CVE-2021-21881
📋 TL;DR
This CVE describes an OS command injection vulnerability in Lantronix PremierWave 2050's Web Manager Wireless Network Scanner. Authenticated attackers can execute arbitrary commands on the device by sending specially-crafted HTTP requests. This affects organizations using the vulnerable firmware version.
💻 Affected Systems
- Lantronix PremierWave 2050
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attacker to execute arbitrary commands with device privileges, potentially leading to data theft, device takeover, or lateral movement within the network.
Likely Case
Attackers gaining authenticated access can execute commands to modify device configuration, install malware, or use the device as a pivot point for further attacks.
If Mitigated
With proper network segmentation and access controls, impact is limited to the isolated device with minimal data exposure.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward once credentials are obtained. Public exploit details are available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Lantronix advisory for specific patched version
Vendor Advisory: https://www.lantronix.com/support/security-advisories/
Restart Required: Yes
Instructions:
1. Check Lantronix security advisory for patched firmware version. 2. Download updated firmware from Lantronix support portal. 3. Backup device configuration. 4. Apply firmware update via Web Manager or console. 5. Verify update and restore configuration if needed.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict access to Web Manager interface to trusted IP addresses only
Configure firewall rules to allow only specific IPs to access port 80/443 on the device
Disable Wireless Scanner Feature
allDisable the vulnerable Wireless Network Scanner functionality if not required
Access Web Manager > Wireless > Scanner and disable feature if available
🧯 If You Can't Patch
- Implement strict network segmentation to isolate PremierWave devices from critical systems
- Enforce strong authentication policies and regularly rotate credentials for Web Manager access
🔍 How to Verify
Check if Vulnerable:
Check firmware version in Web Manager > System > About. If version is 8.9.0.0R4, device is vulnerable.Check Version:
Login to Web Manager and navigate to System > About page to view firmware versionVerify Fix Applied:
Verify firmware version has been updated to a version after the vulnerable release. Check Lantronix advisory for specific patched version.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to wireless scanner endpoints
- Multiple failed authentication attempts followed by successful login
- Commands executed via Web Manager that don't match normal administrative patterns
Network Indicators:
- HTTP POST requests to /goform/wirelessScanner with unusual parameters
- Outbound connections from PremierWave device to unexpected external IPs
SIEM Query:
source="premierwave" AND (url="*wirelessScanner*" AND (param="*;*" OR param="*|*" OR param="*`*"))