SSH Explorer v1.97 - Denial of Service Vulnerability

Document Title:
===============
SSH Explorer v1.97 - Denial of Service Vulnerability


References (Source):
====================
http://www.vulnerability-lab.com/get_content.php?id=326
CNNVD-201112-149


Release Date:
=============
2011-11-19


Vulnerability Laboratory ID (VL-ID):
====================================
326


Product & Service Introduction:
===============================
Der SSH Explorer ist ein SSH/Telnet Client und Terminal Emulationssoftware, die es ermöglicht die Administration 
von Linux Servern einfacher zu gestalten. Mit dem File View Panel können Sie durch die Remote Verzeichnisse und 
Dateien navigieren als wären diese direkt auf Ihrem Computer gespeichert. Der SSH Explorer hat ebenso einen Satz 
von nützlichen Linux Kommandos integriert, der Ihnen erlaubt komplizierte Befehle zu Skripten, somit müssen Sie 
diese nicht immer wieder neu tippen. Unterstützt werden eine VT100 Terminal Emulation, SSH1, SSH2 und das 
Telnet Protokoll.

(Copy of the Vendor Homepage: http://www.pcfreunde.de/download/d11544/ssh-explorer/)


Abstract Advisory Information:
==============================
Vulnerability Lab Team discovered a local Denial of Service vulnerability in SSH Explorer v1.97.


Vulnerability Disclosure Timeline:
==================================
2011-11-20:	Public or Non-Public Disclosure


Discovery Status:
=================
Published


Exploitation Technique:
=======================
Local


Severity Level:
===============
Medium


Technical Details & Description:
================================
A Denial of Service vulnerability is detected in SSH Explorer v1.97. Local attackers can crash the software 
process via denial of service vulnerability. The bug is located on the groups-name module when processing the 
content of the snippet list description.


Vulnerable Section(s): 
		                                	[+] Snippet List - Description


--- Error/Exception Logs ---

  Problemereignisname:			AppHangB1
  Anwendungsname:			SSHExplorer.exe
  Anwendungsversion:			0.0.0.0
  Anwendungszeitstempel:		2a425e19
  Absturzsignatur:			17d3
  Absturztyp:				0
  Betriebsystemversion:			6.1.7601.2.1.0.768.3
  Gebietsschema-ID:			1031
  Zusätzliche Absturzsignatur 1:	17d3b5d57715568670c128b2e71cc052
  Zusätzliche Absturzsignatur 2:	571d
  Zusätzliche Absturzsignatur 3:	571db8b6553550ce54cc5b50842649bd
  Zusätzliche Absturzsignatur 4:	17d3
  Zusätzliche Absturzsignatur 5:	17d3b5d57715568670c128b2e71cc052
  Zusätzliche Absturzsignatur 6:	571d
  Zusätzliche Absturzsignatur 7:	571db8b6553550ce54cc5b50842649bd



Picture(s):
							../1.png
							../2.png


Proof of Concept (PoC):
=======================
The denial of service vulnerability can be exploited by local attackers or local low privileged user accounts. 
For demonstration or reproduce ...


Manually reproduce ...

1. Start the software
2. open the code snippet module and choose a groupname on the list
3. Include a large string & save the input
4. Close the module and open the same section again
5. Result: Service freeze and stable process crash via apphang


Report(s):
							../AppHang_SSHExplorer.exe_3aae5c5145af76d2e5e3b212656360bfecdba5_0d66dfa8
							../AppHang_SSHExplorer.exe_3aae5c5145af76d2e5e3b212656360bfecdba5_178055c1
							../AppHang_SSHExplorer.exe_7b9ea29e4aab730f258a954f20a06ccd888efa_1e8d9f00
							../AppHang_SSHExplorer.exe_df68e426db7b919656d5ec108bb27dce1813dd82_15d0d240
							../crash-report


Solution - Fix & Patch:
=======================
Restrict the input with a specific maximum after the save when processing to request the saved same input form.


Security Risk:
==============
The security risk of the stable local denial of service vulnerability are estimated as medium(-).


Credits & Authors:
==================
Vulnerability Research Laboratory  -  N/A  Anonymous


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=========================
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