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But - is there anything inside these certificates that identify to a browser what the "intended purpose" of a given certificate is, and prevents such a CA from
by 0x0 14y ago
But - is there anything inside these certificates that identify to a browser what the "intended purpose" of a given certificate is, and prevents such a CA from being used for MITM attacks? How would a regular browser such as IE or Safari act when presented with a certificate for "bank.example.com" signed by such a CA?
- tptacek 14y agoYes: the X.509 nameConstraints field, which modern browsers will read to determine which subdomains are acceptable as subjects for certs signed by the CA. Earlier today I thought that nameConstraints was ineffective, but it seems to turn out that the problem is mostly limited to Safari.
- 0x0 14y agoHm ok, I guess that makes it less of a big deal, but it still sits funny with me. I guess all iOS devices are still "vulnerable" to a rogue nameConstrained CA then - assuming they share code with Safari?