Information
The _trace_files_public setting determines whether or not the system's trace file is world readable. This setting should have a value of FALSE to restrict trace file access.
Rationale:
Making the file world readable means anyone can read the instance's trace file, which could contain sensitive information about instance operations.
Solution
To remediate this setting, execute the following SQL statement.
ALTER SYSTEM SET '_trace_files_public' = FALSE SCOPE = SPFILE;
References:
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:4295521746131