That is a good question though - I think the last signed head was 7pm. That would be the actual time when all other certs shouldn't be trusted...
There is a problem though if you have a bad-acting CA since the notBefore date could be before 7pm and the browsers don't check to see if it was included in the tree before that time. However, that is the reason to include multiple SCTs in the same log. -----Original Message----- From: dev-security-policy <dev-security-policy-boun...@lists.mozilla.org> On Behalf Of Jeremy Rowley via dev-security-policy Sent: Sunday, May 3, 2020 5:27 PM To: Alex Cohn <a...@alexcohn.com> Cc: Mozilla <mozilla-dev-security-pol...@lists.mozilla.org> Subject: RE: CT2 log signing key compromise They would already appear in a previous tree where the head was signed by us. From: Alex Cohn <a...@alexcohn.com> Sent: Sunday, May 3, 2020 5:22 PM To: Jeremy Rowley <jeremy.row...@digicert.com> Cc: Mozilla <mozilla-dev-security-pol...@lists.mozilla.org> Subject: Re: CT2 log signing key compromise The timestamp on a SCT is fully controlled by the signer, so why should SCTs bearing a timestamp before May 2 still be considered trusted? Alex On Sun, May 3, 2020 at 6:19 PM Jeremy Rowley via dev-security-policy <dev-security-policy@lists.mozilla.org<mailto:dev-security-policy@lists.mozilla.org>> wrote: Hey all, The key used to sign SCTs for the CT2 log was compromised yesterday at 7pm through the Salt root bug. The remaining logs remain uncompromised and run on separate infrastructure. We discovered the compromise today and are working to turn that log into read only mode so that no new SCTs are issued. We doubt the key was used to sign anything as you'd need to know the CT build to do so. However, as a precaution, we ask that you consider all SCTs invalid if the SCT was issued from CT2 after 7pm MST on May 2nd . Please let me know what questions you have. Jeremy _______________________________________________ dev-security-policy mailing list dev-security-policy@lists.mozilla.org<mailto:dev-security-policy@lists.mozilla.org> https://lists.mozilla.org/listinfo/dev-security-policy _______________________________________________ dev-security-policy mailing list dev-security-policy@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-security-policy _______________________________________________ dev-security-policy mailing list dev-security-policy@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-security-policy
