CVE-2021-34416
📋 TL;DR
This vulnerability allows authenticated administrators of Zoom's on-premise web portal to execute arbitrary commands on the underlying system by sending malicious input when updating network configuration settings. It affects organizations running vulnerable versions of Zoom's on-premise Meeting Connector, Recording Connector, Virtual Room Connector, and Load Balancer. Attackers could gain full control of affected systems.
💻 Affected Systems
- Zoom on-premise Meeting Connector
- Zoom on-premise Meeting Connector MMR
- Zoom on-premise Recording Connector
- Zoom on-premise Virtual Room Connector
- Zoom on-premise Virtual Room Connector Load Balancer
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the on-premise Zoom infrastructure, allowing attackers to execute arbitrary commands, install malware, pivot to internal networks, and potentially access sensitive meeting data.
Likely Case
Privileged attackers or compromised admin accounts could execute commands to disrupt services, steal data, or maintain persistence in the environment.
If Mitigated
With proper access controls and network segmentation, impact would be limited to the specific Zoom on-premise component, preventing lateral movement.
🎯 Exploit Status
Exploitation requires administrative credentials to the web portal. The vulnerability is in input validation when updating network configuration.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.6.360.20210325 for Meeting Connector and MMR, 3.8.44.20210326 for Recording Connector, 4.4.6752.20210326 for Virtual Room Connector, 2.5.5495.20210326 for Load Balancer
Vendor Advisory: https://explore.zoom.us/en/trust/security/security-bulletin/
Restart Required: Yes
Instructions:
1. Download the latest patched version from Zoom's support portal. 2. Backup current configuration. 3. Apply the update following Zoom's upgrade documentation. 4. Restart the service/application. 5. Verify the update was successful.
🔧 Temporary Workarounds
Restrict Administrative Access
allLimit access to the administrative web portal to only necessary personnel using network segmentation and strict access controls.
Network Segmentation
allIsolate Zoom on-premise components from critical internal networks to limit potential lateral movement.
🧯 If You Can't Patch
- Implement strict access controls and multi-factor authentication for administrative accounts
- Monitor and audit all administrative access to the Zoom web portal
🔍 How to Verify
Check if Vulnerable:
Check the version of your Zoom on-premise components via the administrative web interface or system logs.Check Version:
Check via Zoom administrative web portal under System Information or About sectionsVerify Fix Applied:
Verify the version number matches or exceeds the patched versions listed in the fix section.📡 Detection & Monitoring
Log Indicators:
- Unusual administrative login patterns
- Unexpected network configuration changes
- Suspicious command execution in system logs
Network Indicators:
- Unexpected outbound connections from Zoom appliances
- Unusual administrative traffic patterns
SIEM Query:
search 'Zoom' AND ('admin login' OR 'configuration change' OR 'command execution')