CVE-2025-27020
📋 TL;DR
An improper SSH configuration in Infinera MTC-9 allows unauthenticated attackers to execute arbitrary commands and access the file system. This affects MTC-9 devices running R22.1.1.0275 up to versions before R23.0.
💻 Affected Systems
- Infinera MTC-9
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise leading to data theft, service disruption, and potential lateral movement within the network.
Likely Case
Unauthorized access to sensitive data and execution of malicious commands on affected devices.
If Mitigated
Limited impact if SSH is properly secured with authentication and network restrictions.
🎯 Exploit Status
Exploitation likely involves connecting to SSH with improper authentication settings.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: R23.0 or later
Vendor Advisory: https://www.cvcn.gov.it/cvcn/cve/CVE-2025-27020
Restart Required: Yes
Instructions:
1. Check current version with vendor-specific command. 2. Upgrade to R23.0 or later following Infinera's official upgrade procedures. 3. Restart the device as required.
🔧 Temporary Workarounds
Disable SSH or restrict access
linuxDisable SSH service if not needed, or restrict SSH access to trusted IPs only.
# Disable SSH: systemctl stop sshd; systemctl disable sshd
# Restrict SSH in sshd_config: AllowUsers user@trusted_ip
🧯 If You Can't Patch
- Implement strict network access controls to limit SSH traffic to trusted sources only.
- Monitor SSH logs for unauthorized access attempts and review file system integrity regularly.
🔍 How to Verify
Check if Vulnerable:
Check the device version; if it's R22.1.1.0275 or later but before R23.0, it is vulnerable.Check Version:
Use Infinera-specific CLI command to check firmware version (e.g., 'show version' or similar).Verify Fix Applied:
Verify the device version is R23.0 or later after patching.📡 Detection & Monitoring
Log Indicators:
- Failed SSH authentication attempts from unknown IPs
- Unusual command execution in SSH logs
Network Indicators:
- SSH connections from unexpected sources
- Anomalous outbound traffic post-SSH access
SIEM Query:
source="ssh_logs" AND (event="authentication failure" OR event="session opened") | stats count by src_ip