CVE-2021-4457
📋 TL;DR
The ZoomSounds WordPress plugin before version 6.05 contains an unrestricted file upload vulnerability. Unauthenticated attackers can upload arbitrary files to the web server, potentially leading to remote code execution. This affects all WordPress sites running vulnerable versions of the ZoomSounds plugin.
💻 Affected Systems
- ZoomSounds WordPress Plugin
📦 What is this software?
Zoomsounds by Digitalzoomstudio
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete server compromise, data theft, ransomware deployment, or website defacement.
Likely Case
Webshell upload allowing persistent backdoor access, file manipulation, or privilege escalation.
If Mitigated
File upload attempts blocked or logged, with no successful exploitation.
🎯 Exploit Status
Simple HTTP POST request to vulnerable endpoint with file upload payload.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.05 and later
Vendor Advisory: https://wpscan.com/vulnerability/07259a61-8ba9-4dd0-8d52-cc1df389c0ad
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find ZoomSounds plugin. 4. Click 'Update Now' if available. 5. If no update available, deactivate and delete plugin.
🔧 Temporary Workarounds
Block vulnerable endpoint via .htaccess
allPrevent access to the vulnerable PHP file using web server rules.
# Add to .htaccess in WordPress root directory
<Files "zoomSounds-master/zoomSounds-master/zoom-admin/upload.php">
Order Allow,Deny
Deny from all
</Files>
Web Application Firewall rule
allBlock requests to the vulnerable upload endpoint.
# Example WAF rule to block requests to upload.php
# Block: /wp-content/plugins/zoomSounds-master/zoomSounds-master/zoom-admin/upload.php
🧯 If You Can't Patch
- Immediately deactivate and remove the ZoomSounds plugin from all WordPress installations.
- Implement strict file upload validation and monitoring on web servers.
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel → Plugins → Installed Plugins for ZoomSounds version. If version is below 6.05, system is vulnerable.Check Version:
# Check via WordPress CLI
wp plugin list --name=zoomsounds --field=version
# Or check file directly
cat /path/to/wp-content/plugins/zoomSounds-master/zoomSounds-master/zoom-admin/upload.php | grep -i versionVerify Fix Applied:
Confirm ZoomSounds plugin version is 6.05 or higher, or verify plugin is completely removed.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /wp-content/plugins/zoomSounds-master/zoomSounds-master/zoom-admin/upload.php
- File uploads to unexpected locations
- Webshell creation in upload directories
Network Indicators:
- Unusual outbound connections from web server
- POST requests to upload.php from external IPs
SIEM Query:
source="web_server_logs" AND (uri="/wp-content/plugins/zoomSounds-master/zoomSounds-master/zoom-admin/upload.php" OR file_upload="*.php")