CVE-2022-20714
📋 TL;DR
This vulnerability allows unauthenticated remote attackers to cause Cisco ASR 9000 Series routers with Lightspeed-Plus line cards to reset by sending specially crafted IPv4 or IPv6 packets. This results in denial of service for traffic traversing the affected line card. Organizations using these specific Cisco routers are affected.
💻 Affected Systems
- Cisco ASR 9000 Series Aggregation Services Routers with Lightspeed-Plus line cards
📦 What is this software?
Ios Xr by Cisco
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service for all traffic passing through affected line cards, potentially disrupting critical network infrastructure and services.
Likely Case
Intermittent line card resets causing service disruptions, packet loss, and network instability for affected traffic flows.
If Mitigated
Limited impact with proper network segmentation, traffic filtering, and monitoring in place to detect and block malicious packets.
🎯 Exploit Status
Exploitation requires sending packets through the device, not just to it. Attackers need to be able to route traffic through vulnerable line cards.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Cisco IOS XR Software Release 7.5.3 or later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lsplus-Z6AQEOjk
Restart Required: Yes
Instructions:
1. Download appropriate Cisco IOS XR software version 7.5.3 or later. 2. Schedule maintenance window. 3. Backup current configuration. 4. Install new software following Cisco upgrade procedures. 5. Reboot affected routers. 6. Verify functionality.
🔧 Temporary Workarounds
Access Control List Filtering
allImplement ACLs to filter suspicious traffic patterns that might trigger the vulnerability
ipv4 access-list BLOCK-MALFORMED
ipv6 access-list BLOCK-MALFORMED-V6
Traffic Rate Limiting
allApply rate limiting to control plane traffic to reduce impact of potential attacks
control-plane
service-policy input COPP-POLICY
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected routers from untrusted networks
- Deploy intrusion prevention systems to detect and block malformed packet attacks
🔍 How to Verify
Check if Vulnerable:
Check router configuration for Lightspeed-Plus line cards and verify IOS XR version is below 7.5.3Check Version:
show version | include Cisco IOS XRVerify Fix Applied:
Verify IOS XR version is 7.5.3 or later and monitor for line card resets📡 Detection & Monitoring
Log Indicators:
- Line card reset events in system logs
- Unexpected hardware failures
- Increased error counters on interfaces
Network Indicators:
- Sudden traffic drops on specific interfaces
- Increased latency through affected paths
- Routing protocol flaps
SIEM Query:
source="cisco-router" ("line card reset" OR "LC.*reset" OR "hardware failure")