CVE-2023-20056
📋 TL;DR
This vulnerability allows authenticated local attackers to cause Cisco access points to reboot by submitting specially crafted CLI commands. It affects Cisco APs running vulnerable software versions. Attackers need local access and authentication to exploit this DoS 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
Persistent DoS attacks could render access points unusable, disrupting wireless network connectivity for extended periods.
Likely Case
Temporary service disruption causing access points to reboot, resulting in brief wireless network outages.
If Mitigated
Minimal impact with proper access controls and monitoring in place to detect and prevent exploitation attempts.
🎯 Exploit Status
Requires authenticated local access; exploitation is straightforward once authenticated.
🛠️ 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-cli-dos-tc2EKEpu
Restart Required: Yes
Instructions:
1. Review Cisco advisory for affected versions 2. Download and apply appropriate firmware update 3. Reboot affected access points 4. Verify update successful
🔧 Temporary Workarounds
Restrict CLI Access
allLimit CLI access to trusted administrators only using AAA controls
aaa new-model
aaa authentication login default local
aaa authorization exec default local
Monitor CLI Sessions
allEnable logging and monitoring of CLI sessions for suspicious activity
logging buffered 51200
logging console
logging monitor
🧯 If You Can't Patch
- Implement strict access controls to limit who can access AP CLI
- Monitor for unexpected AP reboots and investigate any suspicious CLI activity
🔍 How to Verify
Check if Vulnerable:
Check AP software version against affected versions in Cisco advisoryCheck Version:
show versionVerify Fix Applied:
Verify AP is running patched firmware version from Cisco advisory📡 Detection & Monitoring
Log Indicators:
- Unexpected AP reboots
- Multiple failed CLI authentication attempts
- Suspicious CLI command patterns
Network Indicators:
- Sudden loss of wireless connectivity from specific APs
- AP reboot events
SIEM Query:
search 'AP reboot' OR 'CLI authentication failed' OR 'unexpected reload'