Solved

Prevent SQL Injection

Posted on 2009-05-19
5
610 Views
Last Modified: 2012-05-07
Hi to all,

I have the code below and I want to make sure that it is the best way to try and prevent SQL injection.

I am using Free text for my search in order to let the user type in a description of the item. I am also using full text search on that table.

What would I need to do more to prevent successful attacks on my DB?
Any suggestion would be welcomed.

Thanks
Public Shared Function LoadItemSearch(ByVal ItemDescription As String) As SqlDataReader

            Dim connection As New SqlConnection _

            (RMSConnectionString.StoreCon.ConnectionString)
 

            Dim SQLCommand As SqlClient.SqlCommand

            Dim strSQL As String

            connection.Open()

            Try
 

                strSQL = "Select  Item.ID, Item.ItemLookupCode, UPPER(Item.Description) As Description,    " & _

                            "Item.ExtendedDescription AS ItemDescription, Item.PictureName  " & _

                            " FROM Item INNER JOIN Department ON Item.DepartmentID = Department.ID    " & _

                            " WHERE (Item.Inactive = 0) And Item.WebItem = 0 And Item.ItemType <> 7 And Item.Quantity > 0   " & _

                            " And FreeText(Description, @Item) " & _

                            " ORDER BY SubDescription2 DESC"
 

                SQLCommand = New SqlClient.SqlCommand(strSQL, connection)

                SQLCommand.Parameters.Add(New SqlParameter("@Item", Data.SqlDbType.VarChar)).Value _

                = ItemDescription

               

                Dim MyReader As SqlDataReader = SQLCommand.ExecuteReader

                Return MyReader

                connection.Close()

                SQLCommand.Dispose()

                connection.Dispose()

            Catch Exp As SqlClient.SqlException

                Throw Exp

            End Try

        End Function

Open in new window

0
Comment
Question by:ALawrence007
5 Comments
 
LVL 15

Assisted Solution

by:mohan_sekar
mohan_sekar earned 125 total points
Comment Utility
0
 
LVL 2

Accepted Solution

by:
d1rtyw0rm earned 200 total points
Comment Utility
You are doing great by using parameterised queries.

This is where the SQL Command uses a parameter instead of injecting the values directly into the command. The particular second-order attack above would not have been possible if parameterised queries had been used.

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

Stored Procedures add an extra layer of abstraction in to the design of a software system. This means that, so long as the interface on the stored procedure stays the same, the underlying table structure can change with no noticeable consequence to the application that is using the database. This layer of abstraction also helps put up an extra barrier to potential attackers. If access to the data in SQL Server is only ever permitted via stored procedures, then permission does not need to be explicitly set on any of the tables. Therefore, none of the tables should ever need to be exposed directly to outside applications. For an outside application to read or modify the database, it must go through stored procedures. Even though some stored procedures, if used incorrectly, could potentially damage the database, anything that can reduce the attack surface is beneficial.

Stored procedures can be written to validate any input that is sent to them to ensure the integrity of the data beyond the simple constraints otherwise available on the tables. Parameters can be checked for valid ranges. Information can be cross checked with data in other tables.

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

Encrypt sensitive data.
Access the database using an account with the least privileges necessary.
Install the database using an account with the least privileges necessary.
Ensure that data is valid.
Do a code review to check for the possibility of second-order attacks.
Use parameterised queries.
Use stored procedures.
Re-validate data in stored procedures.
Ensure that error messages give nothing away about the internal architecture of the application or the database.


http://unixwiz.net/techtips/sql-injection.html

0
 
LVL 21

Assisted Solution

by:Tapan Pattanaik
Tapan Pattanaik earned 125 total points
Comment Utility
0
 
LVL 48

Assisted Solution

by:jpaulino
jpaulino earned 50 total points
Comment Utility
You have allot of links provided already, but basically you need to use Stored Procedures with parameters passed to him, to ensure that you're SQL Injection safe.
0
 

Author Closing Comment

by:ALawrence007
Comment Utility
Thank you SO much guys!
I added Stored procs to make my site more secure
0

Featured Post

6 Surprising Benefits of Threat Intelligence

All sorts of threat intelligence is available on the web. Intelligence you can learn from, and use to anticipate and prepare for future attacks.

Join & Write a Comment

Suggested Solutions

Having an SQL database can be a big investment for a small company. Hardware, setup and of course, the price of software all add up to a big bill that some companies may not be able to absorb.  Luckily, there is a free version SQL Express, but does …
Ever needed a SQL 2008 Database replicated/mirrored/log shipped on another server but you can't take the downtime inflicted by initial snapshot or disconnect while T-logs are restored or mirror applied? You can use SQL Server Initialize from Backup…
Using examples as well as descriptions, and references to Books Online, show the documentation available for date manipulation functions and by using a select few of these functions, show how date based data can be manipulated with these functions.
Via a live example, show how to extract information from SQL Server on Database, Connection and Server properties

763 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

9 Experts available now in Live!

Get 1:1 Help Now