SYSDBA and v$pwfile_user

This link contains information about how to check which user has sysdba privilege

http://www.adp-gmbh.ch/ora/admin/password_file.html#adding_user

SQL> select * from v$pwfile_users;

USERNAME SYSDB SYSOP
------------------------------ ----- -----

INTERNAL TRUE TRUE

SYS TRUE TRUE

SQL> grant sysdba to system;

Grant succeeded.

USERNAME SYSDB SYSOP

------------------------------ ----- -----

INTERNAL TRUE TRUE

SYS TRUE TRUE

SYSTEM TRUE FALSE