real world, the LE servers almost certainly respond correctly to cert revocation requests. So, if a server operator notices that his box has been pwnt, he can revoke the certs that were issued during the time, closing the "Sign challenge info using a previously issued LE key" barn door for good. (Or until his machine gets pwnt again.) Frankly, I think that OP hasn't actually had a good look at how the LE software works, or the design of ACME.