Document Title:
===============
CNNVD Gov CN #1 - Filter Bypass & Persistent Vulnerability


References (Source):
====================
http://www.vulnerability-lab.com/get_content.php?id=1209


Release Date:
=============
2014-02-21


Vulnerability Laboratory ID (VL-ID):
====================================
1209


Common Vulnerability Scoring System:
====================================
5.5


Product & Service Introduction:
===============================
CNNVD (China National Vulnerability Database of Information Security) is the most famous chinese vulnerability database of the east.
The website and web-application is self-coded content management system and the program is connected to the chinese gov cyber security agency.

Copy of the Vendor Homepage: http://www.cnnvd.org.cn/vulnerability )


Abstract Advisory Information:
==============================
The Vulnerability Laboratory Research Team discovered a filter bypass and persistent input validation web vulnerability in the official China National Vulnerability Database of Information Security.


Vulnerability Disclosure Timeline:
==================================
2014-02-19: Researcher Notification & Coordination (Benjamin Kunz Mejri)
2014-02-20: Vendor Notification (CNNVD Security Team)
2014-02-20: Vendor Response/Feedback (CNNVD Security Team)
2014-02-21: Vendor Fix/Patch (CNNVD Developer Team)
2014-02-21: Public Disclosure (Vulnerability Laboratory)


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


Affected Product(s):
====================
China Information Security Evaluation Center
Product: China National Vulnerability Database of Information Security (Gov) 2014 Q1


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


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


Technical Details & Description:
================================
A filter bypass and persistent web vulnerability has been discovered in the official China National Vulnerability Database of Information Security.
The filter bypass allows remote attackers to bypass the regular web filter validation of the cms by usage of prepared malicious and encoded script codes.
The persistent input validation web vulnerability allows remote attackers to inject own malicious persistent script codes on the application-side of the 
vulnerable module.

The vulnerability is located in the edit formular POST method request. The vulnerable parameter value are `cont_details` and `displayitem`. Remote 
attackers and privileged user accounts are able to inject own malicious script codes on the application-side. The attack vector is persistent and the 
injection request method is POST. The validation of the web formular does not encode base64 strings in html object tags which results in the persistent 
execution after the include to the item list via moderation. Attackers can encode the advisory in a special crafted plain format to provoke a public 
execution after the inject. The security risk of the filter bypass and persistent input validation web vulnerability is estimated as high(+) with a cvss 
(common vulnerability scoring system) count of 5.5(+)|(-)5.6.

Exploitation of the filter bypass and persistent input validation web vulnerability requires no privileged application user account but a privileged 
moderator web-application user account with low user interaction (verifiy/activate issue). Successful exploitation of the vulnerability results in 
filter validation bypass and session hijacking, persistent phishing, persistent external redirect and persistent manipulation of affected or 
connected module context.

Vulnerable Module(s):
          [+] ../vulnerability/show

Vulnerable Parameter(s):
          [+] cont_details > displayitem

Affected Module(s):
          [+] ../show/cv_id/


Proof of Concept (PoC):
=======================
The filter bypass issue and persistent input validation web vulnerability can be exploited by remote attackers without privileged application user account 
but a privileged moderator web-application user account with low user interaction (verifiy/activate issue). For security demonstration or to reproduce the 
vulnerability follow the provided information and steps below to continue.

PoC: ../cv_id/2014020225

       <tr>
          <td colspan="2" valign="top"><h3><img src="/Public/images/cnnvd3_12_24.jpg" alt="" height="33" width="693"></h3>
          <div class="cont_details">
                         <p class="displayitem">SeaMonkey和Thunderbird都是由美国Mozilla基金会开发。SeaMonkey是一套免费、开源以及跨平台的网络套装软件。
Thunderbird是从Mozilla Application Suite中独立出来的一套电子邮件客户端软件，支持IMAP、POP邮件协议以及HTML邮件格式。
<br>        Mozilla Thunderbird 17.x至17.0.8版本，Thunderbird ESR 17.x至17.0.10版本，SeaMonkey 
2.19及之前的版本中存在跨站脚本漏洞。远程攻击者可通过创建包含data: URL的<[PERISSTNET INJECTED SCRIPT CODE!]>元素的电子邮件消息利用该漏洞注入任意Web脚本或HTML。</p>
            </div></td>
        </tr>


Reference(s):
http://www.cnnvd.org.cn/vulnerability/show/cv_id/2014020225

Note: The vulnerability was part of the vulnerability exchange partners program between the cnnvd and vulnerability-labs.


Solution - Fix & Patch:
=======================
The vulnerability can be patched by a secure encode and parse of the vulnerable cont_details > displayitem class values.
Restrict the description input fields and disallow script codes like frames, alerts and other script code tags.
Encode also the description output website of the ../show/cv_id/ to prevent execution of already included and wrong encoded advisories in the cnnvd database.


Security Risk:
==============
The security risk of the filter bypass issue and the persistent input validation web vulnerability is estimated as medium(+).


Credits & Authors:
==================
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (bkm@evolution-sec.com) [www.vulnerability-lab.com]


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