4 ms·

I don't think they would be considered fraudulent at all, and in fact I'm pretty sure that's the "safety valve" built into the system and why public encryption

by 5ilv3r 10y ago

I don't think they would be considered fraudulent at all, and in fact I'm pretty sure that's the "safety valve" built into the system and why public encryption is now being encouraged. I share your tinfoil hatted feelings wholeheartedly.

schoen 10y ago
> I don't think they would be considered fraudulent at all Er, by whom?
- 5ilv3r 10y ago
  Well, they would be as technically valid as any other updated cert, and they would not violate any laws since a judge somewhere would have rubber stamped it, so I just don't think that word fraudulent could apply in any actionable sense. Morally wrong, sure, but you know, politicians and law enforcement...
  - pfg 10y ago
    Fraudulent is not usually a term that's referring to legal assessments when talking about the CA system. Various browsers and root programs are (to keep the comparison) both the executive and judiciary branch of the CA system, and if certificates are issued in a way that's not allowed in those policies (which would certainly be the case in this scenario), it would be considered fraudulent and could lead to root removal.
pfg 10y ago
It would certainly be considered fraudulent by all major browser vendors, possibly leading to a death sentence for the CA (i.e. root removal) in cases of deliberate misissuance or massive negligence. Key pinning mechanisms and Certificate Transparency would make it quite likely that this kind of misissuance would be detected as well. My personal opinion on the "nation-state adversary forces CA to misissue" topic boils down to this: It's unsuitable for mass surveillance as it's easy to detect. It would work for targeted attacks, but in all likelihood your adversary will use other means to get in (zero-days, someone on the inside, physical compromise, etc.). Even for a targeted attack, my guess is that these other means would be less likely to be detected and would be significantly cheaper (if you take into account the cost of causing a root CA to get removed).
- 5ilv3r 10y ago
  How would it be identified as anything other than a routine cert rotation? You would have to have proof that you were being served different certs for the same endpoint from different devices or locations, AND find someone who cares and is not under some influence. That sounds difficult for you, but easy for a central entity to detect. Ads follow me around between devices and locations, so I am quite sure a certificate could.
  - schoen 10y ago
    The certificate is presented when fairly little information has been sent by your browser, so it's tough to target it more specifically than source IP address and OS/browser. There are a lot of ideas for catching this and some of them are starting to work, like HPKP pinning and preloads, and in the long run Certificate Transparency (including not accepting certs that haven't been publicly disclosed). If you use HTTPS Everywhere, you have an option to submit certs that you see to the EFF SSL Observatory. I don't mean to minimize the threat; I think there are lots of sites and browsers against which misissued certs can still be successfully used today without detection, and it's important to keep working on making that no longer true.
  - pfg 10y ago
    If a site uses key pinning (e.g. via HPKP), the site is in control of telling you which keys are acceptable, so there would be no way to pretend it's a routine rotation after your first site visit (unless the site is cooperating, in which case you're screwed anyway). Certificate Transparency would also help here, as it would allow site owners to monitor the logs for any certificates they did not request. This is more about detection as opposed to prevention (though the chilling effect of easier detection would help with prevention, I suppose). Admittedly, this is probably something only a couple of large, security-conscious organizations do (like, for example, Facebook, which detected that someone was issuing certificates against internal policy, though not maliciously in that case).

by 5ilv3r 10y ago

schoen 10y ago

> I don't think they would be considered fraudulent at all Er, by whom?

5ilv3r 10y ago
Well, they would be as technically valid as any other updated cert, and they would not violate any laws since a judge somewhere would have rubber stamped it, so I just don't think that word fraudulent could apply in any actionable sense. Morally wrong, sure, but you know, politicians and law enforcement...
- pfg 10y ago
  Fraudulent is not usually a term that's referring to legal assessments when talking about the CA system. Various browsers and root programs are (to keep the comparison) both the executive and judiciary branch of the CA system, and if certificates are issued in a way that's not allowed in those policies (which would certainly be the case in this scenario), it would be considered fraudulent and could lead to root removal.

pfg 10y ago

It would certainly be considered fraudulent by all major browser vendors, possibly leading to a death sentence for the CA (i.e. root removal) in cases of deliberate misissuance or massive negligence. Key pinning mechanisms and Certificate Transparency would make it quite likely that this kind of misissuance would be detected as well. My personal opinion on the "nation-state adversary forces CA to misissue" topic boils down to this: It's unsuitable for mass surveillance as it's easy to detect. It would work for targeted attacks, but in all likelihood your adversary will use other means to get in (zero-days, someone on the inside, physical compromise, etc.). Even for a targeted attack, my guess is that these other means would be less likely to be detected and would be significantly cheaper (if you take into account the cost of causing a root CA to get removed).

5ilv3r 10y ago
How would it be identified as anything other than a routine cert rotation? You would have to have proof that you were being served different certs for the same endpoint from different devices or locations, AND find someone who cares and is not under some influence. That sounds difficult for you, but easy for a central entity to detect. Ads follow me around between devices and locations, so I am quite sure a certificate could.
- schoen 10y ago
  The certificate is presented when fairly little information has been sent by your browser, so it's tough to target it more specifically than source IP address and OS/browser. There are a lot of ideas for catching this and some of them are starting to work, like HPKP pinning and preloads, and in the long run Certificate Transparency (including not accepting certs that haven't been publicly disclosed). If you use HTTPS Everywhere, you have an option to submit certs that you see to the EFF SSL Observatory. I don't mean to minimize the threat; I think there are lots of sites and browsers against which misissued certs can still be successfully used today without detection, and it's important to keep working on making that no longer true.
- pfg 10y ago
  If a site uses key pinning (e.g. via HPKP), the site is in control of telling you which keys are acceptable, so there would be no way to pretend it's a routine rotation after your first site visit (unless the site is cooperating, in which case you're screwed anyway). Certificate Transparency would also help here, as it would allow site owners to monitor the logs for any certificates they did not request. This is more about detection as opposed to prevention (though the chilling effect of easier detection would help with prevention, I suppose). Admittedly, this is probably something only a couple of large, security-conscious organizations do (like, for example, Facebook, which detected that someone was issuing certificates against internal policy, though not maliciously in that case).