Re: custom xp_cmdshell on SQL Server

[Steven M Gill <steven.gill () sungardsecurity com>]

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I have seen xp_cmdshell removed (which may be the cause of the
disabling), but it can be reloaded from the dll.  If you have the sa
password, you should be able to reload it.  You can call the
sp_addextendedproc
(http://msdn2.microsoft.com/fr-fr/library/ms164653.aspx) procedure.
In sql 7 its xpsql70.dll (it has all the extended sp - which means its
probably still on the system).  You can check which dll for what
version of sql by looking at the installed files.  if you need to know
what version of sql is running  on your target host, try executing
"select @@version".

Hope this helps!

Steve

Andy Lester wrote:
> Hello list,
>
> I am pen-testing a web app that is vulnerable to SQL Injection. The
> queries to the backend DB are done with a non-privileged user, but
> using OPENROWSET and inference-based injection I have been able to
> find the sa password and escalate privileges.
> However, xp_cmdshell seems to have been disabled, so I am trying to
> create a custom one with 'CREATE PROCEDURE'.
> The probles is that while 'CREATE PROCEDURE' works perfectly with
> "native" sa privileges (i.e.: without the OPENROWSET escalation), it
> is not working combined with the privilege escalation (i.e.: inside
> the OPENROWSET).
>
> More specifically, I am trying injecting the following query (using
> a test SQL Server 2000):
> select * from OPENROWSET('SQLOLEDB','';'sa';<password>,'declare @x
> nvarchar(1000);set @x = ''CREATE PROCEDURE customshell<snip>'';exec
> master..sp_executesql @x;select 1')
>
> The 'select 1' is added because OPENROWSET expects some data. The
> query runs correctly without errors but the custom procedure is not
> created.
>
> Any ideas on how to create such a custom procedure in a privilege
> escalation scenario ?
>
> I hope it all makes sense, and sorry for the long post.
>
> Andy
>
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