Two Reflected XSS Vulnerabilities in Calls to Action WordPress plugin

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

Advisory ID: HTB23274
Product: Calls to Action WordPress plugin
Vendor: InboundNow
Vulnerable Version(s): 2.4.3 and probably prior
Tested Version: 2.4.3
Advisory Publication:  October 7, 2015  [without technical details]
Vendor Notification: October 7, 2015 
Vendor Patch: October 27, 2015 
Public Disclosure: November 4, 2015 
Vulnerability Type: Cross-Site Scripting [CWE-79]
CVE Reference: CVE-2015-8350
Risk Level: Medium 
CVSSv3 Base Score: 6.1 [CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 two Cross-Site Scripting 
(XSS) vulnerabilities in a popular WordPress plugin Calls to Action. A remote 
attacker might be able to steal user's and administrator’s cookies, credentials 
and browser history, modify web page content to perform phishing attacks, or 
even to perform drive-by-download attacks by injecting malware into website 
pages when the victim follows a specially crafted link with XSS exploit.


1) Two Reflected XSS Vulnerabilities in Calls to Action WordPress plugin: 
CVE-2015-8350

1.1 Input passed via the "open-tab" HTTP GET parameter is not properly 
sanitised before being returned to the user. 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.

A simple XSS exploit below will display JavaScript popup with "ImmuniWeb" word, 
when the logged-in administrators follows the malicious link:

http://[host]/wp-admin/edit.php?post_type=wp-call-to-action&page=wp_cta_global_settings&open-tab=%27%3E%3Cscript%3Ealert%28ImmuniWeb%29%3B%3C%2Fscript%3E


1.2 Input passed via the "wp-cta-variation-id" HTTP GET parameter is not 
properly sanitised before being returned to the user. A remote attacker can 
trick a logged-in user to open a specially crafted link and execute arbitrary 
HTML and script code in browser in context of the vulnerable website.

A simple XSS exploit below will display JavaScript popup with "ImmuniWeb" word, 
when the victim follows the malicious link:

http://[host]/cta/ab-testing-call-to-action-example/?wp-cta-variation-id=%27%22%3E%3Cscript%3Ealert%28ImmuniWeb%29;%3C/script%3E

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Solution:

Update to Calls to Action 2.5.1

More Information:
https://github.com/inboundnow/cta/issues/137
https://wordpress.org/plugins/cta/changelog/

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References:

[1] High-Tech Bridge Advisory HTB23274 - 
https://www.htbridge.com/advisory/HTB23274 - Two Reflected XSS Vulnerabilities 
in Calls to Action WordPress plugin.
[2] Calls to Action WordPress plugin - http://www.inboundnow.com - Displays 
Targeted Calls to Action on your WordPress site.
[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.
[5] ImmuniWeb® SaaS - https://www.htbridge.com/immuniweb/ - hybrid of manual 
web application penetration test and cutting-edge vulnerability scanner 
available online via a Software-as-a-Service (SaaS) model.

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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.