CVE-2020-3298
📋 TL;DR
An unauthenticated remote attacker can cause Cisco ASA and FTD devices to reload by sending malformed OSPF packets, resulting in denial of service. This affects devices running vulnerable versions of Cisco ASA Software and Firepower Threat Defense Software with OSPF enabled. Network traffic traversing affected devices will be disrupted during the reload.
💻 Affected Systems
- Cisco Adaptive Security Appliance (ASA) Software
- Cisco Firepower Threat Defense (FTD) Software
📦 What is this software?
Adaptive Security Appliance Software by Cisco
View all CVEs affecting Adaptive Security Appliance Software →
Adaptive Security Appliance Software by Cisco
View all CVEs affecting Adaptive Security Appliance Software →
Adaptive Security Appliance Software by Cisco
View all CVEs affecting Adaptive Security Appliance Software →
Adaptive Security Appliance Software by Cisco
View all CVEs affecting Adaptive Security Appliance Software →
Adaptive Security Appliance Software by Cisco
View all CVEs affecting Adaptive Security Appliance Software →
⚠️ Risk & Real-World Impact
Worst Case
Persistent attacker causes repeated device reloads, creating extended network outages and disrupting all traffic through the firewall.
Likely Case
Intermittent DoS attacks causing periodic service disruptions and potential network instability.
If Mitigated
Minimal impact with proper network segmentation, OSPF authentication, and monitoring in place.
🎯 Exploit Status
Exploitation requires sending specially crafted OSPF packets to vulnerable devices. No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in ASA 9.12.4.38, 9.13.1.21, 9.14.1.18, and later releases
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-ospf-dos-RhMQY8qx
Restart Required: Yes
Instructions:
1. Check current ASA/FTD version with 'show version'. 2. Download appropriate fixed version from Cisco Software Center. 3. Follow Cisco upgrade procedures for ASA/FTD devices. 4. Reboot device after upgrade.
🔧 Temporary Workarounds
Disable OSPF
allIf OSPF is not required, disable it completely to eliminate the attack surface
no router ospf [process-id]
Implement OSPF Authentication
allConfigure OSPF MD5 or SHA authentication to prevent unauthorized OSPF packets
area [area-id] authentication message-digest
ip ospf message-digest-key [key-id] md5 [key]
Implement ACLs
allUse access control lists to restrict OSPF traffic to trusted sources only
access-list OSPF-ACL permit ospf host [trusted-neighbor] any
access-list OSPF-ACL deny ospf any any
🧯 If You Can't Patch
- Disable OSPF routing protocol if not essential for network operations
- Implement strict network segmentation to isolate OSPF traffic and limit attack surface
🔍 How to Verify
Check if Vulnerable:
Check if OSPF is enabled: 'show running-config | include router ospf'. Check version: 'show version | include Version'Check Version:
show version | include VersionVerify Fix Applied:
Verify upgraded to fixed version: 'show version | include Version'. Confirm version matches patched releases.📡 Detection & Monitoring
Log Indicators:
- Unexpected device reloads
- OSPF protocol errors
- Memory allocation failures in system logs
Network Indicators:
- Unusual OSPF packet patterns
- OSPF traffic from unexpected sources
- Repeated device reloads
SIEM Query:
source="asa" OR source="ftd" (reload OR crash OR "%ASA-" AND (ospf OR memory))