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CREATE SERVER AUDIT (Transact-SQL)

  • Άρθρο

Applies to: SQL Server Azure SQL Managed Instance

Creates a server audit object using SQL Server Audit. For more information, see SQL Server Audit (Database Engine).

Transact-SQL syntax conventions

Syntax

CREATE SERVER AUDIT audit_name
{
    TO { [ FILE (<file_options> [ , ...n ] ) ] | APPLICATION_LOG | SECURITY_LOG | URL | EXTERNAL_MONITOR }
    [ WITH ( <audit_options> [ , ...n ] ) ]
    [ WHERE <predicate_expression> ]
}
[ ; ]

<file_options>::=
{
    FILEPATH = 'os_file_path'
    [ , MAXSIZE = { max_size { MB | GB | TB } | UNLIMITED } ]
    [ , { MAX_ROLLOVER_FILES = { integer | UNLIMITED } } | { MAX_FILES = integer } ]
    [ , RESERVE_DISK_SPACE = { ON | OFF } ]
}

<audit_options> ::=
{
    [ QUEUE_DELAY = integer ]
    [ , ON_FAILURE = { CONTINUE | SHUTDOWN | FAIL_OPERATION } ]
    [ , AUDIT_GUID = uniqueidentifier ]
    [ , OPERATOR_AUDIT = { ON | OFF } ]
}

<predicate_expression> ::=
{
    [ NOT ] <predicate_factor>
    [ { AND | OR } [ NOT ] { <predicate_factor> } ]
    [ , ...n ]
}

<predicate_factor>::=
    event_field_name { = | < > | != | > | >= | < | <= | LIKE } { number | 'string' }

Arguments

TO { FILE | APPLICATION_LOG | SECURITY_LOG | URL | EXTERNAL_MONITOR }

Determines the location of the audit target. The options are a binary file, The Windows Application log, or the Windows Security log. SQL Server can't write to the Windows Security log without configuring extra settings in Windows. For more information, see Write SQL Server Audit events to the Security log.

The URL target isn't supported for SQL Server.

Important

In Azure SQL Managed Instance, SQL Audit works at the server level. Locations can only be URL or EXTERNAL_MONITOR.

FILEPATH = 'os_file_path'

The path of the audit log. The file name is generated based on the audit name and audit GUID. If this path is invalid, the audit isn't created.

FILEPATH target isn't supported for Azure SQL Managed Instance. You need to use PATH instead.

MAXSIZE = max_size

Specifies the maximum size to which the audit file can grow. The max_size value must be an integer followed by MB, GB, TB, or UNLIMITED. The minimum size that you can specify for max_size is 2 MB and the maximum is 2,147,483,647 TB. When UNLIMITED is specified, the file grows until the disk is full. (0 also indicates UNLIMITED.) Specifying a value lower than 2 MB raises the error MSG_MAXSIZE_TOO_SMALL. The default value is UNLIMITED.

MAXSIZE target isn't supported for Azure SQL Managed Instance.

MAX_ROLLOVER_FILES = { integer | UNLIMITED }

Specifies the maximum number of files to retain in the file system in addition to the current file. The MAX_ROLLOVER_FILES value must be an integer or UNLIMITED. The default value is UNLIMITED. This parameter is evaluated whenever the audit restarts (which can happen when the instance of the Database Engine restarts or when the audit is turned off and then on again) or when a new file is needed because the MAXSIZE is reached. When MAX_ROLLOVER_FILES is evaluated, if the number of files exceeds the MAX_ROLLOVER_FILES setting, the oldest file is deleted. As a result, when the setting of MAX_ROLLOVER_FILES is 0 a new file is created each time the MAX_ROLLOVER_FILES setting is evaluated. Only one file is automatically deleted when MAX_ROLLOVER_FILES setting is evaluated, so when the value of MAX_ROLLOVER_FILES is decreased, the number of files doesn't shrink unless old files are manually deleted. The maximum number of files that can be specified is 2,147,483,647.

MAX_ROLLOVER_FILES isn't supported for Azure SQL Managed Instance.

MAX_FILES = integer

Specifies the maximum number of audit files that can be created. Doesn't roll over to the first file when the limit is reached. When the MAX_FILES limit is reached, any action that causes more audit events to be generated, fails with an error.

RESERVE_DISK_SPACE = { ON | OFF }

This option preallocates the file on the disk to the MAXSIZE value. It applies only if MAXSIZE isn't equal to UNLIMITED. The default value is OFF.

RESERVE_DISK_SPACE target isn't supported for Azure SQL Managed Instance.

QUEUE_DELAY = integer

Determines the time, in milliseconds, that can elapse before audit actions are forced to be processed. A value of 0 indicates synchronous delivery. The minimum settable query delay value is 1000 (1 second), which is the default. The maximum is 2147483647 (2,147,483.647 seconds or 24 days, 20 hours, 31 minutes, 23.647 seconds). Specifying an invalid number raises the MSG_INVALID_QUEUE_DELAY error.

ON_FAILURE = { CONTINUE | SHUTDOWN | FAIL_OPERATION }

Indicates whether the instance writing to the target should fail, continue, or stop SQL Server if the target can't write to the audit log. The default value is CONTINUE.

CONTINUE

SQL Server operations continue. Audit records aren't retained. The audit continues to attempt to log events and resumes if the failure condition is resolved. Selecting the continue option can allow unaudited activity, which could violate your security policies. Use this option, when continuing operation of the Database Engine is more important than maintaining a complete audit.

SHUTDOWN

Forces the instance of SQL Server to shut down, if SQL Server fails to write data to the audit target for any reason. The login executing the CREATE SERVER AUDIT statement must have the SHUTDOWN permission within SQL Server. The shutdown behavior persists even if the SHUTDOWN permission is later revoked from the executing login. If the user doesn't have this permission, then the statement fails and the audit isn't created. Use the option when an audit failure could compromise the security or integrity of the system. For more information, see SHUTDOWN.

FAIL_OPERATION

Database actions fail if they cause audited events. Actions, which don't cause audited events can continue, but no audited events can occur. The audit continues to attempt to log events and resumes if the failure condition is resolved. Use this option when maintaining a complete audit is more important than full access to the Database Engine.

AUDIT_GUID = uniqueidentifier

To support scenarios such as database mirroring, an audit needs a specific GUID that matches the GUID found in the mirrored database. The GUID can't be modified after the audit is created.

OPERATOR_AUDIT

Applies to: Azure SQL Managed Instance only.

Indicates whether auditing captures Microsoft support engineer operations when they need to access your server during a support request.

predicate_expression

Specifies the predicate expression used to determine if an event should be processed or not. Predicate expressions are limited to a length of 3,000 characters, which limits string arguments.

event_field_name

The name of the event field that identifies the predicate source. Audit fields are described in sys.fn_get_audit_file. All fields can be filtered except file_name, audit_file_offset, and event_time.

Note

While the action_id and class_type fields are of type varchar in sys.fn_get_audit_file, they can only be used with numbers when they are a predicate source for filtering. To get the list of values to be used with class_type, execute the following query:

SELECT spt.[name], spt.[number]
FROM   [master].[dbo].[spt_values] spt
WHERE spt.[type] = N'EOD'
ORDER BY spt.[name];

number

Any numeric type including decimal. Limitations are the lack of available physical memory or a number that is too large to be represented as a 64-bit integer.

'string'

Either an ANSI or Unicode string as required by the predicate compare. No implicit string type conversion is performed for the predicate compare functions. Passing the wrong type results in an error.

Remarks

When a server audit is created, it's in a disabled state.

The CREATE SERVER AUDIT statement is in a transaction's scope. If the transaction is rolled back, the statement is also rolled back.

Permissions

To create, alter, or drop a server audit, principals require the ALTER ANY SERVER AUDIT or the CONTROL SERVER permission.

When you're saving audit information to a file, to help prevent tampering, restrict access to the file location.

Examples

A. Create a server audit with a file target

The following example creates a server audit called HIPAA_Audit with a binary file as the target and no options.

CREATE SERVER AUDIT HIPAA_Audit TO FILE (
    FILEPATH = '\\SQLPROD_1\Audit\'
);

B. Create a server audit with a Windows Application log target with options

The following example creates a server audit called HIPAA_Audit with the target set for the Windows Application log. The queue is written every second and shuts down the SQL Server engine on failure.

CREATE SERVER AUDIT HIPAA_Audit TO APPLICATION_LOG
WITH (QUEUE_DELAY = 1000, ON_FAILURE = SHUTDOWN);

C. Create a server audit containing a WHERE clause

The following example creates a database, schema, and two tables for the example. The table named DataSchema.SensitiveData contains confidential data and access to the table must be recorded in the audit. The table named DataSchema.GeneralData doesn't contain confidential data. The database audit specification audits access to all objects in the DataSchema schema. The server audit is created with a WHERE clause that limits the server audit to only the SensitiveData table. The server audit presumes an audit folder exists at C:\SQLAudit.

CREATE DATABASE TestDB;
GO

USE TestDB;
GO

CREATE SCHEMA DataSchema;
GO

CREATE TABLE DataSchema.GeneralData
(
    ID INT PRIMARY KEY,
    DataField VARCHAR (50) NOT NULL
);
GO

CREATE TABLE DataSchema.SensitiveData
(
    ID INT PRIMARY KEY,
    DataField VARCHAR (50) NOT NULL
);
GO

-- Create the server audit in the master database
USE master;
GO

CREATE SERVER AUDIT AuditDataAccess TO FILE (FILEPATH = 'C:\SQLAudit\')
    WHERE object_name = 'SensitiveData';
GO

ALTER SERVER AUDIT AuditDataAccess WITH (STATE = ON);
GO

-- Create the database audit specification in the TestDB database
USE TestDB;
GO

CREATE DATABASE AUDIT SPECIFICATION [FilterForSensitiveData]
    FOR SERVER AUDIT [AuditDataAccess]
    ADD (SELECT ON SCHEMA::[DataSchema] BY [public])
    WITH(STATE = ON);
GO

-- Trigger the audit event by selecting from tables
SELECT ID,
       DataField
FROM DataSchema.GeneralData;

SELECT ID,
       DataField
FROM DataSchema.SensitiveData;
GO

-- Check the audit for the filtered content
SELECT *
FROM fn_get_audit_file('C:\SQLAudit\AuditDataAccess_*.sqlaudit', DEFAULT, DEFAULT);
GO

Transact-SQL reference

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