Their customers would be forced to give their business to Honest Achmed[1].
Where’s a billionaire troll when you need one? (And a form of billionaire trolling that would upset a lot less people than Musk’s version of it.)
Would be even funnier if the billionaire’s name actually was Achmed
Interesting, I hadn’t heard that, is there anywhere I can read more about it?
> You could purchase a root off an existing CA,
As well as a sub-CA, I remember in theory you can have two independent CAs with cross-signing… but do browsers actually support that?
Sub-CAs: Not really. Operational risk to the parent CA is huge, you'd be hard pressed to get any current public CA to sign an issuing CA to be operated externally. Cross-signing still works (though it is the stuff of nightmares in many cases) but again you have to have money and a CA willing to do it!
Anyone can get a cert from lets-encrypt. No users of your website care how trustworthy your CA is. And CA's are too big to fail, so you barely need to worry about your CA being removed by the trust store. So you can only compete on price.
If we want to change this, we need a way for a certificate to be co-signed by multiple CA's. So that the certificate can be presented to the user, and they can figure out if any trusted CA of theirs has signed the certificate. This way, revoking trust in a CA becomes easier, because people should have multiple signatures on their certificate. That means, all of a sudden, that the quality of a CA actually matters.
Whilst it might seem this is already possible, it is not. Cross-signing is only a thing for intermediate certificates, and does not work. You can also have multiple certificates for the same key, but when starting a TLS session, you must present a single certificate. (This seems to have changed for TLS 1.3, so perhaps this is already possible?)
In theory, you could make an intermediate CA and get cross signed certs from multiple CAs (hopefully with Name Constraints), your intermediate CA signs your server cert, and you include all your cross certs and the intermediate certs for those. And the client figures out which chains it can make and if it likes any of them.
But experience has shown, verification may find a chain with signatures that line up, but the CA is expired or revoked in the local trust store, and reject the verification, even though another chain could have been found with the provided certificates.
And, because of the limited information in tls handshakes from real world clients, it's difficult (maybe impossible) to know which CAs a client would accept, so that the server could present an appropriate chain.
> 2. Sub CAs Operated by 3rd Parties
> Honest Achmed's uncles may invite some of their friends to issue certificates as well, in particular their cousins Refik and Abdi or "RA" as they're known. Honest Achmed's uncles assure us that their RA can be trusted, apart from that one time when they lent them the keys to the car, but that was a one-off that won't happen again.
How many will agree to that removal? How many will see one more reason to forever turn off automatic updates and decide what to trust themselves, having seen yet another way some faceless entity they never knew about can break things?
It will certainly send a strong message, but likely not the intended one. All it will do is increase the lack of trust in centralised PKI in general.
I'm not arguing that it's good that a relatively small number of entities (mainly Google, Microsoft and Mozilla) decide which CAs are trustworthy, but that's all the more reason that it's important for all of this Web PKI work to happen completely in the open, so that the few who can spare the time and effort to scrutinize what is going on can help the rest of us have a safer Internet. We don't have a better solution. That's also why DigiCert issuing legal threats because they don't like how one of these issue reports makes them look is a serious problem that can't be tolerated.
I'd imagine that they wouldn't do it to "take a stand" so much as "avoid the risk of getting their stuff broken in the short term" in this scenario, regardless of whichever party loses the blame game. See: the recent WordPress drama, which has turned customers away from both parties involved.
On the flip side, for user impact, it will play out like this: Some bank or other important entity could possibly, for whatever reason, continue using a (presumably expired? unless DigiCert continues issuing anyways; note that most likely, they will not.) DigiCert certificate after the cut off date, which will lead to users receiving errors. Some of them will have HSTS setup, which will lead to an emergency situation where they have to issue a new certificate ASAP, as it will basically halt their business until they do. For places where there is no HSTS, users may be instructed to simply bypass the certificate warning temporarily, and support lines will be absolutely swamped until they actually fix the problem.
The WordPress situation is quite different. You don't have to use WordPress. Users don't even know what the Web PKI is to find an alternative to it, not that there is one or will be one.
They don't have free rein to do whatever they want. If they chose to remove them, they are going to have to be ready to defend themselves in court.
If the browsers removed DigiCert, DigiCert could certainly sue based on the harm to their business. They could argue that the browser vendors were inconsistent with the application of their rules. They could argue that the browser vendors were unfairly competing by kicking them out.
Not saying they would win all these, but they would certainly fight it - the alternative would be the end of DigiCert, they aren't going to go down without a fight in whatever venue they can find.
... and DigiCert did not try to appeal the TRO.
...unless they notice the breakage, and you tell them to do so to stop it.
That all assumes DigiCert continues issuing certificates they know won't be trusted. I assume most likely what will actually happen is they have to start selling certificates from another CA, but failing that they're probably just going to stop issuing certificates before the cutoff.
Note that this is not a "both" but a "any of them". One can disagree with the other on this and still cause wide breakage.
This gives certificate owners ample time to look for a different issuer and no certificate buyer would deliberately purchase a certificate from an issuer when they know some percentage of users will not trust that cert.
So for the end users, everything will keep working: the existing digicert certs stay valid and newly refreshed certs will be signed by a different authority. There is no need to turn off automatic updates over this.
Between Entrust and Symantec, we've already seen this happen to large well-known CAs and everything remained fine (not for the offenders, but, hey, that's the system working as intended)
“In general” is a broad statement, given that the overwhelming majority of people using the Web PKI have no idea that they’re doing so. DigiCert is not a legible part of the value chain for the average users; they won’t notice that the sites they use switch CAs. This strong disfavoritism towards vendors is arguably one of the Web PKI’s greatest strengths.
The most recent digicert thread smells suspiciously similar to those that lead up to the Entrust debacle.
Trust stores and Browsers specifically have more options than simply remove a CA. A more reasonable approach for distrust process of a CA this size would be to stop accepting any new certificates issued after a certain date. Then existing customers will have a heads up and even if asleep will find out the bad news during scheduled renewal rather than while the responsible employees are on vacation.
https://security.googleblog.com/2017/09/chromes-plan-to-dist...
There are a lot of efforts to get name constraints widely supported, so a given CA can only issue for certain TLDs or even domains, but it's still not there. That could be a viable punishment for misbehaving CAs in the future, or even an intentionally chosen restriction for CAs that want less strict requirements. Government CAs could be a very useful application, if a CA cert could be name constrained to only issue for .gov.cctld at that point we could basically just let them do whatever they want without concern. Likewise for any small regional CAs, if they could be limited to only regional TLDs their blast radius is reduced which also could mean less strict requirements than those applied to CAs able to sign for .com.
It would also be useful for localhost. Create a private CA that is constrained to localhost and *.local, and you don't have to worry about it being used to MitM other sites if it gets compromised.
Obviously having a glut of new private CAs would cause scalability issues for CT logs that are already having issues keeping up with current uses, perhaps CT requirements could be reduced for such single-domain CAs in combination with limited lifetimes.
Of course, I think that is unlikely, but on the other hand, it's just as cathartic to imagine whatever idiot at DigiCert thought it was a good idea to engage legal here to have the dressing down of a lifetime. I read the thread in question. It doesn't make DigiCert look good, but this action definitely is more damning to them than anything Collan said in my opinion.