Home / vulnerabilities gswsshit.txt
Posted on 03 January 2008
Source : packetstormsecurity.org Link
#######################################################################
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@autistici.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.
#######################################################################
===========
3) The Code
===========
http://aluigi.org/poc/gswsshit.zip
#######################################################################
======
4) Fix
======
No fix
#######################################################################
---
Luigi Auriemma
http://aluigi.org