Ensures that basic audit features are used. Recommended setting audit_trail to OS as it reduces the likelihood of a Denial of Service attack and it is easier to secure the audit trail. OS is required if the auditor is distinct from the DBA. Level 1, Scorable NOTE: Change ORACLE_HOME to the full path to your organization's Oracle directory. ref: https://benchmarks.cisecurity.org/tools2/oracle/CIS_Oracle_11g_Benchmark_v1.0.1.pdf, pg 33.