I kind of feel for Actalis. It seems like they were caught between a rock and a hard place seeing as their customers were not/could not respond as quickly as hoped and revoking the certs could negatively impact end-users by preventing them from for example obtaining prescriptions etc. The language is dense for me but it also sounded like there was a reasonable explanation in the BR for the exception (paraphrasing: ‘negatively impacting a large swath of internet users’) but it didn’t seem to assuage the concern of Ryan. I hope the Actalis guy didn’t lose his job.
From the thread is becomes painfully clear how horrible Actalis is set up to act as a CA. Instead it seems they chose to break the BR by default. Almost 5 months to reissue a little over 250k certificates is not what you may expect from a CA that a major browser should trust.
The argument that there might be some end-users unable to renew their prescription seems mostly used to gain sympathy. Also this will most probably not be “a large swath of internet users”.
I do hope Actalis step up their game and regain some trust. Or it may become the next symantec.
* The baseline requirement is 64 bits of entropy and Actalis were providing 63 bits, i.e. only short by a single bit. It would seem unusual if the baseline requirements were a mere one bit of entropy from insecurity.
* The requirement for 64 bits of entropy is to reduce the risk of hash collision attacks [1] - which have only ever been demonstrated for MD5 and SHA-1, neither of which are used to sign certificates any more.
If web security was a tightrope, this would be like hearing that the second safety net, underneath the first believed-to-be-robust safety net, was found to be strong enough to catch a 900 lbs person, when it was specified for 1000 lbs.
Mozilla recognizes that in some exceptional circumstances, revoking misissued certificates within the prescribed deadline may cause significant harm, such as when the certificate is used in critical infrastructure and cannot be safely replaced prior to the revocation deadline, or when the volume of revocations in a short period of time would result in a large cumulative impact to the web. However, Mozilla does not grant exceptions to the BR revocation requirements. It is our position that your CA is ultimately responsible for deciding if the harm caused by following the requirements of BR section 4.9.1 outweighs the risks that are passed on to individuals who rely on the web PKI by choosing not to meet this requirement.
That statement "may cause significant harm" is what I expect weighed on the CA's mind. When revoking a certificate could kill someone, and there is still a high barrier to exploit (i.e. no "proven method that exposes the Subscriber's Private Key to compromise") it should be up to the CA to clearly explain the situation, and up to Ryan to accept the explanation given. ("It is our position that your CA is ultimately responsible for deciding if the harm [...] outweighs the risks")
Clearly Actalis was not in a position to articulate the harm, which is their fault.
That said, I'm fully aware of the compliance hoops that must be jumped through when providing updates to medical devices. If you have to distribute firmware to medical devices, 4 months can be a remarkably fast turnaround. But in that case, CA-issued certificates are probably inferior to self-signed certificates (on an organisational level) that are not subject to external revocation.
I agree it's on them to get it right. It just seem extenuating circumstances at least played a roll. I think I quoted the wrong part of the BR - it was adjacent to the large amount of users part - but was more along the lines of negatively impacting safety or security or somesuch.
From my limited POV, this seems like collateral damage from overblowing the trivial bug they used to beat the DarkMatter CA over the head.
I didn’t find the arguments of severity convincing then either. But the gist was that they need to be completely consistent and rigorous so it does make sense even if it is a massive inconvenience for people. Again.
> it also sounded like there was a reasonable explanation in the BR for the exception
I believe this is due to Actalis misunderstanding the exception. Mozilla provides an exception for exceptional circumstances which Actalis's obviously were not.
