CVE-2025-22939
📋 TL;DR
A command injection vulnerability in the telnet service of Adtran 411 ONT devices allows unauthenticated attackers to execute arbitrary commands with root privileges. This affects organizations using vulnerable Adtran 411 ONT hardware with exposed telnet services.
💻 Affected Systems
- Adtran 411 ONT
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to intercept network traffic, deploy persistent backdoors, pivot to internal networks, or render devices inoperable.
Likely Case
Attackers gain root shell access to manipulate device configuration, steal credentials, or disrupt network services.
If Mitigated
Limited impact if telnet service is disabled or network access is restricted, though underlying vulnerability remains.
🎯 Exploit Status
Multiple public proof-of-concept demonstrations and detailed write-ups available. Exploitation requires minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: No
Instructions:
No official patch available. Check Adtran support portal for firmware updates. If update available: 1. Download firmware from vendor portal 2. Backup current configuration 3. Apply firmware update via management interface 4. Verify version update
🔧 Temporary Workarounds
Disable Telnet Service
allCompletely disable the vulnerable telnet service and use SSH or other secure management protocols instead.
# Configuration varies by device - consult Adtran documentation for disabling telnet
Network Access Control
linuxRestrict telnet access to trusted management networks using firewall rules.
# Example iptables rule: iptables -A INPUT -p tcp --dport 23 -s TRUSTED_NETWORK -j ACCEPT
# iptables -A INPUT -p tcp --dport 23 -j DROP
🧯 If You Can't Patch
- Isolate affected devices in separate VLAN with strict firewall rules
- Implement network monitoring for telnet traffic and command injection attempts
🔍 How to Verify
Check if Vulnerable:
Check if device is running version L80.00.0011.M2 and telnet service is enabled/accessible. Test with known exploit payloads in controlled environment.Check Version:
# Typically via web interface or CLI: show versionVerify Fix Applied:
Verify telnet service is disabled or inaccessible. Test that command injection attempts no longer succeed.📡 Detection & Monitoring
Log Indicators:
- Unusual telnet connections
- Suspicious command execution in system logs
- Multiple failed authentication attempts followed by successful command execution
Network Indicators:
- Telnet traffic to port 23 with unusual payloads
- Command injection patterns in telnet sessions
- Unexpected outbound connections from ONT devices
SIEM Query:
source="*telnet*" AND ("cmd=" OR "exec=" OR "system(" OR "$" OR "|")