CVE-2024-43924: Responsive Lightbox Auth Bypass Flaw

CVE-2024-43924 Overview

A critical Missing Authorization vulnerability has been identified in the dFactory Responsive Lightbox plugin for WordPress. This broken access control flaw allows attackers to access functionality not properly constrained by Access Control Lists (ACLs), potentially enabling unauthorized actions on affected WordPress installations. The vulnerability stems from CWE-862 (Missing Authorization), indicating that the plugin fails to properly verify user permissions before allowing access to sensitive functionality.

Critical Impact

Unauthenticated attackers can bypass access controls and access restricted plugin functionality without proper authorization, potentially leading to full site compromise.

Affected Products

• dFactory Responsive Lightbox plugin for WordPress versions up to and including 2.4.7
• WordPress installations with the Responsive Lightbox & Gallery plugin installed
• All configurations of the affected plugin versions are vulnerable

Discovery Timeline

• 2024-10-23 - CVE CVE-2024-43924 published to NVD
• 2024-11-06 - Last updated in NVD database

Technical Details for CVE-2024-43924

Vulnerability Analysis

This vulnerability represents a broken access control issue in the dFactory Responsive Lightbox WordPress plugin. The flaw occurs because the plugin fails to implement proper authorization checks before allowing users to access certain functionality. Without these checks, functionality that should be restricted to authenticated administrators or specific user roles becomes accessible to unauthenticated users or users with insufficient privileges.

The vulnerability allows attackers to access functionality that is not properly constrained by ACLs, meaning the plugin does not verify whether the requesting user has the necessary permissions to perform certain actions. This is a common pattern in WordPress plugin vulnerabilities where AJAX handlers or other endpoints lack proper current_user_can() checks or nonce verification.

Root Cause

The root cause is the absence of proper authorization verification in the Responsive Lightbox plugin. When implementing WordPress plugin functionality, developers must ensure that sensitive operations verify user capabilities through WordPress's role-based access control system. In this case, the plugin exposes functionality without validating that the requesting user has appropriate permissions, violating the principle of least privilege and creating an authorization bypass condition.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker can directly access vulnerable endpoints exposed by the Responsive Lightbox plugin over HTTP/HTTPS. Since no privileges are required and the attack complexity is low, remote attackers can exploit this vulnerability to access restricted functionality that could lead to unauthorized modifications, information disclosure, or further compromise of the WordPress installation.

The vulnerability can be exploited by sending crafted requests to the affected plugin endpoints. Without proper authorization checks, the plugin processes these requests regardless of the user's authentication status or permission level. For detailed technical information about the exploitation mechanism, refer to the Patchstack Vulnerability Advisory.

Detection Methods for CVE-2024-43924

Indicators of Compromise

• Unusual HTTP requests to Responsive Lightbox plugin AJAX endpoints from unauthenticated sources
• Unexpected modifications to lightbox gallery settings or configurations
• Access logs showing requests to /wp-admin/admin-ajax.php with Responsive Lightbox-related actions from external IP addresses
• Changes to plugin settings without corresponding administrator login sessions

Detection Strategies

• Monitor WordPress access logs for suspicious requests targeting the Responsive Lightbox plugin endpoints
• Implement Web Application Firewall (WAF) rules to detect and block unauthorized access attempts to plugin AJAX handlers
• Review audit logs for plugin configuration changes that occur without authenticated administrator sessions
• Deploy endpoint detection solutions that can identify exploitation attempts against WordPress plugins

Monitoring Recommendations

• Enable comprehensive logging for WordPress AJAX requests and plugin activities
• Configure alerts for access patterns indicative of broken access control exploitation
• Regularly audit plugin versions against known vulnerability databases
• Monitor for unexpected file modifications within the Responsive Lightbox plugin directory

How to Mitigate CVE-2024-43924

Immediate Actions Required

• Update the Responsive Lightbox plugin to a version newer than 2.4.7 immediately
• If an update is not available, consider temporarily disabling the Responsive Lightbox plugin until a patch is released
• Review WordPress audit logs for signs of previous exploitation attempts
• Implement a Web Application Firewall to provide additional protection against unauthorized access attempts

Patch Information

Organizations using the dFactory Responsive Lightbox plugin for WordPress should check for available updates through the WordPress plugin repository. The vulnerability affects all versions through 2.4.7, so updating to a patched version is the primary remediation. Consult the Patchstack Vulnerability Advisory for the latest information on available patches and remediation guidance.

Workarounds

• Temporarily disable the Responsive Lightbox plugin if an immediate update is not possible
• Implement WordPress security plugins that can enforce additional access control checks
• Configure server-level access restrictions to limit who can access WordPress admin AJAX endpoints
• Use a Web Application Firewall (WAF) to filter malicious requests targeting the vulnerable plugin endpoints

# Disable the Responsive Lightbox plugin via WP-CLI until patched
wp plugin deactivate responsive-lightbox

# Alternatively, restrict access to the plugin directory at the server level
# Add to .htaccess in the plugin directory
# <Files "*.php">
#   Require all denied
# </Files>