Oracle operating system authentication (connect as sysdba) login Method

One way to log on to Oracle is to verify the login mode of the operating system, that is, the OS authentication login mode, which is also available in SQL Server.
Some friends often use connect/As sysdba to log on, but do not know why sysdba permissions are obtained without providing the user name and password. Still think this is not safe?

Oracle can perform OS authentication on common multi-user operating systems. For example, Solaris or windows.
The following describes how to log on with the common Windows operating system as the operating system authentication method. If your machine can use connect/As sysdba to obtain sysdba permissions, your machine will be verified in each of the following processes. If not, follow the steps below to change the permissions, you can also log on in this way.

1. Enter compmgmt. MSC in the command line to enter Computer Management
2. Select local user and group> group
3. Check whether there is a group named ora_dba.
4. Double-click the reorganization to see if there is an administrator user in it.
5. Do you want to log on as an administrator user?
6. Go to the Oracle Installation Directory (that is, $ ORACLE_HOME is generally D: "Oracle)" ora92 "network" Admin and find the sqlnet. ora file to see if sqlnet. authentication_services = (ETS) exists)
7. If these are true, you can log on to Oracle using the operating system authentication (connect/As sysdba) method.

The next question is, if your data is very important and you want to disable this authentication method for the sake of security. So what should we do?
Find the sqlnet. ora file in step 6th and change sqlnet. authentication_services = (ETS) to sqlnet. authentication_services = none. Try again to see if the following results are returned:
Error:
ORA-01031: insufficient privileges
Warning: you are no longer connected to Oracle.

If your machine cannot log on using system authentication, check the above steps to find the cause.