Auditing tracks changes that users make in the database.
Except where noted, this part describes how to use pure unified auditing, in which all audit records are centralized in one place.
24.1 What Is Auditing?
Auditing is the monitoring and recording of configured database actions, from both database users and nondatabase users.
"Nondatabase users" refers to application users who are recognized in the database using the
CLIENT_IDENTIFIER attribute. To audit this type of user, you can use a unified audit policy condition, a fine-grained audit policy, or Oracle Database Real Application Security.
You can base auditing on individual actions, such as the type of SQL statement executed, or on combinations of data that can include the user name, application, time, and so on.
You can configure auditing for both successful and failed activities, and include or exclude specific users from the audit. In a multitenant environment, you can audit individual actions of the pluggable database (PDB) or individual actions in the entire multitenant container database (CDB). In addition to auditing the standard activities the database provides, auditing can include activities from Oracle Database Real Application Security, Oracle Recovery Manager, Oracle Data Pump, Oracle Data Mining, Oracle Database Vault, Oracle Label Security, and Oracle SQL*Loader direct path events.
Auditing is enabled by default. All audit records are written to the unified audit trail in a uniform format and are made available through the
UNIFIED_AUDIT_TRAIL view. These records reside in the
AUDSYS schema. The audit records are stored in the
SYSAUX tablespace by default. Oracle recommends that you configure a different tablespace for the unified audit trail. Be aware that for most Oracle Database editions except for Enterprise Edition, you can only associate the tablespace for unified auditing once. You should perform this association before you generate any audit records for the unified audit trail. After you have associated the tablespace, you cannot modify it because partitioning is only supported on Enterprise Edition.
You can configure auditing by using any of the following methods:
Group audit settings into one unified audit policy. You can create one or more unified audit policies that define all the audit settings that your database needs. Auditing Activities with Unified Audit Policies and the AUDIT Statement describes how to accomplish this.
Use one of the default unified audit policies. Oracle Database provides predefined unified audit policies that encompass the standard audit settings that most regulatory agencies require. See Auditing Activities with the Predefined Unified Audit Policies.
Create fine-grained audit policies. You can create fine-grained audit policies that capture data such as the time an action occurred. See Auditing Specific Activities with Fine-Grained Auditing.
Oracle recommends that you audit your databases. Auditing is an effective method of enforcing strong internal controls so that your site can meet its regulatory compliance requirements, as defined in the Sarbanes-Oxley Act. This enables you to monitor business operations, and find any activities that may deviate from company policy. Doing so translates into tightly controlled access to your database and the application software, ensuring that patches are applied on schedule and preventing ad hoc changes. By creating effective audit policies, you can generate an audit record for audit and compliance personnel. Be selective with auditing and ensure that it meets your business compliance needs.
24.2 Why Is Auditing Used?
You typically use auditing to monitor user activity.
Auditing can be used to accomplish the following:
Enable accountability for actions. These include actions taken in a particular schema, table, or row, or affecting specific content.
Deter users (or others, such as intruders) from inappropriate actions based on their accountability.
Investigate suspicious activity. For example, if a user is deleting data from tables, then a security administrator can audit all connections to the database and all successful and unsuccessful deletions of rows from all tables in the database.
Notify an auditor of the actions of an unauthorized user. For example, an unauthorized user could be changing or deleting data, or the user has more privileges than expected, which can lead to reassessing user authorizations.
Monitor and gather data about specific database activities. For example, the database administrator can gather statistics about which tables are being updated, how many logical I/Os are performed, or how many concurrent users connect at peak times.
Detect problems with an authorization or access control implementation. For example, you can create audit policies that you expect will never generate an audit record because the data is protected in other ways. However, if these policies generate audit records, then you will know the other security controls are not properly implemented.
Address auditing requirements for compliance. Regulations such as the following have common auditing-related requirements:
Health Insurance Portability and Accountability Act (HIPAA)
International Convergence of Capital Measurement and Capital Standards: a Revised Framework (Basel II)
Japan Privacy Law
European Union Directive on Privacy and Electronic Communications
24.3 Best Practices for Auditing
You should follow best practices guidelines for auditing.
As a general rule, design your auditing strategy to collect the amount of information that you need to meet compliance requirements, but focus on activities that cause the greatest security concerns. For example, auditing every table in the database is not practical, but auditing tables with columns that contain sensitive data, such as salaries, is. With both unified and fine-grained auditing, there are mechanisms you can use to design audit policies that focus on specific activities to audit.
Periodically archive and purge the audit trail data. See Purging Audit Trail Records for more information.
24.4 What Is Unified Auditing?
In unified auditing, the unified audit trail captures audit information from a variety of sources.
Unified auditing enables you to capture audit records from the following sources:
Audit records (including
SYSaudit records) from unified audit policies and
Fine-grained audit records from the
Oracle Database Real Application Security audit records
Oracle Recovery Manager audit records
Oracle Database Vault audit records
Oracle Label Security audit records
Oracle Data Mining records
Oracle Data Pump
Oracle SQL*Loader Direct Load
The unified audit trail, which resides in a read-only table in the
AUDSYS schema in the
SYSAUX tablespace, makes this information available in a uniform format in the
UNIFIED_AUDIT_TRAIL data dictionary view, and is available in both single-instance and Oracle Database Real Application Clusters environments. In addition to the user
SYS, users who have been granted the
AUDIT_VIEWER roles can query these views. If your users only need to query the views but not create audit policies, then grant them the
When the database is writeable, audit records are written to the unified audit trail. If the database is not writable, then audit records are written to new format operating system files in the
Oracle Database Reference for detailed information about the
UNIFIED_AUDIT_TRAIL data dictionary view
24.5 Benefits of the Unified Audit Trail
The benefits of a unified audit trail are many.
After unified auditing is enabled, it does not depend on the initialization parameters that were used in previous releases. See Table G-1 for a list of these initialization parameters.
The audit records, including records from the
SYSaudit trail, for all the audited components of your Oracle Database installation are placed in one location and in one format, rather than your having to look in different places to find audit trails in varying formats. This consolidated view enables auditors to co-relate audit information from different components. For example, if an error occurred during an
INSERTstatement, standard auditing can indicate the error number and the SQL that was executed. Oracle Database Vault-specific information can indicate whether this error happened because of a command rule violation or realm violation. Note that there will be two audit records with a distinct
AUDIT_TYPE. With this unification in place,
SYSaudit records appear with
The management and security of the audit trail is also improved by having it in single audit trail.
Overall auditing performance is greatly improved. By default, the audit records are automatically written to an internal relational table in the
You can create named audit policies that enable you to audit the supported components listed at the beginning of this section, as well as
SYSadministrative users. Furthermore, you can build conditions and exclusions into your policies.
If you are using an Oracle Audit Vault and Database Firewall environment, then the unified audit trail greatly facilitates the collection of audit data, because all of this data will come from one location.
24.6 Checking if Your Database Has Migrated to Unified Auditing
V$OPTION dynamic view indicates if your database has been migrated to unified auditing.
VALUEcolumn of the
V$OPTIONdynamic view as follows, entering
Unified Auditingin the case shown:
SELECT VALUE FROM V$OPTION WHERE PARAMETER = 'Unified Auditing'; PARAMETER VALUE ---------------- ---------- Unified Auditing TRUE
This output shows that unified auditing is enabled. If unified auditing has not been enabled, then the output is
24.7 Mixed Mode Auditing
Mixed mode auditing is the default auditing in a newly installed database.
24.7.1 About Mixed Mode Auditing
Mixed mode auditing enables both traditional (that is, the audit facility from releases earlier than release 12c) and the new audit facilities (unified auditing).
When you create a new database, by default the database uses mixed mode auditing.
You can enable the database in either of these two modes: the mixed mode auditing or pure unified auditing mode. Even though the features of unified auditing are enabled in both these modes, there are differences between them. In mixed mode, you can use the new unified audit facility alongside the traditional auditing facility. In pure unified auditing, you only use the unified audit facility.
Table 24-1 summarizes the features of these two modes and how you enable them.
Table 24-1 Differences Between Mixed Mode Audting and Pure Unified Auditing
|Mode||Features||How to Enable|
Mixed mode auditing
Has both traditional and unified auditing
Enable any unified audit policy. There is no need to restart the database.
Pure unified auditing
Has only unified auditing
Mixed mode is intended to introduce unified auditing, so that you can have a feel of how it works and what its nuances and benefits are. Mixed mode enables you to migrate your existing applications and scripts to use unified auditing. Once you have decided to use pure unified auditing, you can relink the
oracle binary with the unified audit option turned on and thereby enable it as the one and only audit facility the Oracle database runs. If you decide to revert back to mixed mode, you can.
As in previous releases, the traditional audit facility is driven by the
AUDIT_TRAIL initialization parameter. Only for mixed mode auditing, you should set this parameter to the appropriate traditional audit trail. This traditional audit trail will then be populated with audit records, along with the unified audit trail.
When you upgrade your database to the current release, traditional auditing is preserved, and the new audit records are written to the traditional audit trail. After you complete the migration, the audit records from the previous release are still available in those audit trails. You then can archive and purge these older audit trails by using the
DBMS_AUDIT_MGMT PL/SQL procedures, based on your enterprise retention policies.
How the Unified Auditing Migration Affects Individual Audit Features, for a comparison of the features available in the pre-migrated and post-migrated auditing environments
Oracle Database Upgrade Guide for information about migrating your databases to unified auditing, and for references to the documentation you should use if you choose not to migrate
24.7.2 Enablement of Unified Auditing
By default, Oracle Database uses mixed mode auditing, supporting both unified audit and traditional audit.
When you are ready to migrate to pure unified audit mode (which improves audit performance), link the
oracle binary with
uniaud_on, and then restart the database, as described in Oracle Database Upgrade Guide.
24.7.3 How Database Creation Determines the Type of Auditing You Have Enabled
Unified auditing uses the
$ORACLE_BASE/audit directory as the location for the new format operating system files.
For newly created databases, mixed mode auditing is enabled by default through the predefined policy
To start using unified auditing, you must enable at least one unified audit policy, and to stop using it, disable all unified audit policies.
24.7.4 Capabilities of Mixed Mode Auditing
Mixed mode auditing provides several capabilities.
These capabilities are as follows:
It enables the use of all existing auditing initialization parameters:
It writes mandatory audit records only to the traditional audit trails.
It bases standard audit records on the standard audit configuration, and writes these records to the audit trail designated by the
However, be aware that standard audit trail records are also generated based on unified audit policies and only these audit records are written to the unified audit trail. The standard audit records generated as a result of unified audit policies follow the semantics of unified audit policy enablement.
Administrative user sessions generate
SYSaudit records. These records are written if the
AUDIT_SYS_OPERATIONSinitialization parameter is set to
TRUE. This process writes the records only to the traditional audit trails. However, when unified audit policies are enabled for administrative users, these unified audit records are also written to unified audit trail.
The format of the audit records that are written to traditional audit trails remains the same as in Oracle Database 11g Release 2.
By default, Oracle Database immediately writes unified audit records to an internal relational table in the
The performance cost of writing an audit record is equivalent to the sum of the times required for generating and writing an audit record to the traditional audit trail and the unified audit trail.
Mixed mode auditing provides a glance of the unified audit mode features. Oracle recommends that you migrate to unified audit mode once you are comfortable with the new style of audit policies and audit trail.
24.8 Who Can Perform Auditing?
Oracle provides two roles for users who perform auditing:
To perform any kind of auditing, you must be granted the
AUDIT_ADMIN role. An auditor can view audit data after being granted the
The privileges that these roles provide are as follows:
AUDIT_ADMIN role. This role enables you to create unified and fine-grained audit policies, use the
NOAUDITSQL statements, view audit data, and manage the audit trail administration. Grant this role only to trusted users.
AUDIT_VIEWER role. This role enables users to view and analyze audit data. It provides the
EXECUTEprivilege on the
DBMS_AUDIT_UTILPL/SQL package. The kind of user who needs this role is typically an external auditor.
In previous releases, users were allowed to add and remove audit configuration to objects in their own schemas without any additional privileges. This ability is no longer allowed.
24.9 Unified Auditing in a Multitenant Environment
You can apply audit settings to individual PDBs or to the CDB, depending on the type of policy.
Each PDB, including the root, has its own unified audit trail.
Unified audit policies created with the CREATE AUDIT POLICY and AUDIT statements: You can create policies for both the root and individual PDBs.
Audit records written to the syslog: On UNIX platforms, you can set the
UNIFIED_AUDIT_COMMON_SYSTEMLOGinitialization parameter in the CDB root to enable certain unified audit trail columns to be written to SYSLOG. On both Windows and UNIX, you can set the
UNIFIED_AUDIT_SYSTEMLOGparameter in both the root and PDB level.
Fine-grained audit policies: You can create policies for individual PDBs only, not the root.
Purging the audit trail: You can perform purge operations for both the root and individual PDBs.