Format string and buffer-overflow in Lst Network Print Server 9.4.2 build 105

[Luigi Auriemma <aluigi () autistici org>]

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                             Luigi Auriemma

Application:  Larson Software Technology Network Print Server
              http://www.cgmlarson.com/products/NetworkPrintServer.php
Versions:     <= 9.4.2 build 105
Platforms:    Windows
Bugs:         A] format string in logging
              B] license buffer-overflow
Exploitation: remote
Date:         11 Feb 2008
Author:       Luigi Auriemma
              e-mail: aluigi () autistici org
              web:    aluigi.org


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


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


LstNPS is a CGM print server for Windows.


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2) Bugs
=======

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A] format string in logging
---------------------------

The server is affected by a format string vulnerability located in the
logging functions (by default enabled and set on "Information") which
passes the log message directly to vsnprintf without the format
argument.


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B] license buffer-overflow
--------------------------

The LICENSE command handled by the server leads to a buffer-overflow
vulnerability when a license string longer than 128 bytes is copied in
a stack buffer using strncpy in the wrong way.


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


A]
echo USEP %n%n%n%s%s%s|nc SERVER 3114 -v -v

B]
echo LICENSE aaaaa...160...aaaaa|nc SERVER 3114 -v -v


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4) Fix
======


No Fix


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