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

                             Luigi Auriemma

Application:  PopMessenger
              http://www.leadmind.com
Versions:     <= 1.60 (before 20 Sep 2004)
Platforms:    Windows
Bug:          crash
Risk:         medium
Exploitation: remote (broadcast)
Date:         21 September 2004
Author:       Luigi Auriemma
              e-mail: aluigi@altervista.org
              web:    http://aluigi.altervista.org


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


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


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

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


PopMessenger is a LAN messenger for Windows with some features.


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

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


The messages exchanged with this program are encrypted with the
Blowfish algorithm and then converted to plain-text with Base64.

The problem is located just in the Base64 function because the program
shows an alert dialog if there are illegal chars in a message (like %
or _).
After about 15 consecutive dialogs the program definitely crashs.


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

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


http://aluigi.altervista.org/poc/popmsgboom.zip


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

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


The vendor has released a new version without changing the version
number (1.60).
All the programs downloaded after the 20 September 2004 are not
vulnerable.


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


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