CVE-2021-33532
📋 TL;DR
This vulnerability allows authenticated low-privilege users to execute arbitrary commands on Weidmueller Industrial WLAN devices through command injection in the iw_webs functionality. Attackers can gain remote control over affected devices by sending specially crafted diagnostic script file names. Industrial organizations using these WLAN devices are affected.
💻 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
Complete device takeover allowing attackers to disrupt industrial operations, modify device configurations, install persistent backdoors, or pivot to other network segments.
Likely Case
Unauthorized command execution leading to device configuration changes, data exfiltration, or disruption of industrial WLAN connectivity.
If Mitigated
Limited impact if proper network segmentation and access controls prevent low-privileged users from accessing vulnerable interfaces.
🎯 Exploit Status
Exploitation requires authentication but is straightforward once authenticated. The vulnerability is in a diagnostic script file name parameter that gets passed to iw_system without proper sanitization.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references - check vendor advisory for specific patched versions
Vendor Advisory: https://cert.vde.com/en-us/advisories/vde-2021-026
Restart Required: Yes
Instructions:
1. Check the VDE advisory for specific affected versions. 2. Contact Weidmueller support for firmware updates. 3. Apply the latest firmware patch. 4. Restart affected devices. 5. Verify the patch is applied successfully.
🔧 Temporary Workarounds
Restrict Access to Management Interfaces
allLimit network access to device management interfaces to only authorized administrative systems
Use firewall rules to restrict access to device management ports
Implement network segmentation for industrial devices
Remove Unnecessary User Accounts
allRemove or disable low-privilege user accounts that are not required for operations
Check device user management interface
Remove unnecessary accounts
🧯 If You Can't Patch
- Implement strict network segmentation to isolate industrial WLAN devices from general network traffic
- Monitor and log all access to device management interfaces and alert on suspicious command execution patterns
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against vendor advisory. If running affected versions and iw_webs functionality is enabled, device is vulnerable.Check Version:
Check device web interface or CLI for firmware version information (vendor-specific command)Verify Fix Applied:
Verify firmware version has been updated to patched version specified in vendor advisory and test that command injection is no longer possible.📡 Detection & Monitoring
Log Indicators:
- Unusual diagnostic script file names in device logs
- Unexpected iw_system command executions
- Multiple failed authentication attempts followed by successful login and command execution
Network Indicators:
- Unusual traffic patterns to/from industrial WLAN devices
- Unexpected outbound connections from industrial devices
- Traffic to device management interfaces from unauthorized sources
SIEM Query:
source="industrial_wlan_device" AND (event="iw_system" OR event="diagnostic_script") AND command="*;*" OR command="*|*" OR command="*`*"