CVE-2024-8739 in ReCaptcha Integration Plugin
Summary
by MITRE • 11/02/2024
The ReCaptcha Integration for WordPress 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, 1.2.5. 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 • 03/01/2025
The vulnerability identified as CVE-2024-8739 affects the ReCaptcha Integration for WordPress plugin, which is a widely used security tool designed to protect WordPress websites from automated spam and bot attacks through Google's reCAPTCHA service. This particular flaw exists in versions up to and including 1.2.5, representing a significant security risk for WordPress sites that rely on this plugin for their protection mechanisms. The vulnerability stems from improper handling of URL parameters within the plugin's codebase, creating an avenue for malicious actors to exploit the system through reflected cross-site scripting attacks.
The technical implementation of this vulnerability occurs when the plugin utilizes the WordPress add_query_arg function without proper HTML escaping of the resulting URL parameters. This function is designed to add query arguments to URLs but fails to sanitize the output when incorporating user-controllable data into the URL structure. When an attacker crafts a malicious URL containing specially formatted script tags within query parameters, these scripts can be reflected back to users who visit the compromised page. The vulnerability specifically targets the plugin's handling of URL construction where user input is directly incorporated into the URL without appropriate sanitization or escaping mechanisms. This flaw aligns with CWE-79, which defines Cross-Site Scripting (XSS) vulnerabilities that occur when untrusted data is sent to a web browser without proper validation or escaping.
The operational impact of this vulnerability is substantial as it allows unauthenticated attackers to inject arbitrary web scripts into pages that execute when users interact with maliciously crafted links. This means that even without any authentication credentials, an attacker can potentially compromise users' browsers by tricking them into clicking on seemingly legitimate links that contain malicious payloads. The reflected nature of this XSS vulnerability means that the malicious script is not stored on the server but is instead reflected back to the user through the server's response, making it particularly difficult to detect and prevent. Attackers can leverage this vulnerability to perform various malicious activities including session hijacking, credential theft, defacement of web pages, or redirection to malicious sites that can further compromise user systems.
The security implications extend beyond simple script injection as this vulnerability can be exploited to create more sophisticated attack vectors that leverage the trust relationship between users and the WordPress site. When users click on malicious links, the injected scripts can access cookies, session information, or other sensitive data that the user has previously accessed on the site. This vulnerability represents a critical weakness in the plugin's security architecture and demonstrates the importance of proper input validation and output escaping in web applications. The attack surface is particularly concerning because WordPress sites often contain sensitive user data, administrative interfaces, and business-critical information that could be compromised through successful exploitation of this XSS vulnerability.
Organizations using the affected plugin version should immediately implement mitigations including updating to the latest available version where the vulnerability has been patched, implementing proper input validation and output escaping measures, and monitoring for suspicious user activity or unauthorized access attempts. Additionally, administrators should consider implementing Content Security Policy (CSP) headers to provide an additional layer of protection against script injection attacks. The vulnerability highlights the critical need for regular security audits of WordPress plugins and the importance of maintaining current versions to protect against known security issues. This case exemplifies the ATT&CK technique of "Cross-Site Scripting" and represents a common attack pattern that security professionals should be vigilant against when implementing web application security measures.