RESTRICT OPERATING SYSTEM ACCESS
Limit the number of users with operating system access on the Oracle Database
host. Oracle recommends restricting the ability to modify the default file and
directory permissions for the Oracle Database home (installation) directory or its
contents. Even privileged operating system users and the Oracle owner should not
modify these permissions, unless instructed otherwise by Oracle.
Restrict usage of symbolic links on the operating system. When providing a path or
file to the Oracle database, neither the file nor any part of the path should be
modifiable by an un-trusted user. The file and all components of the path should
be owned by the DBA or another trusted operating system account.