CVE-2023-2027
📋 TL;DR
The ZM Ajax Login & Register WordPress plugin has an authentication bypass vulnerability that allows unauthenticated attackers to log in as any existing user by exploiting insufficient verification during Facebook login. This affects all WordPress sites using the plugin up to version 2.0.2. Attackers only need the target username to gain unauthorized access.
💻 Affected Systems
- ZM Ajax Login & Register WordPress Plugin
📦 What is this software?
Zm Ajax Login \& Register by Zm Ajax Login \& Register Project
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain administrative access to WordPress sites, enabling complete site takeover, data theft, malware injection, and defacement.
Likely Case
Attackers compromise user accounts, steal sensitive data, and potentially escalate to administrative privileges.
If Mitigated
Limited impact if plugin is disabled or patched, though previously compromised accounts may still pose risks.
🎯 Exploit Status
Exploitation requires only the target username and access to the vulnerable endpoint. Public proof-of-concept code is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.0.3 or later
Vendor Advisory: https://plugins.trac.wordpress.org/browser/zm-ajax-login-register/trunk/src/ALRSocial/ALRSocialFacebook.php#L58
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find 'ZM Ajax Login & Register'. 4. Click 'Update Now' if available. 5. If no update appears, manually download version 2.0.3+ from WordPress.org and replace plugin files.
🔧 Temporary Workarounds
Disable Facebook Login Feature
allTemporarily disable the vulnerable Facebook login functionality while awaiting patch.
Disable Entire Plugin
linuxDeactivate the ZM Ajax Login & Register plugin completely until patched.
wp plugin deactivate zm-ajax-login-register
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block requests to vulnerable Facebook login endpoints
- Enable two-factor authentication for all user accounts, especially administrators
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel → Plugins → Installed Plugins for ZM Ajax Login & Register version. If version is 2.0.2 or lower, system is vulnerable.Check Version:
wp plugin get zm-ajax-login-register --field=versionVerify Fix Applied:
After updating, verify plugin version shows 2.0.3 or higher in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual authentication attempts via Facebook login endpoints
- Multiple failed login attempts followed by successful login from same IP
- User account logins from unexpected locations
Network Indicators:
- HTTP POST requests to /wp-admin/admin-ajax.php with action=zm_ajax_login_register_facebook
- Traffic patterns showing authentication bypass attempts
SIEM Query:
source="wordpress.log" AND ("zm_ajax_login_register_facebook" OR "ALRSocialFacebook") AND status=200🔗 References
- https://plugins.trac.wordpress.org/browser/zm-ajax-login-register/trunk/src/ALRSocial/ALRSocialFacebook.php#L58
- https://www.wordfence.com/threat-intel/vulnerabilities/id/b10d01ec-54ef-456b-9410-ed013343a962?source=cve
- https://plugins.trac.wordpress.org/browser/zm-ajax-login-register/trunk/src/ALRSocial/ALRSocialFacebook.php#L58
- https://www.wordfence.com/threat-intel/vulnerabilities/id/b10d01ec-54ef-456b-9410-ed013343a962?source=cve
