Timeline for Trying to understand why signatures in root certs "are not used"?
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
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| Sep 24, 2014 at 8:22 | comment | added | pabouk - Ukraine stay strong | @NateKerkhofs Regarding DigiNotar: A certificate authority does not issue root certificates. Root certificates are self-signed and they are on the top (root) of the CA hierarchy chain. There is no CA above them to sign the certificate. The fraudulent certificates were signed by the DigiNotar CA. ------ Extending the answer: You either trust a root certificate or not. It is your decision. The signature serves no real purpose there, it could be created by anyone. --- Hash received through a different way can be used to check the integrity of the certificate. | |
| Sep 19, 2014 at 22:20 | vote | accept | user53029 | ||
| S Sep 17, 2014 at 15:18 | history | suggested | TRiG | CC BY-SA 3.0 |
Tidied grammar.
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| Sep 17, 2014 at 15:01 | comment | added | ntoskrnl | @user53029 If you have access to a user's trust store, you could just add your own root certificate without having to mess with existing certificates for the same effect. See also Ángel's answer and the comment. | |
| Sep 17, 2014 at 14:53 | review | Suggested edits | |||
| S Sep 17, 2014 at 15:18 | |||||
| Sep 17, 2014 at 13:28 | comment | added | user53029 | Dan - thanks. That brings me back full circle. So even if TLS clients do not use the hash to verify the identity of a root cert what is stopping me from forging a CA's root cert from the SHA1 hash and potentially replacing the real CA root from the trust store with an identical copy of mine using my key pair? Would doing this allow an attacker a way to impersonate a website of perform a MiTM attack? | |
| Sep 17, 2014 at 12:50 | comment | added | Dan Is Fiddling By Firelight | @user53029 either the hash needs to be broken (which happened in 2008 with MD5 hashed certs) or the CA needs to be compromised. Most CA's use heavy physical authority including measures like keeping the root certificate itself offline to prevent catastrophic damage in the event of a hack. security.stackexchange.com/questions/24896/… | |
| Sep 17, 2014 at 11:30 | comment | added | user53029 | Thanks Nate - so if not the hash, what security measures are in place to keep the root from being faked? Does the attacker need to hack the CA like you described or is there something in the root cert itself that can be exploited? | |
| Sep 17, 2014 at 11:26 | comment | added | Nzall | @user53029 That actually happened recently. DigiNotar, a Dutch certificate authority, was hacked a few years ago and issued fraudulent root certificates for the Google domain. the hackers then managed to hack 300,000 Iranian Gmail users. DigiNotar is now bankrupt and all certificates issued by it have been revoked by every major browser. | |
| Sep 17, 2014 at 11:21 | comment | added | user49075 | @user53029: That is "a practical attack vector to impersonate a website"; it's just independent of what hash(es) was/were used in root certificate(s)'(s) self-signature(s). | |
| Sep 17, 2014 at 9:59 | comment | added | user53029 | Right but if you can fake a CA root then you can impersonate the CA, and issue your own leaf's down to the identity, is this not a practical attack vector to impersonate a website? | |
| Sep 17, 2014 at 8:49 | history | answered | Uwe Plonus | CC BY-SA 3.0 |