CVE-2021-20851
📋 TL;DR
This CSRF vulnerability in the Browser and Operating System Finder WordPress plugin allows attackers to trick administrators into performing unintended actions. Attackers can hijack administrator sessions to modify plugin settings or potentially perform other administrative actions. All WordPress sites using vulnerable versions of this plugin are affected.
💻 Affected Systems
- Browser and Operating System Finder WordPress Plugin
📦 What is this software?
Browser And Operating System Finder by Browser And Operating System Finder Project
View all CVEs affecting Browser And Operating System Finder →
⚠️ Risk & Real-World Impact
Worst Case
Complete site compromise through administrator account takeover, allowing attackers to install backdoors, modify content, or escalate privileges.
Likely Case
Unauthorized plugin configuration changes, potential data manipulation, or limited administrative actions performed without consent.
If Mitigated
No impact if proper CSRF protections are implemented or plugin is updated.
🎯 Exploit Status
Exploitation requires social engineering to trick administrators into clicking malicious links while authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.2
Vendor Advisory: https://wordpress.org/plugins/browser-and-operating-system-finder/
Restart Required: No
Instructions:
1. Log into WordPress admin panel
2. Navigate to Plugins → Installed Plugins
3. Find 'Browser and Operating System Finder'
4. Click 'Update Now' if available
5. If no update button, download version 1.2+ from WordPress repository
6. Deactivate old version, upload new version, activate
🔧 Temporary Workarounds
CSRF Protection Implementation
allAdd CSRF tokens to plugin forms and validate them on submission
Plugin Deactivation
linuxTemporarily disable the vulnerable plugin until patched
wp plugin deactivate browser-and-operating-system-finder
🧯 If You Can't Patch
- Implement web application firewall with CSRF protection rules
- Restrict administrator access to trusted networks only
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Browser and Operating System Finder version numberCheck Version:
wp plugin get browser-and-operating-system-finder --field=versionVerify Fix Applied:
Confirm plugin version is 1.2 or higher in WordPress admin panel📡 Detection & Monitoring
Log Indicators:
- Unexpected plugin configuration changes
- Administrative actions from unusual IP addresses
Network Indicators:
- POST requests to plugin admin endpoints without proper referrer headers
SIEM Query:
source="wordpress" AND (plugin="browser-and-operating-system-finder" AND version<1.2)