CVE-2022-4939
📋 TL;DR
The WCFM Membership plugin for WordPress has a privilege escalation vulnerability that allows unauthenticated attackers to modify membership registration forms to assign administrator roles to themselves. This affects all WordPress sites using WCFM Membership plugin versions up to and including 2.10.0. Attackers can gain full administrative control of vulnerable WordPress installations.
💻 Affected Systems
- WCFM Membership WordPress Plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of WordPress site with attacker gaining administrator privileges, allowing data theft, defacement, malware installation, and further network penetration.
Likely Case
Attacker creates administrator account, takes control of website, and potentially compromises sensitive data or installs backdoors.
If Mitigated
Attack prevented by patching or workarounds, with no privilege escalation possible.
🎯 Exploit Status
Exploitation requires sending crafted AJAX requests to the vulnerable endpoint. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.10.1 and later
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find WCFM Membership plugin. 4. Click 'Update Now' if available. 5. Alternatively, download version 2.10.1+ from WordPress repository and manually update.
🔧 Temporary Workarounds
Disable vulnerable AJAX endpoint
allAdd code to functions.php to remove the vulnerable AJAX action handler
add_action('init', function() { remove_action('wp_ajax_nopriv_wcfm_ajax_controller', 'wcfm_ajax_controller'); remove_action('wp_ajax_wcfm_ajax_controller', 'wcfm_ajax_controller'); });
Disable plugin temporarily
allDeactivate WCFM Membership plugin until patched
wp plugin deactivate wc-multivendor-membership
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block requests to wp-admin/admin-ajax.php with wcfm_ajax_controller action
- Monitor user registration logs for suspicious administrator account creation
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Installed Plugins for WCFM Membership version. If version is 2.10.0 or lower, you are vulnerable.Check Version:
wp plugin get wc-multivendor-membership --field=versionVerify Fix Applied:
Verify plugin version is 2.10.1 or higher in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /wp-admin/admin-ajax.php with action=wcfm_ajax_controller
- New administrator user registrations from unexpected IP addresses
- AJAX requests with membership registration parameter modifications
Network Indicators:
- HTTP POST requests to admin-ajax.php containing 'wcfm_ajax_controller' in unauthenticated sessions
- Traffic patterns showing registration form modifications
SIEM Query:
source="web_logs" AND uri="/wp-admin/admin-ajax.php" AND method="POST" AND params.action="wcfm_ajax_controller" AND user="-"🔗 References
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2633191%40wc-multivendor-membership&new=2633191%40wc-multivendor-membership&sfp_email=&sfph_mail=
- https://www.wordfence.com/threat-intel/vulnerabilities/id/0870de2d-bca5-4d57-a07f-877a416ce0d5?source=cve
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2633191%40wc-multivendor-membership&new=2633191%40wc-multivendor-membership&sfp_email=&sfph_mail=
- https://www.wordfence.com/threat-intel/vulnerabilities/id/0870de2d-bca5-4d57-a07f-877a416ce0d5?source=cve
