CVE-2024-1895
📋 TL;DR
The Event Monster WordPress plugin is vulnerable to PHP object injection through deserialization of untrusted input from custom meta values via shortcodes. This allows authenticated attackers with contributor-level access or higher to inject malicious PHP objects. Exploitation requires a separate POP chain from another plugin or theme to achieve significant impact.
💻 Affected Systems
- Event Monster – Event Management, Tickets Booking, Upcoming Event WordPress plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
If combined with a POP chain from another plugin/theme, attackers could execute arbitrary code, delete files, or access sensitive data, potentially leading to complete system compromise.
Likely Case
Limited impact due to no built-in POP chain in the vulnerable plugin, but could enable privilege escalation or data manipulation if other vulnerable components exist.
If Mitigated
With proper access controls and no vulnerable POP chains present, impact is limited to potential plugin disruption or minor data manipulation.
🎯 Exploit Status
Exploitation requires authenticated access (contributor or higher) and depends on presence of POP chain in other installed plugins/themes.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.3.5 or later
Vendor Advisory: https://plugins.trac.wordpress.org/browser/event-monster
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find 'Event Monster' plugin. 4. Click 'Update Now' if available. 5. Alternatively, download version 1.3.5+ from WordPress repository and replace plugin files.
🔧 Temporary Workarounds
Disable Plugin
allTemporarily disable the vulnerable plugin until patched
wp plugin deactivate event-monster
Restrict User Roles
allLimit contributor and higher privileged accounts
🧯 If You Can't Patch
- Remove or restrict contributor-level user accounts
- Audit and remove any plugins/themes that might provide POP chains
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel → Plugins → Event Monster → Version number. If version is 1.3.4 or lower, system is vulnerable.Check Version:
wp plugin get event-monster --field=versionVerify Fix Applied:
Verify plugin version is 1.3.5 or higher in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to WordPress admin-ajax.php with event-monster shortcodes
- Unexpected PHP deserialization errors in web server logs
Network Indicators:
- HTTP requests containing serialized PHP objects in parameters
- Unusual shortcode usage patterns from authenticated users
SIEM Query:
source="web_logs" AND ("event-monster" OR "admin-ajax.php") AND ("unserialize" OR "O:" OR "C:")🔗 References
- https://plugins.trac.wordpress.org/browser/event-monster/tags/1.3.3/shortcode.php
- https://www.wordfence.com/threat-intel/vulnerabilities/id/41d7b3f1-a133-4678-b2d9-3f9951cbc005?source=cve
- https://plugins.trac.wordpress.org/browser/event-monster/tags/1.3.3/shortcode.php
- https://www.wordfence.com/threat-intel/vulnerabilities/id/41d7b3f1-a133-4678-b2d9-3f9951cbc005?source=cve
