CVE-2024-11878 in Category Post Slider Plugin
Summary
by MITRE • 12/20/2024
The Category Post Slider plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'category-post-slider' shortcode in all versions up to, and including, 1.4 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 02/17/2025
The Category Post Slider plugin for WordPress represents a widely used component for displaying content in slider formats across numerous websites. This particular vulnerability affects all versions up to and including 1.4, creating a significant security risk for WordPress installations that utilize this plugin. The flaw exists within the plugin's 'category-post-slider' shortcode implementation, which processes user-supplied attributes without adequate sanitization measures. Security researchers have identified that the vulnerability stems from insufficient input validation and output escaping mechanisms, allowing malicious actors to inject harmful scripts into the plugin's shortcode parameters.
The technical nature of this vulnerability places it squarely within the category of stored cross-site scripting attacks, where malicious code is permanently stored on the server and executed whenever users access affected pages. Attackers with contributor-level access or higher can exploit this weakness by crafting malicious shortcode attributes that contain embedded JavaScript code. The vulnerability operates by bypassing WordPress's standard sanitization filters that should normally prevent malicious input from being processed and stored in the database. When legitimate users access pages containing the compromised shortcode, their browsers execute the injected scripts, potentially leading to session hijacking, data theft, or further exploitation of the compromised systems. This type of vulnerability is classified under CWE-79 as "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", which specifically addresses the failure to properly escape output in web applications.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers to manipulate the behavior of legitimate users' browsers and potentially gain unauthorized access to sensitive information. Contributors and above typically have sufficient privileges to modify posts and pages, making this a particularly dangerous vulnerability for multi-user WordPress environments. The stored nature of the XSS attack means that the malicious code persists indefinitely until manually removed by administrators, creating a long-term security risk. Attackers could potentially use this vulnerability to steal administrator credentials, modify content, redirect users to malicious sites, or deploy additional malware. This vulnerability directly aligns with ATT&CK technique T1566.001 for "Phishing: Spearphishing Attachment" and T1584.004 for "Compromise Software Supply Chain" when considering the potential for persistent malicious presence within WordPress installations.
Mitigation strategies for this vulnerability must include immediate plugin updates to versions that address the sanitization and escaping issues, as well as comprehensive monitoring of affected installations. WordPress administrators should implement strict input validation on all user-generated content, particularly within shortcode parameters and custom fields. Security measures should include regular security audits of installed plugins, implementing content security policies to prevent script execution, and maintaining up-to-date security patches across all WordPress components. Organizations should also consider implementing web application firewalls that can detect and block suspicious shortcode parameters, while establishing monitoring procedures to identify unauthorized modifications to content. The vulnerability underscores the critical importance of proper input sanitization and output escaping as fundamental security practices, particularly in web applications that process user-supplied data. Regular security assessments and adherence to secure coding practices, including the principles outlined in the OWASP Top Ten, are essential for preventing similar vulnerabilities from emerging in future plugin versions.