CVE-2023-46685
📋 TL;DR
A hard-coded password vulnerability in the telnetd functionality of LevelOne WBR-6013 routers allows attackers to execute arbitrary commands with root privileges. This affects LevelOne WBR-6013 routers running specific vulnerable firmware versions. Attackers can gain complete control of affected devices.
💻 Affected Systems
- LevelOne WBR-6013
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to network infiltration, data exfiltration, botnet recruitment, and persistent backdoor installation.
Likely Case
Router takeover enabling traffic interception, DNS manipulation, credential theft, and lateral movement within the network.
If Mitigated
Limited impact if telnet is disabled and devices are isolated from untrusted networks.
🎯 Exploit Status
Exploitation requires sending specially crafted network packets to the telnet service. The hard-coded credentials bypass authentication entirely.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No vendor advisory found
Restart Required: No
Instructions:
1. Check vendor website for firmware updates
2. If update available, download and install via web interface
3. Verify telnet service is disabled after update
🔧 Temporary Workarounds
Disable telnet service
linuxCompletely disable the telnet daemon to prevent exploitation
telnetd -l /bin/sh -p 23 &
Block telnet port at firewall
linuxPrevent external access to telnet port 23
iptables -A INPUT -p tcp --dport 23 -j DROP
🧯 If You Can't Patch
- Isolate affected devices in separate VLAN with strict access controls
- Implement network segmentation to limit lateral movement potential
🔍 How to Verify
Check if Vulnerable:
Attempt telnet connection to port 23 and check if authentication is bypassed with known hard-coded credentialsCheck Version:
Check firmware version in router web interface or via serial consoleVerify Fix Applied:
Verify telnet service is not running on port 23 and cannot be accessed📡 Detection & Monitoring
Log Indicators:
- Failed telnet authentication attempts
- Successful telnet logins from unusual IPs
- Root shell access via telnet
Network Indicators:
- Telnet traffic to port 23
- Unusual outbound connections from router
- Command execution patterns in telnet sessions
SIEM Query:
source="router_logs" AND (event="telnet_login" OR port=23) AND (user="root" OR auth_success=true)