CVE-2024-13770
📋 TL;DR
This CVE describes a PHP object injection vulnerability in the Puzzles WordPress theme that allows unauthenticated attackers to inject malicious PHP objects via AJAX requests. The vulnerability only becomes dangerous if another plugin or theme with a POP chain is installed, which could enable remote code execution, file deletion, or data theft. All WordPress sites using this theme up to version 4.2.4 are affected.
💻 Affected Systems
- Puzzles | WP Magazine / Review with Store WordPress Theme
- Puzzles RTL theme for WordPress
📦 What is this software?
Puzzles by Themerex
⚠️ Risk & Real-World Impact
Worst Case
If combined with a POP chain from another plugin/theme, attackers could achieve remote code execution, delete arbitrary files, or exfiltrate sensitive data from the WordPress installation.
Likely Case
Most installations will see no immediate impact since no POP chain exists in the vulnerable theme itself, but the vulnerability creates a dangerous entry point if other vulnerable components are present.
If Mitigated
With proper security controls like WAF rules blocking suspicious AJAX requests and no POP chain components installed, the vulnerability may be unexploitable.
🎯 Exploit Status
Exploitation requires finding or creating a POP chain from other installed components. The vulnerability itself is unauthenticated and relatively easy to trigger.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: N/A
Restart Required: No
Instructions:
No official patch is available as the developer removed the theme from the repository. The only secure solution is to replace the theme entirely.
🔧 Temporary Workarounds
Disable vulnerable AJAX endpoint
WordPressRemove or disable the 'view_more_posts' AJAX action handler in the theme files to prevent exploitation
Locate and remove or comment out the add_action() call for 'wp_ajax_view_more_posts' and 'wp_ajax_nopriv_view_more_posts' in theme PHP files
Implement input validation filter
WordPressAdd a WordPress filter to sanitize or block the vulnerable parameter before processing
Add filter in functions.php: add_filter('wp_ajax_view_more_posts', 'sanitize_callback'); add_filter('wp_ajax_nopriv_view_more_posts', 'sanitize_callback');
🧯 If You Can't Patch
- Immediately replace the Puzzles theme with a secure alternative theme
- Implement strict WAF rules to block requests containing serialized PHP objects in AJAX parameters
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel > Appearance > Themes to see if Puzzles theme is active or installed. Check theme version in style.css or theme details.Check Version:
Check the theme's style.css file for Version: header, or use WordPress CLI: wp theme list --field=name,versionVerify Fix Applied:
After removing the theme, verify it no longer appears in the themes list and check that the 'view_more_posts' AJAX endpoint returns 404 or proper error.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /wp-admin/admin-ajax.php with action=view_more_posts parameter
- PHP warnings or errors related to unserialize() function in theme files
Network Indicators:
- HTTP requests to admin-ajax.php with serialized data in POST parameters
- Unusual traffic patterns to WordPress AJAX endpoints from unauthenticated users
SIEM Query:
source="wordpress.log" AND "admin-ajax.php" AND "view_more_posts" AND ("unserialize" OR "O:" OR "C:")