CVE-2024-20286
📋 TL;DR
This CVE describes a Python sandbox escape vulnerability in Cisco NX-OS Software that allows authenticated local attackers with Python execution privileges to break out of the restricted Python environment and execute arbitrary commands on the underlying operating system. It affects Cisco Nexus devices running vulnerable NX-OS versions with Python interpreter enabled.
💻 Affected Systems
- Cisco Nexus 9000 Series Switches
- Other Cisco NX-OS based devices with Python interpreter
📦 What is this software?
Nx Os by Cisco
⚠️ Risk & Real-World Impact
Worst Case
An authenticated attacker gains full control of the network device, potentially compromising the entire network segment, exfiltrating sensitive data, or using the device as a pivot point for lateral movement.
Likely Case
An insider or compromised account with Python privileges escapes the sandbox and executes limited commands with the authenticated user's permissions, potentially disrupting network operations or accessing sensitive configuration data.
If Mitigated
With proper access controls and monitoring, exploitation would be detected and contained, limiting impact to the specific device and preventing lateral movement.
🎯 Exploit Status
Exploitation requires authenticated access with Python execution privileges and knowledge of specific Python function manipulation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific fixed versions per product line
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-psbe-ce-YvbTn5du
Restart Required: Yes
Instructions:
1. Review Cisco advisory for affected versions. 2. Download and install the fixed NX-OS version for your device. 3. Schedule maintenance window for reboot. 4. Verify patch installation and functionality.
🔧 Temporary Workarounds
Disable Python execution privileges
cisco-nxosRemove Python execution privileges from users who don't require them for operational needs
configure terminal
username <username> no privilege python-script
Restrict user access
allImplement least privilege access controls and monitor users with Python execution capabilities
🧯 If You Can't Patch
- Implement strict access controls and monitor all users with Python execution privileges
- Segment network to limit potential lateral movement from compromised devices
🔍 How to Verify
Check if Vulnerable:
Check NX-OS version against affected versions in Cisco advisory and verify if Python interpreter is enabledCheck Version:
show version | include nxosVerify Fix Applied:
Verify installed NX-OS version is listed as fixed in Cisco advisory and test Python sandbox functionality📡 Detection & Monitoring
Log Indicators:
- Unusual Python script execution patterns
- Failed sandbox escape attempts in system logs
- Unexpected command execution from Python context
Network Indicators:
- Unusual outbound connections from network devices
- Anomalous configuration changes
SIEM Query:
Search for Python execution events followed by system command execution or privilege escalation attempts🔗 References
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-psbe-ce-YvbTn5du
- https://www.cisco.com/c/en/us/td/docs/dcn/nx-os/nexus9000/105x/programmability/cisco-nexus-9000-series-nx-os-programmability-guide-105x/m-n9k-python-api-101x.html?bookSearch=true#concept_A2CFF094ADCB414C983EA06AD8E9A410
