CVE-2021-20782
📋 TL;DR
This CSRF vulnerability in Software License Manager WordPress plugin allows attackers to trick administrators into performing unintended actions by sending malicious requests while logged in. It affects all WordPress sites running Software License Manager plugin versions before 4.4.6. Attackers could modify plugin settings or perform administrative functions without proper authorization.
💻 Affected Systems
- Software License Manager WordPress Plugin
📦 What is this software?
Software License Manager by Tipsandtricks Hq
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the WordPress site through administrative account takeover, allowing attackers to install backdoors, modify content, steal data, or pivot to other systems.
Likely Case
Unauthorized changes to license management settings, creation of fraudulent licenses, or disruption of legitimate license validation processes.
If Mitigated
Limited impact with proper CSRF protections and administrative awareness, potentially causing minor configuration changes that can be reverted.
🎯 Exploit Status
CSRF attacks are well-understood and easy to implement. Exploitation requires social engineering to trick administrators into clicking malicious links.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.4.6
Vendor Advisory: https://wordpress.org/plugins/software-license-manager/
Restart Required: No
Instructions:
1. Log into WordPress admin panel
2. Navigate to Plugins → Installed Plugins
3. Find Software License Manager
4. Click 'Update Now' if available
5. If manual update needed, download version 4.4.6+ from WordPress.org
6. Deactivate old plugin, upload new version, activate
🔧 Temporary Workarounds
CSRF Protection Headers
allImplement Content Security Policy and anti-CSRF tokens at web server level
# Apache: Add to .htaccess
Header set X-Frame-Options "DENY"
Header set Content-Security-Policy "frame-ancestors 'none'"
# Nginx: Add to config
add_header X-Frame-Options "DENY";
add_header Content-Security-Policy "frame-ancestors 'none'";
Plugin Deactivation
linuxTemporarily disable the vulnerable plugin until patched
wp plugin deactivate software-license-manager
🧯 If You Can't Patch
- Restrict administrative access to trusted networks only using firewall rules
- Implement mandatory two-factor authentication for all WordPress administrator accounts
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Software License Manager → Version. If version is below 4.4.6, system is vulnerable.Check Version:
wp plugin get software-license-manager --field=versionVerify Fix Applied:
Verify plugin version shows 4.4.6 or higher in WordPress admin panel. Test administrative functions to ensure CSRF tokens are present in forms.📡 Detection & Monitoring
Log Indicators:
- Multiple administrative actions from same session in rapid succession
- Unexpected plugin configuration changes
- License creation/modification events without corresponding user intent
Network Indicators:
- POST requests to /wp-admin/admin-ajax.php or plugin endpoints without Referer headers
- Cross-origin requests to administrative endpoints
SIEM Query:
source="wordpress.log" AND ("software-license-manager" OR "slm_") AND (action="update" OR action="save" OR action="create") | stats count by src_ip, user🔗 References
- https://jvn.jp/en/jp/JVN89054582/index.html
- https://wordpress.org/plugins/software-license-manager/
- https://www.tipsandtricks-hq.com/software-license-manager-plugin-for-wordpress
- https://jvn.jp/en/jp/JVN89054582/index.html
- https://wordpress.org/plugins/software-license-manager/
- https://www.tipsandtricks-hq.com/software-license-manager-plugin-for-wordpress
