3 ms·

If I understand certificate transparency correctly, StartCom's actions will be fully and publicly auditable, in real time. This means one vector of attack : Ch

If I understand certificate transparency correctly, StartCom's actions will be fully and publicly auditable, in real time. This means one vector of attack : Chinese government requesting google.com certificate from them, and MITMing it's citizen would not be possible. To any CT experts: is my assessment correct?

lima 9y ago
Only if SCT stapling is enforced (certificate only valid if is includes a proof of inclusion).
geofft 9y ago
One, it's notice of attack, not prevention of attack. StartCom (or an attacker in possession of their private key) can issue a perfectly valid google.com certificate, it's just going to be visible to the world that that's what happened. Two, while Google is presumably watching CT logs for google.com certificate issuances, I'm certainly not watching my personal website. I suspect most people aren't, so they could probably get away with issuing e.g. a shadowsocks.org certificate and have a few days of successful attack before anyone notices. This is probably not what you want for dragnet surveillance, but it's great for an attack against an individual (whether conducted by a government or just some private party). So yes, the state of the world is quite a bit better than it was before CT, but adding CAs remains a risk. They're only worth adding if there's a reason to do it. (StartCom's free certificates used to be a really good reason.)
- ameliaquining 9y ago
  There are various free services that will email you whenever a cert for one of your domains shows up in the CT logs. It's a good idea to sign up for one. (It would be an even better idea for domain registrars to automatically sign you up for one.) Here's one that Facebook operates: https://developers.facebook.com/tools/ct/ https://developers.facebook.com/tools/ct/

3 ms·

If I understand certificate transparency correctly, StartCom's actions will be fully and publicly auditable, in real time. This means one vector of attack : Ch

by anilgulecha 9y ago

lima 9y ago
Only if SCT stapling is enforced (certificate only valid if is includes a proof of inclusion).
geofft 9y ago
One, it's notice of attack, not prevention of attack. StartCom (or an attacker in possession of their private key) can issue a perfectly valid google.com certificate, it's just going to be visible to the world that that's what happened. Two, while Google is presumably watching CT logs for google.com certificate issuances, I'm certainly not watching my personal website. I suspect most people aren't, so they could probably get away with issuing e.g. a shadowsocks.org certificate and have a few days of successful attack before anyone notices. This is probably not what you want for dragnet surveillance, but it's great for an attack against an individual (whether conducted by a government or just some private party). So yes, the state of the world is quite a bit better than it was before CT, but adding CAs remains a risk. They're only worth adding if there's a reason to do it. (StartCom's free certificates used to be a really good reason.)
- ameliaquining 9y ago
  There are various free services that will email you whenever a cert for one of your domains shows up in the CT logs. It's a good idea to sign up for one. (It would be an even better idea for domain registrars to automatically sign you up for one.) Here's one that Facebook operates: https://developers.facebook.com/tools/ct/ https://developers.facebook.com/tools/ct/