CVE-2024-20271
📋 TL;DR
An unauthenticated remote attacker can send specially crafted IPv4 packets to Cisco Access Points, causing them to crash and reload, resulting in denial of service. This affects Cisco APs running vulnerable software versions. The attacker does not need to be associated with the AP to exploit this vulnerability.
💻 Affected Systems
- Cisco Access Points
📦 What is this software?
Ios Xe by Cisco
Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...
Learn more about Ios Xe →Ios Xe by Cisco
Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...
Learn more about Ios Xe →Ios Xe by Cisco
Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...
Learn more about Ios Xe →Ios Xe by Cisco
Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...
Learn more about Ios Xe →⚠️ Risk & Real-World Impact
Worst Case
Critical network disruption with multiple APs crashing simultaneously, causing widespread wireless service outage.
Likely Case
Individual APs periodically reloading, causing intermittent wireless connectivity issues for users.
If Mitigated
Minimal impact with proper network segmentation and monitoring detecting attack attempts.
🎯 Exploit Status
Attack requires sending crafted IPv4 packets to or through affected device. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific fixed versions
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ap-dos-h9TGGX6W
Restart Required: Yes
Instructions:
1. Check Cisco advisory for affected versions. 2. Download and install fixed software version from Cisco. 3. Reboot affected access points. 4. Verify patch installation.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to AP management interfaces
ACL Filtering
allImplement ACLs to filter suspicious IPv4 traffic to APs
🧯 If You Can't Patch
- Implement strict network segmentation to isolate APs from untrusted networks
- Deploy intrusion prevention systems to detect and block crafted IPv4 packets
🔍 How to Verify
Check if Vulnerable:
Check AP software version against Cisco advisory affected versions listCheck Version:
show version (on Cisco AP CLI)Verify Fix Applied:
Verify AP is running fixed software version from Cisco advisory📡 Detection & Monitoring
Log Indicators:
- AP reload events
- Unexpected reboots
- Crash dump files
Network Indicators:
- Unusual IPv4 traffic patterns to APs
- Crafted packet detection
SIEM Query:
Search for 'reload' or 'crash' events from Cisco AP logs