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Doesn't the CA have one move left in this game of brinkmanship? They can start brazenly backdating their new certificates to fall into the accepted window, whic
by caf 10y ago
Doesn't the CA have one move left in this game of brinkmanship? They can start brazenly backdating their new certificates to fall into the accepted window, which would leave us right back at holding their own customer base hostage.
- ge0rg 10y agoThis is addressed in the document as well: WoSign/StartCom could back-date certificates to get around this restriction. And there is, as we have explained, evidence that they have done this in the past. However, many eyes are on the Web PKI and if such additional back-dating is discovered (by any means), Mozilla will immediately and permanently revoke trust in all WoSign and StartCom roots. If the CA really goes that route, it will be clear malicious behavior and therefore a good reason to permanently ban the CA.
- luminiferous 10y agoRight, and that's fine and good for WoSign/StartCom. But what if they handed out a one year restriction to a much larger CA like Comodo, or Symantec? And that CA decided to back-date their certificates? Then we still have the problem of large CAs being able to effectively ignore these restrictions because of their large userbase. As long as such CAs are able to set the notbefore arbitrarily, they can backdate as much as they'd like. The only solution I can think of is to have some kind of giant database of all certificates seen in the wild that were issued by said CA, and not trust any new ones. (This may be something that can be done with Certificate Transparency, but I haven't read enough on that to be sure.) This would allow Mozilla/Apple/Microsoft to actually block new certificates.