CVE-2023-0540 in GS Filterable Portfolio Plugin
Summary
by MITRE • 02/21/2023
The GS Filterable Portfolio WordPress plugin before 1.6.1 does not validate and escape some of its shortcode attributes before outputting them back in a page/post where the shortcode is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks.
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Analysis
by VulDB Data Team • 03/23/2023
The vulnerability identified as CVE-2023-0540 affects the GS Filterable Portfolio WordPress plugin version 1.6.0 and earlier, representing a critical security flaw that enables stored cross-site scripting attacks through improper input validation and output escaping mechanisms. This vulnerability specifically targets the plugin's shortcode functionality, which is commonly used to display portfolio items and filterable content within WordPress environments. The security issue arises from the plugin's failure to properly sanitize and escape shortcode attributes before rendering them back to users within the web page context.
The technical flaw manifests in the plugin's handling of user-supplied data within its shortcode implementation. When administrators or users with contributor privileges and above embed the plugin's shortcode within posts or pages, the system fails to validate and escape certain attributes before outputting them to the browser. This oversight creates a persistent XSS vector where malicious scripts can be stored within the WordPress database and subsequently executed whenever affected pages are loaded by other users. The vulnerability is particularly concerning because it requires minimal privilege escalation, as contributors can exploit this weakness to compromise the entire WordPress installation.
From an operational impact perspective, this vulnerability exposes WordPress sites using the affected plugin to significant security risks including unauthorized data theft, session hijacking, and potential full system compromise. The stored nature of the XSS attack means that once malicious code is injected, it persists until manually removed from the database, making it particularly dangerous for high-traffic websites where multiple users may be affected. Attackers can leverage this vulnerability to steal administrator credentials, inject malicious content, redirect users to phishing sites, or perform other malicious activities that compromise the integrity of the entire WordPress installation.
The vulnerability aligns with CWE-79 which describes Cross-Site Scripting flaws, specifically focusing on the failure to escape output data in web applications. This weakness directly maps to ATT&CK technique T1566.001 which covers the use of malicious content in web applications to execute code on target systems. The attack surface is further expanded by the fact that WordPress plugins often have broad access to site functionality and user data, making compromised plugins particularly dangerous. Security practitioners should note that this vulnerability affects not just individual users but entire WordPress ecosystems that rely on the affected plugin for portfolio management and content display.
The recommended mitigation strategy involves immediate upgrading to GS Filterable Portfolio plugin version 1.6.1 or later, which contains the necessary patches to address the input validation and output escaping deficiencies. Additionally, administrators should implement proper input sanitization practices and regularly audit plugin installations for known vulnerabilities. Network monitoring solutions should be configured to detect potential exploitation attempts, and security headers including Content Security Policy should be implemented to provide additional protection layers. Regular security assessments of WordPress installations, including plugin and theme vulnerability scanning, remain essential for maintaining robust security postures against similar threats.