bugtraq - Multiple vulnerabilities in Georgia SoftWorks SSH2 Server 7.01.0003

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Message-Id: <20080102205557.cff7307a.aluigi@autistici.org>
Date: Wed, 2 Jan 2008 20:55:57 +0100
From: Luigi Auriemma <aluigi@...istici.org>
To: bugtraq@...urityfocus.com, bugs@...uritytracker.com,
	news@...uriteam.com, full-disclosure@...ts.grok.org.uk,
	vuln@...unia.com, packet@...ketstormsecurity.org
Subject: Multiple vulnerabilities in Georgia SoftWorks SSH2 Server 7.01.0003


#######################################################################

                             Luigi Auriemma

Application:  Georgia SoftWorks SSH2 Server (GSW_SSHD)
              http://www.georgiasoftworks.com/prod_ssh2/ssh2_server.htm
Versions:     <= 7.01.0003
Platforms:    Windows
Bugs:         A] format string in the log function
              B] buffer-overflow in the log function
              C] buffer-overflow in the handling of the password
Exploitation: remote
Date:         02 Jan 2008
Author:       Luigi Auriemma
              e-mail: aluigi@...istici.org
              web:    aluigi.org


#######################################################################


1) Introduction
2) Bugs
3) The Code
4) Fix


#######################################################################

===============
1) Introduction
===============


GSW_SSHD is a well known commercial SSH server which acts as SSH tunnel
for the telnet server GS_Tnet.exe.


#######################################################################

=======
2) Bugs
=======

------------------------------------
A] format string in the log function
------------------------------------

The logging function used by the server is affected by a format string
vulnerability caused by the usage of vsprintf for building the first
message (like "LoginPassword(%s(%s)[%u])") and the usage of another
vsprintf for building the final log entry.
The bug can be exploitable through the username field.


--------------------------------------
B] buffer-overflow in the log function
--------------------------------------

A buffer-overflow vulnerability is located in the same logging
function.
It's enough to use an username longer than 10000 chars to exploit the
vulnerability.


--------------------------------------------------
C] buffer-overflow in the handling of the password
--------------------------------------------------

The server is affected also by another buffer-overflow this time
located in the instructions which handle the password supplied by the
client exploitable through a string longer than 800 chars.


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===========
3) The Code
===========


http://aluigi.org/poc/gswsshit.zip


#######################################################################

======
4) Fix
======


No fix


#######################################################################


--- 
Luigi Auriemma
http://aluigi.org