UK Cookie Consent - Persistent Cross-Site Scripting

# Exploit Title: UK Cookie Consent v2.3.9 - Persistent Cross-Site Scripting
# Date: 2018-04-22
# Exploit Author: B0UG
# Vendor Homepage: https://catapultthemes.com/
# Software Link: https://en-gb.wordpress.org/plugins/uk-cookie-consent/#description
# Version: Tested on version 2.3.9 (older versions may also be affected)
# Tested on: WordPress
# Category : Webapps
# CVE: CVE-2018-10310

I. VULNERABILITY
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Persistent Cross-Site Scripting
 
II. BACKGROUND
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UK Cookie Consent is a WordPress plugin which has been designed to display cookie consent notifications on a WordPress website.

III. DESCRIPTION
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A persistent cross-site scripting vulnerability has been identified in the web interface of the plugin that allows the execution of arbitrary HTML/script code to be executed in a victim's web browser.

IV. PROOF OF CONCEPT
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1) Access WordPress control panel.
2) Navigate to the 'Pages'.
3) Add a new page and insert the script you wish to inject into the page title.
4) Now navigate to 'Settings' and select 'Cookie Consent'.
5) Now click on the 'Content' tab.
6) Your injected script will now be executed.

V. IMPACT
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An attacker can execute malicious code in a victim user's browser to perform various activities such as stealing cookies, session tokens, credentials and personal data amongst others.
 
VI. SYSTEMS AFFECTED
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WordPress websites running "UK Cookie Consent" plugin version 2.3.9  (older versions may also be affected).
 
VII. REMEDIATION
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Update to the latest version available. Implement a web application such as Wordfence.

VIII. DISCLOSURE TIMELINE
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April 22, 2018 1: Vulnerability identified.
April 22, 2018 2: Informed developer of the vulnerability.
April 23, 2018 3: Developer acknowledged the vulnerability.
April 23, 2018 4: Developer issued a security patch.

Special thanks goes to the team at Catapult Themes for their fast response, great understanding and patching the issue.