RE: SQL injection from within a table - is it possible?

["Burnett, Robert" <burnettr () Fortrex com>]

Peter,

Building on what Kevin stated, there is a flaw in the scenario you presented in your post.  Suppose your username was 
"bob", and it was stored in a table called "table", in a field called "name".

The query:

select name from table

will NOT become

select bob from table

It will just be: select name from table.  "bob" will be the value returned.

Now, if you were querying for a specific username, you could do: select name from table where name = 'bob', but that 
requires you to know beforehand that you are looking for "bob".

Going back to your initial question about a "stored" SQL Injection exploit, I suppose that if an application was 
pulling a value from the database by doing a SELECT query and then blindly injecting that retrieved value into a 
subsequent query, then an exploit could be performed if that stored value was some maliciously crafted SQL code.

For example, if you somehow got the value ' OR 'a'='a into the name field, and then the application retrieved that 
value, stored it in the variable $username, and then executed the query "SELECT * from table2 WHERE 
username='$username';", the resulting query is:

SELECT * from table2 WHERE username='' OR 'a'='a'; 

And we get all the records in the table returned to us.

You get the idea. 

Thanks. 

Robert Burnett
Fortrex Technologies
5303 Spectrum Drive 
Frederick, MD 21703
Toll Free: 1-877-367-8739
Fax: 301-947-3539
E-Mail: burnettr () fortrex com



-----Original Message-----
From: Peter Bair [mailto:peterbair100 () hotmail com]
Sent: Thursday, January 06, 2005 8:00 PM
To: pen-test () securityfocus com
Subject: SQL injection from within a table - is it possible?


Is it possible to store an SQL injection string into a MSSQL database table, so when the database performs an action 
like through a stored proc, the SQL injection attack takes place?

Not through the normal means of SQL injection via a web base means, but if you have the means of storing the data into 
the table directly.

Example:
An application has a users name in a table.  Is it possible to assign the users name as the SQL injection string, 
something like
   name from table; exec master.xp_cmdshell "ping me"; --

so when the database is running a stored procedure with a  select clause like

   select name from table

it really is becomes

select name from table; exec master.xp_cmdshell "ping me" ;-- from table


Of course using the SQL query analyzer on the database table, all this works ok.

But when I insert the SQL injection string into the table, as the name, and then query the table nothing happens.

Is it possible or have I missed the point here?

Thanks Peter.
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