I want to export the configuration details from an existing CSR or Certificate to a config file which I can use with OpenSSL to generate a new CSR.
Background Our CA has changed. For the old one, I submitted a CSR and a list of subjectAltNames and the CA team sorted it out. For the new CA, I have to submit a CSR with the subjectAltNames included. It's a critical time of the year and I can't make a mistake, so I'd rather export the configuration file than recreate it manually, if that's possible. It's for a Windows server. I don't know how the original CSR was created - there's no existing config file. I've exported the private key from the windows key store, for use with OpenSSL. I have the original CSR and the certificate.