CVE-2024-20411
📋 TL;DR
This vulnerability in Cisco NX-OS Software allows authenticated local attackers with Bash shell access to execute arbitrary code with root privileges. It affects Cisco Nexus switches and MDS switches running vulnerable NX-OS versions. Attackers need existing local access and Bash shell privileges to exploit this.
💻 Affected Systems
- Cisco Nexus 3000 Series Switches
- Cisco Nexus 9000 Series Switches in standalone NX-OS mode
- Cisco Nexus 9500 R-Series Line Cards and Fabric Modules
- Cisco MDS 9000 Series Multilayer Switches
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing root-level arbitrary code execution, potentially leading to network disruption, data theft, or lateral movement.
Likely Case
Privilege escalation from authenticated user to root, enabling configuration changes, credential harvesting, or persistence mechanisms.
If Mitigated
Limited impact if proper access controls restrict Bash shell access and follow least privilege principles.
🎯 Exploit Status
Requires authenticated local access and Bash shell privileges. Exploitation involves executing specific crafted commands.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: NX-OS 10.4(3) and later
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-bshacepe-bApeHSx7
Restart Required: Yes
Instructions:
1. Check current NX-OS version with 'show version'. 2. Download appropriate 10.4(3) or later release from Cisco Software Center. 3. Follow standard NX-OS upgrade procedures. 4. Reboot device after upgrade.
🔧 Temporary Workarounds
Restrict Bash Shell Access
allLimit user access to Bash shell through role-based access control
configure terminal
role name restricted-role
rule 1 deny feature bash-shell
show role name restricted-role
🧯 If You Can't Patch
- Implement strict access controls to limit Bash shell access to essential personnel only
- Monitor and audit Bash shell usage through system logs and implement alerting for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Run 'show version' and check if NX-OS version is earlier than 10.4(3)Check Version:
show version | include NXOSVerify Fix Applied:
After upgrade, run 'show version' to confirm version is 10.4(3) or later📡 Detection & Monitoring
Log Indicators:
- Unusual Bash shell access patterns
- Commands executed with unexpected privilege escalation
- User privilege changes in system logs
Network Indicators:
- None - local exploitation only
SIEM Query:
source="nxos" AND (event="bash" OR event="shell") AND user!="authorized_users"