CVE-2014-6604 in Subscribe2 Plugin
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in class-s2-list-table.php in the Subscribe2 plugin before 10.16 for WordPress allows remote attackers to inject arbitrary web script or HTML via the ip parameter.
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Analysis
by VulDB Data Team • 02/06/2021
The CVE-2014-6604 vulnerability represents a critical cross-site scripting flaw within the Subscribe2 WordPress plugin, specifically affecting versions prior to 10.16. This vulnerability resides in the class-s2-list-table.php file and exploits a failure to properly sanitize user input, creating an avenue for remote attackers to execute malicious web scripts or HTML code within the context of affected websites. The vulnerability manifests when the ip parameter is manipulated during the plugin's administrative operations, particularly within list table displays where subscriber information is managed. This flaw directly impacts the security posture of WordPress installations relying on the Subscribe2 plugin for email subscription management, as it allows attackers to inject malicious payloads that can persist and execute against unsuspecting users who access the affected administrative interfaces.
The technical exploitation of this vulnerability follows the classic XSS attack pattern where unvalidated input flows into the web application's output generation without proper sanitization or encoding. The ip parameter serves as the injection vector, allowing attackers to craft malicious payloads that get rendered in the administrative interface without appropriate security controls. This vulnerability is categorized under CWE-79 as a failure to sanitize or incorrectly sanitize input data, specifically manifesting as a reflected cross-site scripting vulnerability. The flaw demonstrates a critical weakness in the plugin's input validation mechanisms, where the application fails to implement proper output encoding or sanitization when displaying user-supplied data within HTML contexts. Attackers can leverage this vulnerability to execute scripts in the context of the victim's browser, potentially leading to session hijacking, credential theft, or redirection to malicious sites.
The operational impact of CVE-2014-6604 extends beyond simple script injection, as it provides attackers with a foothold for more sophisticated attacks within the WordPress administrative environment. When exploited, this vulnerability enables unauthorized individuals to manipulate the plugin's administrative interface, potentially gaining access to subscriber lists, modifying subscription settings, or injecting persistent malicious code that could affect multiple users. The vulnerability's remote nature means attackers do not require local access or credentials to exploit it, making it particularly dangerous for WordPress sites that maintain public administrative interfaces or have exposed plugin management functions. This weakness can be leveraged in combination with other vulnerabilities to escalate privileges within the WordPress environment, as the attacker can manipulate the administrative interface to perform actions that would normally require legitimate administrative credentials. The impact is amplified when considering that many WordPress installations lack proper security monitoring or input validation in their plugin ecosystems, making such vulnerabilities particularly attractive targets for automated exploitation tools.
Organizations should prioritize immediate patching of the Subscribe2 plugin to version 10.16 or later, which implements proper input sanitization and output encoding for the ip parameter. Security measures should include implementing Content Security Policy headers to limit script execution contexts, deploying web application firewalls to detect and block malicious input patterns, and conducting regular security audits of installed plugins to identify similar vulnerabilities. The remediation process must also include monitoring for any exploitation attempts through log analysis and implementing proper input validation controls at multiple layers of the application architecture. Additionally, administrators should consider implementing network segmentation and access controls to limit the potential impact of successful exploitation, while ensuring that all plugin updates are verified through official channels to prevent the installation of malicious code disguised as security patches. This vulnerability highlights the importance of maintaining up-to-date security practices and proper input validation as outlined in the OWASP Top Ten and ATT&CK framework's defensive techniques for preventing code injection vulnerabilities.