Setting "SQLNET.AUTHENTICATION_SERVICES" parameter to "NONE" in sqlnet.ora file will make it not possible to connect to the database without a password as sysdba. (sqlplus / as sysdba)

This parameter may also have the values : NTS for Windows NT native authentication, ALL for all authentication methods.

Authentication Methods Available with Oracle Advanced Security:

  • kerberos5 for Kerberos authentication

  • cybersafe for Cybersafe authentication

  • radius for RADIUS authentication

  • dcegssapi for DCE GSSAPI authentication

If authentication has been installed, it is recommended that this parameter be set to either none or to one of the authentication methods.