CVE-2024-20304
📋 TL;DR
This vulnerability in Cisco IOS XR Software allows unauthenticated remote attackers to send crafted Mtrace2 packets that exhaust UDP packet memory, causing denial of service. Affected devices become unable to process UDP-based protocols, disrupting network services. Organizations using vulnerable Cisco IOS XR versions are at risk.
💻 Affected Systems
- Cisco IOS XR Software
📦 What is this software?
Ios Xr by Cisco
Ios Xr by Cisco
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Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
Ios Xr by Cisco
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service where affected devices cannot process any UDP traffic, potentially disrupting critical network services and causing extended outages.
Likely Case
Intermittent service degradation as UDP packet memory is exhausted, affecting UDP-dependent applications and protocols on the device.
If Mitigated
Minimal impact if Mtrace2 is disabled or devices are properly segmented from untrusted networks.
🎯 Exploit Status
Exploitation requires sending crafted packets to vulnerable devices, which is relatively straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Cisco advisory for specific fixed releases
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-pak-mem-exhst-3ke9FeFy
Restart Required: Yes
Instructions:
1. Review Cisco advisory for affected versions. 2. Download and apply appropriate fixed software release. 3. Reboot affected devices after patching. 4. Verify patch installation and functionality.
🔧 Temporary Workarounds
Disable Mtrace2 feature
cisco-ios-xrDisable the multicast traceroute version 2 feature to prevent exploitation
no mtrace2
Implement ACL restrictions
cisco-ios-xrRestrict access to Mtrace2 ports from untrusted networks
access-list 100 deny udp any any eq 33434
access-list 100 permit ip any any
🧯 If You Can't Patch
- Segment vulnerable devices from untrusted networks using firewalls or VLANs
- Implement rate limiting on UDP traffic to affected devices
🔍 How to Verify
Check if Vulnerable:
Check IOS XR version and Mtrace2 configuration status using 'show version' and 'show running-config | include mtrace2'Check Version:
show versionVerify Fix Applied:
Verify updated version matches fixed releases in Cisco advisory and confirm Mtrace2 is disabled or patched📡 Detection & Monitoring
Log Indicators:
- High UDP packet drops
- Memory exhaustion alerts
- Mtrace2-related error messages
Network Indicators:
- Unusual volume of UDP traffic to port 33434
- Crafted Mtrace2 packets from suspicious sources
SIEM Query:
source_port:33434 AND protocol:UDP AND (packet_size:anomalous OR source_ip:blacklist)