CVE-2021-33528
📋 TL;DR
This vulnerability allows authenticated low-privilege users on Weidmueller Industrial WLAN devices to escape restricted console menus and gain root system access through specially crafted menu selection strings. It affects multiple versions of Weidmueller's industrial wireless networking equipment used in operational technology environments.
💻 Affected Systems
- Weidmueller Industrial WLAN devices
📦 What is this software?
Ie Wl Vl Ap Br Cl Eu Firmware by Weidmueller
Ie Wl Vl Ap Br Cl Eu Firmware by Weidmueller
Ie Wl Vl Ap Br Cl Us Firmware by Weidmueller
Ie Wl Vl Ap Br Cl Us Firmware by Weidmueller
Ie Wlt Vl Ap Br Cl Eu Firmware by Weidmueller
Ie Wlt Vl Ap Br Cl Eu Firmware by Weidmueller
Ie Wlt Vl Ap Br Cl Us Firmware by Weidmueller
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain full root access to industrial WLAN devices, allowing them to disrupt network operations, intercept sensitive industrial communications, or pivot to other critical systems.
Likely Case
Malicious insiders or compromised low-privilege accounts escalate to root privileges, enabling unauthorized configuration changes, data exfiltration, or persistence mechanisms.
If Mitigated
With proper access controls and network segmentation, impact is limited to isolated industrial network segments without affecting core operations.
🎯 Exploit Status
Requires authenticated access but exploitation appears straightforward once authenticated
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references
Vendor Advisory: https://cert.vde.com/en-us/advisories/vde-2021-026
Restart Required: Yes
Instructions:
1. Contact Weidmueller support for firmware updates. 2. Download latest firmware from vendor portal. 3. Backup device configuration. 4. Apply firmware update via web interface or console. 5. Verify update and restore configuration if needed.
🔧 Temporary Workarounds
Restrict Console Access
allDisable or restrict access to iw_console functionality for low-privilege users
# Review and modify user permissions in device configuration
# Remove console access from non-admin accounts
Network Segmentation
allIsolate industrial WLAN devices from general network access
# Configure firewall rules to restrict access to management interfaces
# Implement VLAN segmentation for OT networks
🧯 If You Can't Patch
- Implement strict access controls allowing only trusted administrators to access device management interfaces
- Monitor for unusual privilege escalation attempts and console access patterns
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against vendor advisory; test if low-privilege users can access restricted console menusCheck Version:
# Check firmware version via web interface or CLI command specific to Weidmueller devicesVerify Fix Applied:
Verify firmware version is updated per vendor recommendations; test that low-privilege users cannot escape restricted console📡 Detection & Monitoring
Log Indicators:
- Unusual console access by low-privilege users
- Multiple failed menu selection attempts
- Root privilege escalation events
Network Indicators:
- Unexpected management interface access from non-admin IPs
- Unusual traffic patterns from industrial WLAN devices
SIEM Query:
source="weidmueller_wlan" AND (event_type="console_access" OR user_privilege_change="escalation")