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Hillstone Software HS TFTP Server Denial Of Service Vulnerability

SecPod Technologies (www.secpod.com)
Author: Prabhu S Angadi
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SecPod ID: 1031					21/09/2011 Issue Discovered
						04/10/2011 Vendor Notified
						No Response from Vendor
						02/12/2011 Advisory Released


Class: Denial Of Service                Severity: Medium


Overview:
---------
Hillstone Software HS TFTP Server version 1.3.2 is prone to a denial of
service vulnerability.


Technical Description:
----------------------
The vulnerability is caused due to improper validation of WRITE/READ Request
Parameter containing long file name, which allows remote attackers to crash
the service.


Impact:
--------
Successful exploitation could allow an attacker to cause denial of service
condition.


Affected Software:
------------------
Hillstone Software HS TFTP 1.3.2


Tested on:
-----------
Hillstone Software HS TFTP 1.3.2 on Windows XP SP3 & Win 7.
Older versions might be affected.


References:
-----------
http://secpod.org/blog/?p=419
http://www.hillstone-software.com/index.htm
http://www.hillstone-software.com/hs_tftp_details.htm
http://secpod.org/advisories/SecPod_Hillstone_Software_HS_TFTP_Server_DoS.txt
http://secpod.org/exploits/SecPod_Exploit_Hillstone_Software_HS_TFTP_Server_DoS.py


Proof of Concept:
----------------
http://secpod.org/exploits/SecPod_Exploit_Hillstone_Software_HS_TFTP_Server_DoS.py


Solution:
----------
Not available


Risk Factor:
-------------
    CVSS Score Report:
        ACCESS_VECTOR          = NETWORK
        ACCESS_COMPLEXITY      = LOW
        AUTHENTICATION         = NOT_REQUIRED
        CONFIDENTIALITY_IMPACT = NONE
        INTEGRITY_IMPACT       = NONE
        AVAILABILITY_IMPACT    = PARTIAL
        EXPLOITABILITY         = PROOF_OF_CONCEPT
        REMEDIATION_LEVEL      = UNAVAILABLE
        REPORT_CONFIDENCE      = CONFIRMED
        CVSS Base Score        = 5 (AV:N/AC:L/Au:N/C:N/I:N/A:P)
        Risk factor            = Medium