I wholeheartedly agree that revocation is a must within the required 
timeframes. We've had automation being used as an excuse for delayed 
revocation, but I don't think that's telling us the full story. There is 
the elephant in the room that the CA industry is a commercial operation, 
and automation can be seen as another revenue point. Repeated revocations 
in a short timeframe also impact subscriber relations and provide perverse 
incentives to a CA in how they handle incident response.

To that end I want CAs to consider if they, or competitors, are charging 
for automation and what benefits that brings to the WebPKI ecosystem. Of 
course, there is a difference between charging for support personnel in 
configuring the environment vs responding to ACME requests. I doubt this 
will be a public topic, but please consider it in your private discussions 
however.

On Thursday, May 30, 2024 at 9:20:33 AM UTC+1 Tim Callan wrote:

> Today we see many CAs who don’t want to go through a forced revocation 
> event who use their Subscribers’ ostensible incompetence as an excuse for 
> their own failed CA operations.  This can only be either deliberate 
> misdirection or extreme ignorance and misunderstanding of the 
> responsibilities and nature of a public CA.
>
>  
>
> It’s quite simple.  The CA’s responsibility is to perform the revocation 
> within the allocated timeframe.  That’s all.  The Subscriber’s 
> responsibility is to deploy replacement certificates from the misissuing CA 
> or another, on time to avoid an outage or not.  The CA’s responsibility 
> does not extend to the Subscriber’s certificate agility or lack thereof.  
> It does not include the Subscriber’s process or involved parties or 
> governing law.  It does not include the nature, severity, duration, or 
> likelihood of a resulting outage.
>
>  
>
> This is all the Subscriber’s responsibility.  The risk/reward analysis of 
> running an operation that cannot weather a forced revocation event is the 
> Subscriber’s to calculate.  The consequential process and resourcing 
> decisions are the Subscriber’s to make.  The public-versus-private trust 
> analysis is something only the Subscriber can conduct.
>
>  
>
> Which is appropriate, since the Subscriber has to live with the 
> consequences.  In the event of a forced revocation, if the Subscriber 
> deploys the new, replacement certs on time, then everything continues to 
> run.  And if not, then not. 
>
>  
>
> This is the only conceivable model that can actually work.  There is no 
> mechanism for CAs to reliably determine if “critical infrastructure” uses 
> their certificates and no clear definition of what qualifies as critical.  
> There is no way for a CA to realistically evaluate the consequences of a 
> revocation event.  And unfortumately, we have a healthy dose of empirical 
> evidence telling us that Subscribers are unreliable reporters of the nature 
> of their own services and the severity of downtime.
>
>  
>
> There is research 
> <https://groups.google.com/a/mozilla.org/g/dev-security-policy/c/J3aX8OKIT_A/m/xB723PIsAQAJ>
>  
> suggesting that three quarters of CAs with current mandatory revocation 
> events are not getting them done in five days, and that at 30 days in, 
> multiple CAs still have more than 95% of their certificates unrevoked.  If 
> my memory serves me correctly, 100% of these CAs have blamed their 
> revocation failure on Subscribers’ inability to swap out these certs and 
> the terrible consequences of a potential outage.  These CAs would have us 
> believe that more than 95% of their certificates enable critical 
> functionality that cannot undergo an outage without such disastrous 
> consequences that they warrant throwing out the only error mitigation 
> mechanism the WebPKI possesses. It defies credibility that this is true for 
> any CA in the world, let alone three quarters of those with a misissuance 
> event.
>
>  
>
> Our own experience with forced revocation events here at Sectigo has shown 
> us that Subscribers will always ask for more time.  They will always say 
> they can’t get it done and that the effect of not getting it done will be 
> disaster.  That makes sense.  An unscheduled certificate replacement 
> exercise is inconvenient for the Subscriber.  It takes time that could be 
> spent on other tasks.  It adds hassle and worry.  It may cost overtime or 
> incremental service budget.  Of course the Subscribers don’t want to do it, 
> so when they are allowed to choose, they choose not to.
>
>  
>
> But when the CA simply offers that this revocation will occur in a 
> specified timeframe, the Subscribers miraculously get the new certificates 
> deployed.  Every time.  We see this miracle occur over and over again.
>
>  
>
> It could be that Sectigo has the luckiest and most competent set of 
> Subscribers on the planet.  Or maybe, just maybe, the fact is that nearly 
> all Subscribers can handle a forced revocation event when it occurs.  They 
> simply don’t want to.  If CAs had sufficient emotional fortitude and 
> commitment to the principles they had signed up for, they would complete 
> all these revocations on time, and the Subscribers would manage to deploy 
> their new certificates, and we wouldn’t be having this conversation.  But 
> the evidence overwhelmingly tells us that CAs do not.
>
>  
>
> So what we need is for this decision to stay out of the CA’s hands.  In 
> fact, by the BRs and root program rules as written, with the exception of 
> Mozilla, CAs do not have the authority to make this decision today.  It’s 
> just that the CAs are nonchalantly violating these rules and for the most 
> part there have not yet been visible consequences.  (Though we should note 
> the likelihood that mismanagement of revocations was a contributing factor 
> in the recent distrust of ecommerce monitoring GMBH.)
>
>  
>
> It is within the power of major root programs to affect policies and/or 
> software functionality that will change CAs’ risk/reward decisions.  This 
> can be threat of distrust but also could include less severe consequences.  
> Community participants have suggested ideas including capping the maximum 
> term for offending CAs at 90 days, distrusting the EV roots of offending 
> CAs, and enforcing a browser-side ban on misissued certificates after the 
> revocation deadline.  These are all technically possible, and each root 
> program will evaluate if one of these ideas, or another, makes sense.
>
>  
>
> I personally believe that any of these outcomes would have been 
> motivational for most or all of the current offending CAs to complete their 
> revocations on time.  I further believe that, in the absence of a completed 
> revocation, they would have meaningful mitigating effects on these and 
> future incidents from the same CAs.
>
>  
>
> -tlc
>
>  
>
>  
>
> *From:* [email protected] <[email protected]> *On Behalf Of *Mike Shaver
> *Sent:* Friday, May 24, 2024 5:41 PM
> *To:* Aaron Gable <[email protected]>
> *Cc:* [email protected]
> *Subject:* Re: issuance to subscribers who cannot tolerate prompt 
> revocation
>
>  
>
> CAUTION: This email originated from outside of the organization. Do not 
> click links or open attachments unless you recognize the sender and know 
> the content is safe.
>
>  
>
> On Fri, May 24, 2024 at 5:22 PM Aaron Gable <[email protected]> wrote:
>
> On the whole, I certainly agree with your sentiment here: Subscribers who 
> cannot replace a certificate in less than 5 days are not protecting the 
> privacy and the security of their users, and either need to improve their 
> response time or investigate non-WebPKI solutions. And CAs which knowingly 
> issue to such Subscribers (perhaps because that Subscriber has failed to 
> replace a certificate in a prior incident) are asking for trouble.
>
>  
>
> The problem is this: the “trouble” is being pushed onto the users of 
> WebPKI, because the Subscriber’s unwillingness to accept prompt revocation 
> is used along with what I think is bad faith abuse of the latitude provided 
> to CAs to unilaterally delay revocation and therefore keep misissued 
> certificates in use for an extended period of time (more than a month in 
> some cases!).
>
>  
>
> This represents real risk for the web, not only because in the event of a 
> key compromise, if the pronouncements of the CAs in question are true, we 
> would have to choose between an insecure web and harm to human health or 
> critical infrastructure. Having misissued certificates (of any kind) in 
> circulation harms the ability of WebPKI users to rely on the BRs’ 
> guarantees, and risks interoperability issues for new entrants.
>
>  
>
> Section 1.4.2 of the CPS does not have any requirement that WebPKI 
> certificates not be used in critical contexts, but if we are told that it 
> is disastrous to revoke these certificates in a timely manner, then perhaps 
> there should be some minimum exclusions. (Perhaps there is a CA who 
> genuinely believes that their certificates are reliable enough for such 
> uses, though? A scan of some CPSes sort of indicates that, but I expect it 
> is more omission than deliberate choice.)
>
>  
>
> But I also think that issuing to such a Subscriber is not necessarily 
> itself a misissuance. The Subscriber has agreed to a legally binding 
> Subscriber Agreement which includes the necessary warranties. It is not 
> *necessarily* the CA's fault -- though it is their problem -- that the 
> Subscriber has failed to understand the full ramifications of that warranty.
>
>  
>
> I honestly don’t care about whose fault it is, just how to avoid this 
> pattern repeating. Some of these Subscribers have been using a given CA’s 
> certs for longer than the BRs have existed, and—barring *force majeure* use 
> of something like OneCRL—the CAs are the only ones who can keep the risk 
> and harm from being externalized to the users who rely on the WebPKI. CAs 
> are knowingly entering into these arrangements, and if you’re correct that 
> it’s not a misissuance then I don’t understand what point 8 being in the 
> baseline requirements is.
>
>  
>
> Relatedly, what is the purpose of requiring the acknowledgements of that 
> section to be legally binding, if the CAs don’t have a responsibility to 
> use that legal tool and revoke misused certificates? Any CA could 
> themselves add such a clause to their terms if they wanted it themselves, 
> but unfortunately I do not recall the motivation for making such a 
> requirement part of the BRs. Maybe it’s in mailing list archives?
>
>  
>
> Mike
>
>  
>
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