CVE-2025-20163
📋 TL;DR
This vulnerability allows unauthenticated remote attackers to impersonate Cisco NDFC-managed devices via SSH man-in-the-middle attacks due to insufficient host key validation. Attackers could intercept SSH traffic and capture user credentials. Organizations using Cisco Nexus Dashboard Fabric Controller are affected.
💻 Affected Systems
- Cisco Nexus Dashboard Fabric Controller (NDFC)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain administrative access to network infrastructure, capture credentials, modify configurations, and potentially pivot to other systems.
Likely Case
Credential theft leading to unauthorized access to managed devices and potential network disruption.
If Mitigated
Limited impact with proper network segmentation, monitoring, and SSH key management.
🎯 Exploit Status
Requires man-in-the-middle position on SSH connections. No public exploit code known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Cisco advisory for specific fixed versions
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ndfc-shkv-snQJtjrp
Restart Required: Yes
Instructions:
1. Review Cisco advisory for fixed versions. 2. Backup current configuration. 3. Apply NDFC software update. 4. Restart NDFC services. 5. Verify SSH connections to managed devices.
🔧 Temporary Workarounds
Restrict SSH Access
allLimit SSH connections to NDFC-managed devices using network ACLs and firewall rules
Monitor SSH Connections
allImplement network monitoring for unusual SSH connection patterns or MITM indicators
🧯 If You Can't Patch
- Implement strict network segmentation to isolate NDFC SSH traffic
- Deploy certificate-based authentication and SSH key validation monitoring
🔍 How to Verify
Check if Vulnerable:
Check NDFC version against Cisco advisory. Verify SSH host key validation is properly configured.Check Version:
show version (in NDFC CLI)Verify Fix Applied:
Confirm NDFC is running patched version. Test SSH connections to managed devices validate host keys.📡 Detection & Monitoring
Log Indicators:
- Failed SSH host key validations
- Unusual SSH connection sources/timing
- Multiple SSH connection attempts
Network Indicators:
- SSH traffic interception patterns
- Unexpected SSH certificate changes
- MITM attack signatures
SIEM Query:
source="ndfc" AND (event="ssh_failure" OR event="host_key_mismatch")