CVE-2015-5714 in WordPress
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in WordPress before 4.3.1 allows remote attackers to inject arbitrary web script or HTML by leveraging the mishandling of unclosed HTML elements during processing of shortcode tags.
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Analysis
by VulDB Data Team • 08/21/2022
The vulnerability identified as CVE-2015-5714 represents a critical cross-site scripting flaw in WordPress versions prior to 4.3.1, specifically targeting the improper handling of HTML elements within shortcode processing mechanisms. This weakness enables remote attackers to execute malicious scripts in the context of a victim's browser session, potentially compromising user data and system integrity. The vulnerability stems from WordPress's insufficient sanitization of HTML content when processing shortcode tags that contain unclosed HTML elements, creating an attack surface where malicious input can be injected and executed without proper validation.
The technical exploitation of this vulnerability occurs through the manipulation of shortcode parameters that contain improperly closed HTML tags, allowing attackers to inject malicious JavaScript code or HTML content into WordPress posts, pages, or comments. When WordPress processes these shortcodes, it fails to adequately sanitize the input, particularly when encountering unclosed HTML elements such as <img>, <br>, or <hr> tags that are not properly terminated. This processing flaw creates a persistent XSS vector where attacker-controlled content can be rendered as legitimate HTML, executing in the browser context of any user who views the affected content. The vulnerability specifically aligns with CWE-79, which describes improper neutralization of input during web page generation, and falls under the broader category of injection flaws that compromise web application security.
The operational impact of CVE-2015-5714 extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, data exfiltration, and redirection to malicious sites. Attackers can leverage this vulnerability to target logged-in administrators or regular users, potentially gaining elevated privileges or accessing sensitive information. The vulnerability affects WordPress installations that process user-generated content through shortcodes, making it particularly dangerous in environments where users can submit posts, comments, or other content that gets processed by the shortcode engine. This weakness can be exploited in various contexts including blog comments, contact forms, custom post types, and any area where shortcode functionality is enabled, creating widespread potential for exploitation across different WordPress implementations.
Mitigation strategies for CVE-2015-5714 primarily focus on immediate patching of WordPress installations to version 4.3.1 or later, which includes proper sanitization of HTML elements during shortcode processing. Organizations should implement comprehensive input validation and output escaping mechanisms, ensuring that all user-generated content is properly sanitized before being processed or displayed. Security measures should include configuring WordPress to limit shortcode usage in user-contributed content, implementing Content Security Policy headers to restrict script execution, and conducting regular security audits of shortcode implementations. Additionally, administrators should monitor for suspicious content patterns and maintain updated security tools to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper HTML sanitization in web applications and aligns with ATT&CK technique T1566, which covers social engineering through malicious content injection, highlighting the need for robust content validation mechanisms in content management systems.