CVE-2024-9428
📋 TL;DR
The Popup Builder WordPress plugin before version 4.3.5 contains a stored cross-site scripting (XSS) vulnerability in its settings. This allows authenticated administrators to inject malicious scripts that execute when other users view affected pages, even in WordPress multisite installations where unfiltered_html capability is restricted. Only WordPress sites using vulnerable versions of this specific plugin are affected.
💻 Affected Systems
- Popup Builder WordPress Plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An attacker with admin privileges could inject malicious JavaScript that steals session cookies, redirects users to phishing sites, or performs actions on behalf of authenticated users, potentially leading to complete site compromise.
Likely Case
Malicious admin injects tracking scripts or defaces the website by modifying content displayed to users through the popup functionality.
If Mitigated
With proper user access controls and regular admin account monitoring, impact is limited to potential defacement or minor data collection from users viewing affected popups.
🎯 Exploit Status
Exploitation requires admin-level access to WordPress. The vulnerability is in plugin settings that should only be accessible to administrators.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.3.5
Vendor Advisory: https://wpscan.com/vulnerability/6e246547-e509-48db-88ae-b2f943398377/
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find 'Popup Builder' plugin. 4. Click 'Update Now' if update is available. 5. Alternatively, download version 4.3.5+ from WordPress repository and manually update.
🔧 Temporary Workarounds
Remove vulnerable plugin
allTemporarily disable or remove the Popup Builder plugin until patched version can be installed
wp plugin deactivate popup-builder
wp plugin delete popup-builder
Restrict admin access
allImplement strict access controls and monitoring for WordPress administrator accounts
🧯 If You Can't Patch
- Implement Content Security Policy (CSP) headers to restrict script execution
- Enable WordPress security plugins that provide XSS protection and admin activity monitoring
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel → Plugins → Installed Plugins → Popup Builder version. If version is below 4.3.5, you are vulnerable.Check Version:
wp plugin get popup-builder --field=versionVerify Fix Applied:
After updating, verify Popup Builder plugin shows version 4.3.5 or higher in WordPress plugins list.📡 Detection & Monitoring
Log Indicators:
- Unusual modifications to popup builder settings
- Admin users making unexpected changes to plugin configurations
Network Indicators:
- Script tags with unusual sources in popup content responses
SIEM Query:
source="wordpress" AND (event="plugin_updated" AND plugin="popup-builder" AND version<"4.3.5") OR (event="plugin_settings_modified" AND plugin="popup-builder")