It's worth pointing out that the latest draft of the domain validation ballot[1] written by the CA/B Forum Validation WG set the authorization lifetime at 39 months:
> Completed confirmations of Applicant authority may be valid for the > issuance of multiple certificates over time. In all cases, the > confirmation must have been initiated no more than 39 months prior to > certificate issuance. This begs the question of whether significantly reducing the authorization lifetime in ACME will result in any real-world security improvement, given that non-ACME CAs could continue to operate with lifetimes of up to 39 months. Boulder's current choice of 10 months is probably a concession to the fact that some environments are still having a hard time when it comes to automating the challenges described in ACME. With the current lifetime of 10 months and a certificate lifetime of 3 months, even a challenge solved manually will get you certificate coverage for up to a year, which is comparable to traditional CAs. [1] https://cabforum.org/pipermail/public/2016-April/007234.html On 22/04/16 13:00, Hugo Landau wrote: > Indeed. I also don't see the need for long authorization lifespans. > Removing autorenewal would complement this well, and simplify the > protocol. > > Hugo Landau > > On Thu, Apr 21, 2016 at 11:24:54PM +0200, Benjamin Hof wrote: >> Hi, >> >> Reading the ACME 02 draft, I have a concern regarding the identifier >> authorization life time. >> >> Given a compromised TLS server, the attacker can solve an ACME challenge >> and be authorized for the hosts's name. This authorization can then be >> used to obtain valid certificates, even after the intrusion has been >> stopped, for as long as the authorization is valid (ten months in >> boulder). >> >> This risk comes in addition to common DV exposure and is present for >> (almost) any TLS server, not only the ones using ACME. >> >> If the above holds, it would appear beneficial if the authorization was >> valid only briefly: as long as it takes to obtain the desired >> certificates. >> >> Is there a reason to allow the long life times? >> >> >> Thanks! >> >> _______________________________________________ >> Acme mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/acme > > _______________________________________________ > Acme mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/acme > _______________________________________________ Acme mailing list [email protected] https://www.ietf.org/mailman/listinfo/acme
