CVE-2021-24419 in WP YouTube Lyte Plugin
Summary
by MITRE • 07/13/2021
The WP YouTube Lyte WordPress plugin before 1.7.16 did not sanitise or escape its lyte_yt_api_key and lyte_notification settings before outputting them back in the page, allowing high privilege users to set XSS payload on them and leading to stored Cross-Site Scripting issues.
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Analysis
by VulDB Data Team • 07/15/2021
The WP YouTube Lyte WordPress plugin vulnerability CVE-2021-24419 represents a critical stored cross-site scripting flaw that emerged in versions prior to 1.7.16. This vulnerability specifically targets the plugin's handling of user-controllable input parameters within the WordPress admin interface, creating a persistent security risk for websites utilizing this popular YouTube embedding plugin. The flaw resides in the plugin's failure to properly sanitize and escape sensitive configuration settings before rendering them back to users within the web page context, thereby enabling malicious actors with appropriate privileges to inject malicious scripts that persist across user sessions.
The technical implementation of this vulnerability stems from improper input validation and output escaping mechanisms within the plugin's settings handling code. Attackers with high privilege user accounts can manipulate the lyte_yt_api_key and lyte_notification parameters through the WordPress admin interface, injecting malicious JavaScript payloads that are subsequently stored in the plugin's configuration. When other users access the affected WordPress admin pages or frontend interfaces where these settings are displayed, the stored scripts execute in their browsers, creating a vector for various malicious activities including session hijacking, credential theft, and unauthorized administrative actions. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and represents a classic case of stored XSS where malicious content is permanently saved and executed during subsequent page loads.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with persistent access to compromised WordPress installations. High privilege users who can modify plugin settings include administrators, editors, and other roles with sufficient permissions to access the lyte_yt_api_key and lyte_notification configuration fields. Once exploited, the stored XSS attacks can lead to complete compromise of the WordPress site, allowing attackers to modify content, steal administrator credentials, inject malicious advertisements, or redirect users to phishing sites. The vulnerability's persistence means that even after the initial injection, the malicious scripts continue to execute whenever affected pages are loaded, creating a long-term security threat that can remain undetected for extended periods. This aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as the vulnerability enables attackers to execute JavaScript code within the context of legitimate user sessions.
Mitigation strategies for CVE-2021-24419 involve immediate plugin version updates to 1.7.16 or later, which contain proper input sanitization and output escaping mechanisms. Administrators should also implement additional security measures including regular security audits of installed plugins, monitoring of user accounts with elevated privileges, and implementation of web application firewalls that can detect and block suspicious script injections. The vulnerability highlights the importance of proper input validation and output escaping practices, as outlined in OWASP Top Ten categories and security best practices for WordPress plugin development. Organizations should conduct thorough vulnerability assessments to ensure all WordPress installations are updated and monitor for similar issues in other plugins that may not properly sanitize user input before rendering it in web pages, as this represents a common pattern in web application security flaws that can have significant operational consequences for website security and user trust.