CVE-2021-21872
📋 TL;DR
This CVE describes an OS command injection vulnerability in Lantronix PremierWave 2050's Web Manager Diagnostics Traceroute functionality. An authenticated attacker can execute arbitrary commands on the device by sending specially-crafted HTTP requests. This affects organizations using the vulnerable Lantronix PremierWave 2050 devices.
💻 Affected Systems
- Lantronix PremierWave 2050
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to install persistent backdoors, pivot to internal networks, exfiltrate sensitive data, or disrupt industrial operations.
Likely Case
Attacker gains full control of the affected device, potentially using it as a foothold for lateral movement within the network.
If Mitigated
Limited impact due to network segmentation, strong authentication controls, and monitoring preventing successful exploitation.
🎯 Exploit Status
Exploitation requires authentication to the Web Manager interface. The vulnerability is well-documented with proof-of-concept available in the Talos Intelligence report.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.9.0.0R5 and later
Vendor Advisory: https://www.lantronix.com/support/security-advisories/
Restart Required: Yes
Instructions:
1. Download the latest firmware from Lantronix support portal. 2. Backup current configuration. 3. Upload and install the new firmware via Web Manager. 4. Reboot the device. 5. Verify the firmware version is 8.9.0.0R5 or later.
🔧 Temporary Workarounds
Disable Web Manager Access
allDisable HTTP/HTTPS access to the Web Manager interface if not required for operations.
Configuration depends on specific network setup - typically involves disabling HTTP/HTTPS services in device configuration
Network Segmentation
allIsolate PremierWave devices in separate VLANs with strict firewall rules limiting access to management interfaces.
🧯 If You Can't Patch
- Implement strict access controls to limit Web Manager access to authorized administrators only
- Deploy network monitoring and intrusion detection systems to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check the firmware version via Web Manager or CLI. If version is exactly 8.9.0.0R4, the device is vulnerable.Check Version:
Check via Web Manager interface or use SNMP queries to determine firmware versionVerify Fix Applied:
Verify firmware version is 8.9.0.0R5 or later after applying the patch.📡 Detection & Monitoring
Log Indicators:
- Unusual traceroute requests in Web Manager logs
- Multiple failed authentication attempts followed by traceroute requests
- Commands execution patterns in system logs
Network Indicators:
- HTTP POST requests to traceroute functionality with command injection patterns
- Unusual outbound connections from PremierWave devices
SIEM Query:
source="premierwave" AND (url="*/traceroute*" OR cmd="*;*" OR cmd="*|*" OR cmd="*`*" OR cmd="*$(*")