I post before about sqlnet.ora with parameter called invited_list , Exclude_list , assume that i want to prevent sysdba to access database without password Simple Way .
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:
kerberos5for Kerberos authentication
cybersafefor Cybersafe authentication
radiusfor RADIUS authentication
dcegssapifor 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.