1. Application Data and Database Activities Auditing Dr. Gabriel

2. 2 Auditing Process Auditing –Negatively affects performance –Can be costly –Clearly defined objectives are necessary

3. 3 DML Action Auditing Architecture Is used for application data auditing Data Manipulation Language (DML): companies use auditing architecture for DML changes DML changes can be performed on two levels: –Row level –Column level Implemented using triggers and/or stored procedures

4. 4 DML Action Auditing Architecture (continued)

5. 5

6. 6 SQL Server Triggers A trigger is a special type of stored procedure that automatically takes effect when a language event executes 2 types –DML triggers –DDL triggers

7. 7 SQL Server Triggers DML Triggers –INSTEAD OF triggers are executed in place of the usual triggering action. can also be defined on views with one or more base tables, where they can extend the types of updates a view can support. –AFTER triggers are executed after the action of the INSERT, UPDATE, or DELETE statement is performed. can be specified only on tables. is the default when FOR is the only keyword specified

8. 8 SQL Server Triggers FunctionAFTER triggerINSTEAD OF trigger ApplicabilityTablesTables and views Quantity per table or view Multiple per triggering action (UPDATE, DELETE, and INSERT) One per triggering action (UPDATE, DELETE, and INSERT) Cascading referencesNo restrictions apply INSTEAD OF UPDATE and DELETE triggers are not allowed on tables that are targets of cascaded referential integrity constraints. Execution After: Constraint processing Declarative referential actions inserted and deleted tables creation The triggering action Before: Constraint processing In place of: The triggering action After: inserted and deleted tables creation Order of execution First and last execution may be specified Not applicable varchar(max), nvarchar(max), and varbinary(max) column references in inserted and deleted tables Allowed text, ntext, and image column references in inserted and deleted tables Not allowedAllowed

9. 9 SQL Server Triggers CREATE TRIGGER DDL statement –creates a trigger Trigger condition: –Prevents a trigger from firing –UPDATE() and COLUMNS_UPDATE() functions Logical tables: –DELETED contains original data –INSERTED contains new data

10. 10 SQL Server Triggers (continued) Restrictions—Transact-SQL statements not allowed: –ALTER and CREATE DATABASE –DISK INIT and DISK RESIZE –DROP DATABASE and LOAD DATABASE –LOAD LOG –RECONFIGURE –RESTORE DATABASE –RESTORE LOG

11. 11 Implementation of an Historical Model with SQL Server Create a history table: –Same structure as original table –Add HISTORY ID column –Possibly add Date Updated column –Possibly add User Name column –Other columns may be added Create a trigger: –inserts original row into the HISTORY table –Or inserts values of updated columns only

12. 12 Implementation of an Historical Model with SQL Server Example: Create table tPayments ( transactionid int not null primary key, customerid int not null, amount money not null, paymenttype char(2) not null check(paymenttype in ('CH','CA','WT‘,’CR’)), referencenumber varchar(100) not null default ('') ) Create table tPayments_History ( historyid uniqueidentifier primary key default(newid()), transactionid int not null, customerid int not null, amount money not null, paymenttype char(2) not null, referencenumber varchar(100) not null default (''), dateupdated datetime default(getdate()) )

13. 13 Implementation of an Historical Model with SQL Server Create trigger trgtPayments_audit on tPayments for update,delete as insert into tPayments_History (transactionid,customerid,amount, paymenttype,referencenumber) select * from deleted

14. 14 Another Implementation of a Historical Model with SQL Server alter table tpayments add username varchar(100) drop trigger trgtPayments_audit CREATE TABLE [tAuditTrail]( id uniqueidentifier NOT NULL PRIMARY KEY DEFAULT (newid()), tablename varchar(100) NOT NULL, columnname varchar(100) NOT NULL, oldamount money NOT NULL, newamount money not null, dateupdated datetime NOT NULL DEFAULT (getdate()), updatedby varchar(100) NOT NULL )

15. 15 Another Implementation of a Historical Model with SQL Server Create trigger trgtPayments_audit_upd on tPayments for update as if update(amount) begin declare @old money, @new money, @user varchar(100) select @old=amount from deleted select @new=isnull(amount,0),@user=username from inserted insert into tAuditTrail (tablename,columnname,oldamount,newamount,updatedby) values ('tpayments','amount',@old,@new,@user) end Create trigger trgtPayments_audit_del on tPayments for delete as declare @old money select @old=amount from deleted insert into tAuditTrail (tablename,columnname,oldamount,newamount,updatedby) values ('tpayments','amount',@old,’’,’’)

16. 16 Implementation of an Application Actions Model with SQL Server CREATE TABLE tApplicationAuditTrail( id uniqueidentifier NOT NULL PRIMARY KEY DEFAULT (newid()), action varchar(100) NOT NULL, actionentity varchar(100) NOT NULL, actionvalue varchar(max) NOT NULL, reason varchar(255) NOT NULL, dateupdated datetime NOT NULL DEFAULT (getdate()), updatedby varchar(100) NOT NULL, )

17. 17 Implementation of an Application Actions Model with SQL Server create proc pissuecredit @customerid int, @amount money, @reason varchar(255), @username varchar(100) as declare @transid int select @transid=max(transactionid)+1 from tpayments insert into tpayments (transactionid,customerid,amount,paymenttype,username) values(@transid,@customerid,@amount,‘CR‘, @username) insert into tApplicationAuditTrail (action,actionentity,actionvalue,reason,updatedby) values ('ISSUE CREDIT','PAYMENT',convert(varchar(max),@amount),@reason,@username)

18. 18 DDL Triggers Are used for database activities auditing Are defined for certain DB events/activities Example: CREATE TABLE ChangeLog( [LogId] [int] IDENTITY(1,1) NOT NULL, [DatabaseName] [varchar] (256) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [EventType] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [ObjectName] [varchar](256) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [ObjectType] [varchar](25) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [SqlCommand] [varchar](max) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [EventDate] [datetime] NOT NULL CONSTRAINT [DF_EventsLog_EventDate] DEFAULT (getdate()), [LoginName] [varchar](256) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL )

19. 19 DDL Triggers (Cont.) create trigger backup_objects on database for CREATE_APPLICATION_ROLE,ALTER_APPLICATION_ROLE,DROP_APPLICATION_ROLE,CREATE_ASSEMBLY, ALTER_ASSEMBLY,DROP_ASSEMBLY,ALTER_AUTHORIZATION_DATABASE,CREATE_CERTIFICATE, ALTER_CERTIFICATE,DROP_CERTIFICATE,CREATE_CONTRACT,DROP_CONTRACT, GRANT_DATABASE, DENY_DATABASE,REVOKE_DATABASE,CREATE_EVENT_NOTIFICATION,DROP_EVENT_NOTIFICATION, CREATE_FUNCTION,ALTER_FUNCTION,DROP_FUNCTION, CREATE_INDEX, ALTER_INDEX,DROP_INDEX, CREATE_MESSAGE_TYPE, ALTER_MESSAGE_TYPE, DROP_MESSAGE_TYPE,CREATE_PARTITION_FUNCTION, ALTER_PARTITION_FUNCTION,DROP_PARTITION_FUNCTION,CREATE_PARTITION_SCHEME, ALTER_PARTITION_SCHEME, DROP_PARTITION_SCHEME,CREATE_PROCEDURE,ALTER_PROCEDURE, DROP_PROCEDURE,CREATE_QUEUE,ALTER_QUEUE,DROP_QUEUE,CREATE_REMOTE_SERVICE_BINDING, ALTER_REMOTE_SERVICE_BINDING,DROP_REMOTE_SERVICE_BINDING,CREATE_ROLE, ALTER_ROLE, DROP_ROLE,CREATE_ROUTE,ALTER_ROUTE,DROP_ROUTE,CREATE_SCHEMA,ALTER_SCHEMA, DROP_SCHEMA, CREATE_SERVICE,ALTER_SERVICE,DROP_SERVICE,CREATE_STATISTICS,DROP_STATISTICS, UPDATE_STATISTICS,CREATE_SYNONYM,DROP_SYNONYM,CREATE_TABLE, ALTER_TABLE, DROP_TABLE, CREATE_TRIGGER,ALTER_TRIGGER,DROP_TRIGGER, CREATE_TYPE,DROP_TYPE, CREATE_USER,ALTER_USER, DROP_USER,CREATE_VIEW,ALTER_VIEW,DROP_VIEW, CREATE_XML_SCHEMA_COLLECTION,ALTER_XML_SCHEMA_COLLECTION,DROP_XML_SCHEMA_COLLECTION As set nocount on declare @data xml set @data = EVENTDATA() insert into changelog(databasename, eventtype, objectname, objecttype, sqlcommand, loginname) Values(@data.value('(/EVENT_INSTANCE/DatabaseName)[1]', 'varchar(256)'), @data.value('(/EVENT_INSTANCE/EventType)[1]', 'varchar(50)'), @data.value('(/EVENT_INSTANCE/ObjectName)[1]', 'varchar(256)'), @data.value('(/EVENT_INSTANCE/ObjectType)[1]', 'varchar(25)'),@data.value('(/EVENT_INSTANCE/TSQLCommand)[1]', 'varchar(max)'), @data.value('(/EVENT_INSTANCE/LoginName)[1]', 'varchar(256)'))

20. 20 Implementing SQL Profiler User interface for auditing events For each event you can audit: –Date and time of the event –User who caused the event to occur –Type of event –Success or failure of the event –Origin of the request –Name of the object accessed –Text SQL statement

21. 21 Implementing SQL Profiler (Cont) Steps for implementing SQL Profiler: –From SQL Server Management Studio click on Tools and then on SQL Profiler –In the SQL Profiler, click on File menu and select New Trace option –Connect to SQL Server –Select events based on the auditing objectives –Select columns that you wish to track –Select output options –Run the trace

22. 22 Questions ?