Buffer-overflow in GO-Global for Windows 3.1.0.3270

[Luigi Auriemma <aluigi () autistici org>]

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                             Luigi Auriemma

Application:  GO-Global for Windows
              http://www.graphon.com/products/GO-GlobalforWindows.shtml
Versions:     <= 3.1.0.3270
Platforms:    Server:  Windows
              Clients: Windows, Solaris, HP-UX, IBM AIX and Linux
                       Java version not vulnerable
Bug:          buffer-overflow
Exploitation: remote, versus server and client
Date:         02 Nov 2005
Author:       Luigi Auriemma
              e-mail: aluigi () autistici org
              web:    http://aluigi.altervista.org


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


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


GO-Global for Windows is a server-based thin-client solution.
It allows users to run 32-bit Windows applications remotely from a
server, the application runs entirely on the server but is displayed on
the client.


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======
2) Bug
======


After the initial handshake where is specified the type of encryption
to use (_USERSA_), the application uses 16 bit fields for specifying
the length of the subsequent data blocks.
Both the client and the server use a small buffer which leads to a
buffer-overflow if an attacker uses a data block longer than its size.
Both server and clients are vulnerables.


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


For testing the "GO-Global for Windows" server:
  http://aluigi.altervista.org/poc/ggwbof.zip

For testing the "GO-Global for Windows" clients:
  http://aluigi.altervista.org/poc/ggwbofc.zip


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


Version 3.1.0.3281


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