Add the abillity to specify a passphrase for private key

[jakauppila]

Per kibana.yml, you can specify the cert and key locations

# SSL for outgoing requests from the Kibana Server (PEM formatted)
#ssl_key_file: /path/to/your/server.key
#ssl_cert_file: /path/to/your/server.crt

I would like to see the ability to specify the passphrase for the key so that I can store it encrypted on disk.

[simianhacker]

Per our discussion on https://discuss.elastic.co/t/configuring-kibana-with-ssl-how-to-define-passphrase-for-the-private-key/2464:

To help us better understand your concerns with using a passphraseless key, what would you prefer for solution?

For systems that need to be automatically started without human intervention the options I know about are:

• Passphraseless SSL Key
• Store passphrase in config and pass as an argument to TLS server (just as insecure as first scenario)
• Prompt user for passphrase (doesn't scale and requires human intervention or requires an expect script with passphrase; which is also insecure)

Thoughts?

[jakauppila]

There really is no good solution in terms of actually securing the passphrase as you have mentioned.

This was more stemming from other systems that I support maintain that functionality, such as Tomcat:

https://tomcat.apache.org/tomcat-7.0-doc/ssl-howto.html#Edit_the_Tomcat_Configuration_File

<!-- Define a SSL Coyote HTTP/1.1 Connector on port 8443 -->
<Connector
           protocol="org.apache.coyote.http11.Http11NioProtocol"
           port="8443" maxThreads="200"
           scheme="https" secure="true" SSLEnabled="true"
           keystoreFile="${user.home}/.keystore" keystorePass="changeit"
           clientAuth="false" sslProtocol="TLS"/>

But yes, if an attacker has already compromised the system and has file-level access to the certificate, they could likely get at the config file as well.

[kobelb]

This has been resolved by #9823