That doesn't particularly matter; if someone takes over the domain but doesn't have a leaked key, they can't sign requests for the domain with my cert. It takes a leaked key for this to turn into a vulnerability.
On the other hand, anyone that owns the domain can get a perfectly valid cert any time, no need to exploit anything. And given that nobody actually looks at the details of the cert owner in practice, that means that if you lose the domain, the new owner is, treated as legit. No compromises needed.
The only way to prevent that is to pin the cert, which this short rotation schedule makes harder, or pin the public key and be very careful to not regenerate your keys when you submit a new CSR.
In short: Don't lose your domain.
> Compared to a year?
Typically these kinds of things have an exponential dropoff, so most of the exploited folks would be soon after the compromise. I don't think that shortening to this long a period, rather than (say) 24h would make a material difference.
But, again, I'm also not sure how many people were compromised via anything that this kind of rotation would prevent. It seems like most exploits depend on someone either losing control over the domain (again, don't do that; the current issuance model doesn't handle that), or just being phished via a valid cert on an unrelated domain.
Do you have concrete examples of anyone being exploited via key mismanagement (or not proving often enough that they have control over a domain)?
This reminds me a bit of trying to get TLS 1.2 support in browsers before the revelation that the older versions (especially SSL3) were in fact being exploited all the time directly and via downgrading. Since practically nobody complained (out of ignorance) and, at the time, browsers didn't collect metrics and phone home with them (it was a simpler time), there was no evidence of a problem. Until there was massive evidence of a problem because some people bothered to look into and report it. Journalism-driven development shouldn't be the primary way to handle computer security.
It does, if someone gets temporary access, issues a certificate and then keeps using it to impersonate something. Now the malicious actor has to do it much more often, significantly increasing chances of detection.
It's not only key mismanagement that is being mitigated. You also have to prove more frequently that you have control of the domain or IP in the certificate.
In essence it brings a working method of revocation to WebPKI.
> but not low enough to prevent significant numbers of people from being compromised if there is a compromised key.
Compared to a year?