Information
The SECURE_CONTROL_<listener_name> setting determines the type of control connection the Oracle server requires for remote configuration of the listener.
Rationale:
Listener configuration changes via unencrypted remote connections can result in unauthorized users sniffing control configuration information from the network.
Solution
To remediate this recommendation:
Set the SECURE_CONTROL_<listener_name> for each defined listener in the listener.ora file.
References:
http://docs.oracle.com/database/121/NETRF/listener.htm#NETRF327