CVE-2021-34417
📋 TL;DR
This vulnerability allows remote command injection through the network proxy configuration page in Zoom's on-premise components. An authenticated web portal administrator can exploit improper input validation to execute arbitrary commands on affected systems. This affects Zoom On-Premise Meeting Connector, Recording Connector, Virtual Room Connector, and related load balancer components.
💻 Affected Systems
- Zoom On-Premise Meeting Connector Controller
- 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?
Zoom On Premise Meeting Connector Controller by Zoom
View all CVEs affecting Zoom On Premise Meeting Connector Controller →
Zoom On Premise Meeting Connector Mmr by Zoom
View all CVEs affecting Zoom On Premise Meeting Connector Mmr →
Zoom On Premise Recording Connector by Zoom
View all CVEs affecting Zoom On Premise Recording Connector →
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attacker to execute arbitrary commands with system privileges, potentially leading to data exfiltration, lateral movement, or complete system takeover.
Likely Case
Authenticated administrator could execute commands to modify system configurations, install malware, or create backdoors for persistent access.
If Mitigated
With proper access controls and network segmentation, impact limited to isolated administrative interface with no critical system access.
🎯 Exploit Status
Exploitation requires authenticated administrative access to the web portal. The vulnerability is in input validation for proxy password field.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Meeting Connector: 4.6.365.20210703+, Recording Connector: 3.8.45.20210703+, Virtual Room Connector: 4.4.6868.20210703+, Load Balancer: 2.5.5496.20210703+
Vendor Advisory: https://explore.zoom.us/en/trust/security/security-bulletin
Restart Required: Yes
Instructions:
1. Download latest patched version from Zoom portal. 2. Backup current configuration. 3. Stop Zoom services. 4. Install updated version. 5. Restart services. 6. Verify functionality.
🔧 Temporary Workarounds
Restrict Administrative Access
allLimit access to Zoom web portal administration interface to only trusted administrators using network controls.
Disable Proxy Configuration
allIf proxy configuration is not required, disable or restrict access to the network proxy settings page.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Zoom on-premise components from critical systems
- Enforce multi-factor authentication for all administrative accounts accessing the Zoom web portal
🔍 How to Verify
Check if Vulnerable:
Check current version in Zoom web portal admin interface under System Information or via SSH to the server and check installed package version.Check Version:
For Linux systems: dpkg -l | grep zoom or rpm -qa | grep zoomVerify Fix Applied:
Verify version numbers match or exceed patched versions listed in vendor advisory. Test proxy configuration page functionality.📡 Detection & Monitoring
Log Indicators:
- Unusual commands in system logs following web portal access
- Multiple failed authentication attempts to admin interface
- Changes to proxy configuration outside normal maintenance windows
Network Indicators:
- Unusual outbound connections from Zoom servers
- Traffic to unexpected destinations following admin portal access
SIEM Query:
source="zoom-logs" AND (event="proxy_config_change" OR event="admin_login") AND (command_execution OR suspicious_pattern)