CVE-2014-4855 in Polylang
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Polylang plugin before 1.5.2 for WordPress allows remote attackers to inject arbitrary web script or HTML via vectors related to a user description. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 03/18/2019
The CVE-2014-4855 vulnerability represents a critical cross-site scripting flaw within the Polylang plugin for WordPress, affecting versions prior to 1.5.2. This vulnerability resides in the plugin's handling of user descriptions, creating a pathway for remote attackers to execute malicious scripts within the context of other users' browsers. The Polylang plugin serves as a multilingual solution for WordPress, enabling website administrators to manage content in multiple languages while maintaining a single WordPress installation. The vulnerability specifically targets the plugin's user management functionality where user descriptions are processed and displayed without adequate input sanitization or output encoding mechanisms.
The technical exploitation of this XSS vulnerability occurs when an attacker crafts malicious script code within a user description field and subsequently injects it into the plugin's administrative interface or public-facing user profile pages. The flaw stems from insufficient validation and sanitization of user-supplied input, allowing attackers to bypass WordPress's built-in security measures that typically protect against such injection attacks. This vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security where user input is not properly escaped before being rendered in web pages. The attack vector specifically involves the manipulation of user description fields that are later displayed in contexts where HTML content is rendered without proper encoding, creating an environment where malicious scripts can execute with the privileges of the victim user.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, defacement of user profiles, and potential privilege escalation within the WordPress administration panel. When an administrator or authenticated user views a compromised user profile page, the injected scripts execute in their browser context, potentially allowing attackers to steal cookies, modify user permissions, or redirect users to malicious websites. This vulnerability is particularly concerning in multi-user environments where administrators may regularly review user descriptions or profile information, as it creates a persistent attack surface that can be exploited repeatedly. The vulnerability also aligns with ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment, where attackers can use compromised user descriptions as a delivery mechanism for more sophisticated attacks.
Mitigation strategies for CVE-2014-4855 primarily focus on immediate patching of the Polylang plugin to version 1.5.2 or later, which includes proper input sanitization and output encoding mechanisms. Administrators should implement comprehensive input validation for all user-supplied content, particularly in profile fields and description areas, ensuring that all potentially dangerous characters are properly escaped or filtered. The implementation of Content Security Policy (CSP) headers can provide additional defense-in-depth measures by restricting the sources from which scripts can be executed on user profile pages. Regular security audits of WordPress plugins should include verification of input handling practices and output encoding mechanisms, with particular attention to plugins that manage user profiles or display user-generated content. Additionally, administrators should consider implementing role-based access controls that limit the ability of users to modify profile information that could potentially contain malicious content, while also maintaining regular backups to quickly restore systems in case of successful exploitation.