CVE-2018-0314
📋 TL;DR
This critical vulnerability in Cisco Fabric Services allows unauthenticated remote attackers to execute arbitrary code on affected devices by sending maliciously crafted packets. It affects multiple Cisco networking products including Firepower firewalls, Nexus switches, and UCS fabric interconnects when configured to use Cisco Fabric Services.
💻 Affected Systems
- Firepower 4100 Series Next-Generation Firewalls
- Firepower 9300 Security Appliance
- MDS 9000 Series Multilayer Switches
- Nexus 2000 Series Fabric Extenders
- Nexus 3000 Series Switches
- Nexus 3500 Platform Switches
- Nexus 5500 Platform Switches
- Nexus 5600 Platform Switches
- Nexus 6000 Series Switches
- Nexus 7000 Series Switches
- Nexus 7700 Series Switches
- Nexus 9000 Series Switches in standalone NX-OS mode
- Nexus 9500 R-Series Line Cards and Fabric Modules
- UCS 6100 Series Fabric Interconnects
- UCS 6200 Series Fabric Interconnects
- UCS 6300 Series Fabric Interconnects
📦 What is this software?
Unified Computing System Firmware by Cisco
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of affected device allowing attacker to execute arbitrary code, pivot to other systems, and maintain persistent access to the network.
Likely Case
Remote code execution leading to device compromise, data exfiltration, and potential lateral movement within the network.
If Mitigated
Limited impact if proper network segmentation and access controls prevent unauthorized access to Cisco Fabric Services ports.
🎯 Exploit Status
Exploitation requires sending specially crafted Cisco Fabric Services packets to vulnerable devices.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Cisco Security Advisory for specific fixed versions per product
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-fx-os-fabric-execution
Restart Required: Yes
Instructions:
1. Review Cisco Security Advisory for affected versions. 2. Download and apply appropriate patches from Cisco Software Center. 3. Reboot affected devices after patching. 4. Verify patch installation and system stability.
🔧 Temporary Workarounds
Disable Cisco Fabric Services
allDisable Cisco Fabric Services if not required for network operations
no feature cfs
Restrict Access to CFS Ports
allImplement access control lists to restrict access to Cisco Fabric Services ports
access-list 100 deny tcp any any eq 3225
access-list 100 deny udp any any eq 3225
access-list 100 permit ip any any
🧯 If You Can't Patch
- Disable Cisco Fabric Services on all affected devices
- Implement strict network segmentation and firewall rules to block access to CFS ports (TCP/UDP 3225)
🔍 How to Verify
Check if Vulnerable:
Check if Cisco Fabric Services is enabled: 'show feature | include cfs' and verify device model/version against Cisco advisoryCheck Version:
show versionVerify Fix Applied:
Verify patch installation: 'show version' and confirm version is not vulnerable per Cisco advisory📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes
- Memory corruption errors
- Unauthorized configuration changes
Network Indicators:
- Unusual traffic to/from TCP/UDP port 3225
- Malformed Cisco Fabric Services packets
SIEM Query:
source_port:3225 OR dest_port:3225 AND (protocol:TCP OR protocol:UDP) AND (event_type:anomaly OR event_type:exploit)🔗 References
- http://www.securityfocus.com/bid/104516
- http://www.securitytracker.com/id/1041169
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-fx-os-fabric-execution
- http://www.securityfocus.com/bid/104516
- http://www.securitytracker.com/id/1041169
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180620-fx-os-fabric-execution
