一. 官網說明

1.1 Oracle 11gR2 concepts

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1.1.1 Database Auditing

Databaseauditing is the monitoring and recording of selected user database actions. You can use standard auditing to audit SQL statements,privileges, schemas, objects, and network and multitier activity.Alternatively, you can use fine-grained auditingto monitor specific database activities, such as actions on a database table ortimes that activities occur. For example, you can audit a table accessed after9:00 p.m.

Reasons for using auditing include:

（1）Enabling future accountability for current actions

（2）Deterring users (or others, such as intruders) from inappropriateactions based on their accountability

（3）Investigating, monitoring, and recording suspicious activity

（4）Addressing auditing requirements for compliance

1.1.2 Oracle Audit Vault

OracleAudit Vault enables you to consolidate, report, and configure alerts foraudited data. You can consolidate audit data generated by Oracle Database andother relational databases. You can also use Oracle Audit Vault to monitoraudit settings on target databases.

1.2 Oracle 10gR2 concept

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1.2.1 Overview of Database Auditing

Auditingis the monitoring and recording of selected user database actions. It can bebased on individual actions, such as the type of SQL statement run, or oncombinations of factors that can include name, application, time, and so on.Security policies can cause auditing when specified elements in an Oracledatabase are accessed or altered, including content.

Auditing is generally used to:

（1）Enable future accountability for current actions taken in aparticular schema, table, or row, or affecting specific content

（2）Investigate suspicious activity. For example, if an unauthorizeduser is deleting data from tables, then the security administrator could auditall connections to the database and all successful and unsuccessful deletionsof rows from all tables in the database.

（3）Monitor and gather data about specific database activities. Forexample, the database administrator can gather statistics about which tablesare being updated, how many logical I/Os are performed, or how many concurrentusers connect at peak times.

Youcan use Enterprise Manager to view and configure audit-related initializationparameters and administer audited objects for statement auditing and schemaobject auditing. For example, Enterprise Manager shows the properties forcurrent audited statements, privileges, and objects. You can view theproperties of each object, and you can search audited objects by theirproperties. You can also turn on and turn off auditing on objects, statements,and privileges.

1.2.2 Types and Records of Auditing

Oracle allows audit options to be focused or broad. You can audit:

（1）Successful statement executions, unsuccessful statement executions,or both

（2）Statement executions once in each user session or once every timethe statement is run

（3）Activities of all users or of a specific user

Oracle auditing enablesthe use of several different mechanisms, with the following features:

Table 20-1 Types of Auditing

Type of Auditing	Meaning/Description
Statement auditing	Audits SQL statements by type of statement, not by the specific schema objects on which they operate. Typically broad, statement auditing audits the use of several types of related actions for each option. For example, AUDIT TABLE tracks several DDL statements regardless of the table on which they are issued. You can also set statement auditing to audit selected users or every user in the database.
Privilege auditing	Audits the use of powerful system privileges enabling corresponding actions, such as AUDIT CREATE TABLE. Privilege auditing is more focused than statement auditing because it audits only the use of the target privilege. You can set privilege auditing to audit a selected user or every user in the database.
Schema object auditing	Audits specific statements on a particular schema object, such as AUDIT SELECT ON employees. Schema object auditing is very focused, auditing only a specific statement on a specific schema object. Schema object auditing always applies to all users of the database.
Fine-grained auditing	Audits data access and actions based on content. Using DBMS_FGA, the security administrator creates an audit policy on the target table. If any rows returned from a DML statement block match the audit condition, then an audit event entry is inserted into the audit trail.

1.2.3Audit Records and the Audit Trails

Audit records includeinformation such as the operation that was audited, the user performing theoperation, and the date and time of the operation. Audit records can be storedin either a data dictionary table, called the databaseaudit trail, or in operating system files, calledan operating system audit trail.

1.2.3.1 DatabaseAudit Trail

The database audit trail is a single table named SYS.AUD$ in the SYS schema ofeach Oracle database's data dictionary. Several predefined views are providedto help you use the information in this table.

Audit trail records can contain different types ofinformation, depending on the events audited and the auditing options set.The following information is always included in each audit trail record, if theinformation is meaningful to the particular audit action:

（1）User name

（2）Instance number

（3）Process identifier

（4）Session identifier

（5）Terminal identifier

（6）Name of the schema object accessed

（7）Operation performed or attempted

（8）Completion code of the operation

（9）Date and time stamp

（10）System privileges used

1.2.3.2 Auditing in a DistributedDatabase

Auditing is siteautonomous. An instance audits only the statements issued by directly connectedusers. A local Oracle node cannot audit actions that take place in a remotedatabase. Because remote connections are established through the user accountof a database link, statements issued through the database link's connectionare audited by the remote Oracle node.

1.2.3.3 OperatingSystem Audit Trail

Oracleallows audit trail records to be directed to an operating system audit trail ifthe operating system makes such an audit trail available to Oracle. If not, then audit records are written to a file outside thedatabase, with a format similar to other Oracle trace files.

Oracleallows certain actions that are always audited to continue, even when theoperating system audit trail (or the operating system file containing auditrecords) is unable to record the audit record. The usual cause of this is thatthe operating system audit trail or the file system is full and unable toaccept new records.

Systemadministrators configuring operating system auditing should ensure that theaudit trail or the file system does not fill completely. Most operating systemsprovide administrators with sufficient information and warning to ensure thisdoes not occur. Note, however, that configuring auditing to use the databaseaudit trail removes this vulnerability, because the Oracle database serverprevents audited events from occurring if the audit trail is unable to acceptthe database audit record for the statement.

1.2.3.4 Operating System AuditRecords

Theoperating system audit trail is encoded, but it is decoded in data dictionaryfiles and error messages.

（1）Action code describes the operation performed or attempted. The AUDIT_ACTIONS data dictionary table describes thesecodes.

（2）Privileges used describes any system privileges used to perform theoperation. The SYSTEM_PRIVILEGE_MAP table describesall of these codes.

（3）Completion code describes the result of the attempted operation.Successful operations return a value of zero, and unsuccessful operationsreturn the Oracle error code describing why the operation was unsuccessful.

1.2.3.5 RecordsAlways in the Operating System Audit Trail

Somedatabase-related actions are always recorded into the operating system audittrail regardless of whether database auditing isenabled:

（1）At instance startup, anaudit record is generated that details the operating system user starting theinstance, the user's terminal identifier, the date and time stamp, and whetherdatabase auditing was enabled or disabled. Thisinformation is recorded into the operating system audit trail, becausethe database audit trail is not available until after startup has successfullycompleted. Recording the state of database auditing at startup also acts as anauditing flag, inhibiting an administrator from performing unaudited actions byrestarting a database with database auditing disabled.

（2）At instance shutdown, anaudit record is generated that details the operating system user shutting downthe instance, the user's terminal identifier, the date and time stamp.

（3）During connections with administrator privileges,an audit record is generated that details the operating system user connectingto Oracle with administrator privileges. This recordprovides accountability regarding users connected with administratorprivileges.

Onoperating systems that do not make an audit trail accessible to Oracle, theseaudit trail records are placed in an Oracle audit trail file in the samedirectory as background process trace files.

1.2.3.6 When Are Audit RecordsCreated?

Anyauthorized database user can set his own audit options at any time, but the recording of audit information is enabled or disabled bythe security administrator.

When auditing is enabled in the database, an audit record isgenerated during the execute phase of statement execution.

SQL statements inside PL/SQL programunits are individually audited, as necessary, when the program unit is run.

The generation and insertion of an audittrail record is independent of a user's transaction being committed. That is, even if a user's transaction is rolled back, theaudit trail record remains committed.

Statement and privilegeaudit options in effect at the time a database user connects to the databaseremain in effect for the duration of the session. Setting or changing statementor privilege audit options in a session does not cause effects in that session.The modified statement or privilege audit options take effect only when thecurrent session is ended and a new session is created. In contrast, changes toschema object audit options become effective for current sessions immediately.

Operations by the SYS user and by users connected through SYSDBAor SYSOPER can be fully audited with the AUDIT_SYS_OPERATIONS initializationparameter. Successful SQL statements from SYS are auditedindiscriminately. The audit records for sessions established by the user SYS orconnections with administrative privileges are sent to an operating systemlocation. Sending them to a location separate from the usual database audittrail in the SYS schema provides for greater auditing security.

二. Audit說明

2.1 審計

審計（Audit)用於監視使用者所執行的資料庫操作，審計記錄可存在資料字典表（稱為審計記錄:儲存在system表空間中的 SYS.AUD$表中，可通過檢視dba_audit_trail檢視）或作業系統審計記錄中(預設位置為$ORACLE_BASE/admin/$ORACLE_SID/adump/).。預設情況下審計是沒有開啟的。

當資料庫的審計是使能的，在語句執行階段產生審計記錄。審計記錄包含有審計的操作、使用者執行的操作、操作的日期和時間等資訊。

不管你是否開啟資料庫的審計功能，以下這些作業系統會強制記錄：用管理員許可權連線Instance；啟動資料庫；關閉資料庫。

2.1.1 Oracle審計功能

審計是對選定的使用者動作的監控和記錄，通常用於：

審查可疑的活動。例如：資料被非授權使用者所刪除，此時安全管理員可決定對該資料庫的所有連線進行審計，以及對資料庫的所有表的成功地或不成功地刪除進行審計。

監視和收集關於指定資料庫活動的資料。例如：DBA可收集哪些被修改、執行了多少次邏輯的I/O等統計資料。

2.1.2 ORACLE所允許的審計選擇限於下列方面：

審計語句的成功執行、不成功執行，或者其兩者。

對每一使用者會話審計語句執行一次或者對語句每次執行審計一次。

對全部使用者或指定使用者的活動的審計。

2.1.3 審計相關的表安裝

SQLPLUS> connect / AS SYSDBA

SQLPLUS> select * from sys.aud$; --沒有記錄返回

SQLPLUS> select * from dba_audit_trail; - 沒有記錄返回

如果做上述查詢的時候發現表不存在，說明審計相關的表還沒有安裝，需要安裝。

SQLPLUS> connect / as sysdba

SQLPLUS> @$ORACLE_HOME/rdbms/admin/cataudit.sql

審計表安裝在SYSTEM表空間。所以要確保SYSTEM表空間又足夠的空間存放審計資訊。

安裝後要重啟資料庫

2.1.4 將審計相關的表移動到其他表空間

由於AUD$表等審計相關的表存放在SYSTEM表空間，因此為了不影響系統的效能，保護SYSTEM表空間，最好把AUD$移動到其他的表空間上。可以使用下面的語句來進行移動：

sql>connect / as sysdba;

sql>alter table aud$ move tablespace<new tablespace>;

sql>alter index I_aud1 rebuild onlinetablespace <new tablespace>;

SQL> alter table audit$ move tablespace<new tablespace>;

SQL> alter index i_audit rebuild onlinetablespace <new tablespace>;

SQL> alter table audit_actions movetablespace <new tablespace>;

SQL> alter index i_audit_actions rebuildonline tablespace <new tablespace>;

2.1.5 truncate 或者 delete sys.aud$ 表

在delete 之前，可以先把aud$表exp備份一下，注意，不要直接exp，先建立一張臨時表，然後將臨時表exp。

sql>createtable audit_record tablespace users as select * from sys.aud$;然後exp：

exptables=AUDIT_RECORD file=audit_record.dmp

最後delete 資料：

sql>delete from sys.aud$;

或者刪除指定表的審計：

sql>delete from sys.aud$ whereobj$name='&table_nmae';注意，delete 不會釋放system表空間。可以使用truncate table：

sql>truncate table sys.aud$

2.2 和審計相關的兩個主要引數

2.2.1 Audit_sys_operations

AUDIT_SYS_OPERATIONSenables or disables the auditing of top-level operations, which are SQL statementsdirectly issued by users when connecting with SYSDBA or SYSOPER privileges.(SQL statements run from within PL/SQL procedures or functions are notconsidered top-level.) The audit records are written to the operating system'saudit trail. The audit records will be written in XML format if the AUDIT_TRAILinitialization parameter is set to xml or xml, extended.

OnUNIX platforms, if the AUDIT_SYSLOG_LEVEL parameter has also been set, then itoverrides the AUDIT_TRAIL parameter and SYS audit records are written to thesystem audit log using the SYSLOG utility.

預設為false，當設定為true時，所有sys使用者（包括以sysdba, sysoper身份登入的使用者）的操作都會被記錄，audit trail不會寫在aud$表中，這個很好理解，如果資料庫還未啟動aud$不可用，那麼像conn /as sysdba這樣的連線資訊，只能記錄在其它地方。如果是windows平臺，audti trail會記錄在windows的事件管理中，如果是linux/unix平臺則會記錄在audit_file_dest引數指定的檔案中。

SQL> show parameteraudit_file_dest

NAME TYPE VALUE

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

audit_file_dest string /u01/app/oracle/admin/dave2/adump

2.2.2 Audit_trail

AUDIT_TRAIL enables or disables databaseauditing.

Values:

（1）none：Disables standard auditing. This value is thedefault if the AUDIT_TRAIL parameter was not set in the initializationparameter file or if you created the database using a method other thanDatabase Configuration Assistant. If you created the database using DatabaseConfiguration Assistant, then the default is db.

（2）os：Directs all audit records to an operating system file. Oraclerecommends that you use the os setting, particularly if you are using anultra-secure database configuration.

（3）db：Directs audit records to the database audit trail (the SYS.AUD$table), except for records that are always written to the operating systemaudit trail. Use this setting for a general database for manageability.

If the database was started in read-onlymode with AUDIT_TRAIL set to db, then Oracle Database internally sets AUDIT_TRAILto os. Check the alert log for details.

（4）db, extended：Performs all actions of AUDIT_TRAIL=db,and also populates the SQL bind and SQL text CLOB-type columns of the SYS.AUD$table, when available. These two columns are populated only when this parameteris specified.

If the database was started in read-onlymode with AUDIT_TRAIL set to db, extended, then Oracle Database internally setsAUDIT_TRAIL to os. Check the alert log for details.

（5）xml：Writes to the operating system audit record file in XML format.Records all elements of the AuditRecord node except Sql_Text and Sql_Bind tothe operating system XML audit file.

（6）xml, extended：Performs all actions of AUDIT_TRAIL=xml,and populates the SQL bind and SQL text CLOB-type columns of the SYS.AUD$table, wherever possible. These columns are populated only when this parameteris specified.

Youcan use the SQL AUDIT statement to set auditing options regardless of thesetting of this parameter.

None：是預設值，不做審計；

DB：將audit trail 記錄在資料庫的審計相關表中，如aud$，審計的結果只有連線資訊；

DB,Extended：這樣審計結果裡面除了連線資訊還包含了當時執行的具體語句；

OS：將audit trail 記錄在作業系統檔案中，檔名由audit_file_dest引數指定；

XML：10g裡新增的。

注：這兩個引數是static引數，需要重新啟動資料庫才能生效。

2.3審計級別

當開啟審計功能後，可在三個級別對資料庫進行審計：Statement(語句)、Privilege（許可權）、object（物件）。

2.3.1 Statement

語句審計，對某種型別的SQL語句審計，不指定結構或物件。比如audit table 會審計資料庫中所有的create table,droptable,truncate table語句，alter session by cmy會審計cmy使用者所有的資料庫連線。

2.3.2 Privilege

許可權審計，當用戶使用了該許可權則被審計，如執行grant selectany table to a，當執行了auditselect any table語句後，當用戶a 訪問了使用者b的表時（如select * from b.t）會用到select any table許可權，故會被審計。注意使用者是自己表的所有者，所以使用者訪問自己的表不會被審計。

2.3.3 Object

物件審計，對一特殊模式物件上的指定語句的審計. 如審計on關鍵字指定物件的相關操作，如aduitalter,delete,drop,insert on cmy.t by scott; 這裡會對cmy使用者的t表進行審計，但同時使用了by子句，所以只會對scott使用者發起的操作進行審計。

注意：Oracle沒有提供對schema中所有物件的審計功能，只能一個一個物件審計，對於後面建立的物件，Oracle則提供on default子句來實現自動審計，比如執行audit drop on defaultby access;後，對於隨後建立的物件的drop操作都會審計。但這個default會對之後建立的所有資料庫物件有效，似乎沒辦法指定只對某個使用者建立的物件有效，想比 trigger可以對schema的DDL進行“審計”，這個功能稍顯不足。

2.4審計的一些其他選項

2.4.1 by access / by session

by access 每一個被審計的操作都會生成一條audit trail。

by session 一個會話裡面同類型的操作只會生成一條audit trail，預設為by session。

Oracle Audit 審計 說明