Title:
======
LAN Messenger v1.2.28 - Persistent Software Vulnerability


Date:
=====
2012-05-16


References:
===========
http://www.vulnerability-lab.com/get_content.php?id=


VL-ID:
=====
541


Common Vulnerability Scoring System:
====================================
7.5


Introduction:
=============
LAN Messenger is a free and open source cross-platform instant messaging application for communication over a 
local network. It does not require a server. A number of useful features including event notifications, file transfer 
and message logging are provided.

(Copy of the Website: http://lanmsngr.sourceforge.net )


Abstract:
=========
The Vulnerability Laboratory Research Team discovered a persistent remote vulnerability in LAN Messenger v1.2.28.


Report-Timeline:
================
2012-05-16:  Public or Non-Public Disclosure


Status:
========
Published


Exploitation-Technique:
=======================
Remote


Severity:
=========
High


Details:
========
A persistent software vulnerability is detected in in LAN Messenger v1.2.28. The bug is located in the profile display 
& nickname validation of the software. The vulnerability allows an attacker (remote) to implement own malicious script codes as 
profile. The code is getting executed when the attacker writes the victim a message. The vulnerable nickname input is getting 
executed as output of the messagebox when processing to write a message. Successful exploitation can lead in persistent hijacking, 
external malicious redirects, persistent script code execution to compromise the connected network client system.

Vulnerable Module(s):
        [+] Username as seen by Contacts - Messagebox Display & Input

Picture(s):
        ../1.png


Proof of Concept:
=================
The persistent profile vulnerability can be exploited by remote attackers with low required inter action. 
For demonstration or reproduce ...


1. Open LAN Messenger v1.2.28 click on the top menu > Tools 
2. Switch to > Preferences > Account
3. Include to the Username as seen by Contacts your own persistent script code with char obfuscation trick
4. write the target system your message to exploit persistent via profile display nickname


PoC:
"><iFrAmE sRc=A oNlOaD=aLeRt("VL") <
... or
%22%3E%3C%69%46%72%41%6D%45%20%73%52%63%3D%41%20%6F%4E%6C%4F%61%44%3D%61%4C%65%52%74%28%22%56%4C%22%29%20%3C


Risk:
=====
The security risk of the persistent remote web vulnerability is estimated as high.


Credits:
========
Vulnerability Research Laboratory - Benjamin Kunz Mejri  (bkm@vulerability-lab.com)


Disclaimer:
===========
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                 Copyright © 2012 | Vulnerability Laboratory



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