SQL Server data change and Security

in our environ any user who login with sa they can change any table data.

so i write trigger to capture changed data like who change, from which IP etc this

CREATE TRIGGER [TRG_Users]
ON [dbo].[UserRights] AFTER INSERT, UPDATE, DELETE
AS

DECLARE @strIP VARCHAR(MAX)

SET @strIP=(SELECT dbo.GetCurrentIP())

IF EXISTS (SELECT * FROM INSERTED) AND EXISTS (SELECT * FROM DELETED)
    --PRINT 'Update happened';
    INSERT INTO Logger(IPAddress,Status)
    VALUES (@strIP,'UPDATE')
ELSE
IF EXISTS (SELECT * FROM INSERTED)
    --PRINT 'Insert happened';
    INSERT INTO Logger(IPAddress,Status)
    VALUES (@strIP,'INSERT')
ELSE
    --PRINT 'Delete happened';
    INSERT INTO Logger(IPAddress,Status)
    VALUES (@strIP,'DELETE')


CREATE FUNCTION [dbo].[GetCurrentIP] ()  
RETURNS varchar(255)  
AS  
BEGIN  
   DECLARE @IP_Address varchar(255);  

   SELECT @IP_Address = client_net_address  
   FROM sys.dm_exec_connections  
   WHERE Session_id = @@SPID;  

  Return @IP_Address;  
  END

but the problem is user can change data after disabling the trigger on specific table. so trigger will not fire and user can seamlessly change data.

so guide me what is the best way to capture data change and log them. so no one can bypass the security. please do not tell me disable sa account because i am looking for different approach to capture the change data. is there any secure way exist in sql server 2005/2008 if yes then please discuss here. thanks

Solution

Problem with SA is that all security checks are skipped for this login (or any other login in sysadmin role for that matter). So, you can't revoke any privilege from SA and also there's nothing you can do on instance level that SA cannot bypass.

Like others already said, don't let anyone login as a sysadmin unless there's real sysadmin work to be done. Best practice is to disable SA login altogether.

On a cnstructive side, your best bet otherwise is to create a SQL Server Audit session and use Windows security log as a target. This way you'll at least know who and when stopped the audit.