CVE-2024-9231 in Membership Plugin
Summary
by MITRE • 10/22/2024
The WP-Members Membership Plugin plugin for WordPress is vulnerable to Reflected Cross-Site Scripting due to the use of add_query_arg without appropriate escaping on the URL in all versions up to, and including, 3.4.9.5. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 03/03/2025
The WP-Members Membership Plugin for WordPress represents a widely used membership management solution that enables website administrators to control access to content and manage user registrations. This plugin has been identified with a critical reflected cross-site scripting vulnerability that affects all versions up to and including 3.4.9.5. The vulnerability stems from improper handling of URL parameters within the plugin's codebase, specifically when utilizing the add_query_arg function without adequate escaping mechanisms. This flaw creates a security gap that allows malicious actors to inject malicious scripts into web pages that will execute when users navigate to affected URLs.
The technical implementation of this vulnerability occurs when the plugin processes user-supplied input through URL parameters without proper sanitization or escaping before incorporating them into the page output. The add_query_arg function, which is designed to add or modify query arguments in URLs, fails to apply appropriate escaping when these arguments are subsequently rendered in HTML contexts. This creates a classic reflected XSS vector where an attacker can craft a malicious URL containing script code that gets executed in the victim's browser when the page is loaded. The vulnerability is particularly dangerous because it requires no authentication from the attacker, making it accessible to anyone who can craft malicious links.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the capability to perform various malicious activities through the victim's browser context. An attacker could potentially steal session cookies, redirect users to malicious sites, deface the website, or perform actions on behalf of authenticated users if they can manipulate the session state. The reflected nature of this vulnerability means that the malicious payload is not stored on the server but is instead reflected back to the user through the application's response, making it easier to deliver attacks through phishing emails, social engineering, or compromised websites. This vulnerability directly maps to CWE-79 which identifies improper neutralization of input during web page generation, and aligns with ATT&CK technique T1566.001 for spearphishing via email.
Mitigation strategies for this vulnerability should prioritize immediate patching to the latest available version of the WP-Members plugin where the XSS flaw has been addressed. Administrators should implement comprehensive input validation and output escaping mechanisms for all user-supplied data, particularly when constructing URLs or rendering parameters in HTML contexts. Additional protective measures include implementing Content Security Policy headers to limit script execution, monitoring for suspicious URL patterns, and educating users about the dangers of clicking untrusted links. The vulnerability also underscores the importance of regular security audits and keeping all WordPress plugins updated to address known security issues. Organizations should consider implementing web application firewalls to detect and block malicious payloads, and establish incident response procedures to quickly address any exploitation attempts that may occur.