CVE-2021-34411
📋 TL;DR
This vulnerability allows local privilege escalation during Zoom Rooms for Windows installation. If the installer runs with elevated privileges (like via SCCM), attackers can launch Internet Explorer with those same elevated privileges. This affects Windows systems running Zoom Rooms for Conference Room before version 5.3.0.
💻 Affected Systems
- Zoom Rooms for Conference Room for Windows
📦 What is this software?
Rooms by Zoom
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise where an attacker gains SYSTEM-level privileges on the Windows machine, enabling complete control over the system.
Likely Case
Local attacker gains administrative privileges on the compromised Windows system, allowing installation of malware, data theft, or persistence mechanisms.
If Mitigated
Limited impact if installations are performed by standard users without elevated privileges and proper endpoint security controls are in place.
🎯 Exploit Status
Exploitation requires local access to the system and knowledge of the vulnerability during installation process.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.3.0 and later
Vendor Advisory: https://explore.zoom.us/en/trust/security/security-bulletin/
Restart Required: Yes
Instructions:
1. Download Zoom Rooms for Windows version 5.3.0 or later from official Zoom website. 2. Uninstall previous version. 3. Install the updated version. 4. Restart the system.
🔧 Temporary Workarounds
Install without elevated privileges
windowsInstall Zoom Rooms using standard user privileges instead of administrator/SCCM deployment
Restrict Internet Explorer execution
windowsUse AppLocker or similar to block Internet Explorer execution during installation processes
🧯 If You Can't Patch
- Ensure Zoom Rooms installations are performed only by standard users without elevated privileges
- Implement endpoint detection and response (EDR) to monitor for privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check Zoom Rooms version in application settings or via 'wmic product get name,version' commandCheck Version:
wmic product where "name like '%Zoom Rooms%'" get name,versionVerify Fix Applied:
Confirm Zoom Rooms version is 5.3.0 or higher in application settings📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs showing Internet Explorer launched during Zoom installation
- Process creation events for iexplore.exe with elevated privileges
Network Indicators:
- Unusual network activity from Internet Explorer process with elevated privileges
SIEM Query:
process_name="iexplore.exe" AND parent_process_name="ZoomInstaller.exe" AND integrity_level="System"