CVE-2020-3167
📋 TL;DR
This vulnerability allows authenticated local attackers to execute arbitrary commands on Cisco FXOS and UCS Manager systems through insufficient input validation in the CLI. Attackers can craft malicious arguments to specific commands, gaining OS-level access with the privileges of the currently logged-in user (or root on UCS 6400 Series). Only users with local CLI access are affected.
💻 Affected Systems
- Cisco FXOS Software
- Cisco UCS Manager Software
📦 What is this software?
Adaptive Security Appliance Software by Cisco
View all CVEs affecting Adaptive Security Appliance Software →
Adaptive Security Appliance Software by Cisco
View all CVEs affecting Adaptive Security Appliance Software →
Adaptive Security Appliance Software by Cisco
View all CVEs affecting Adaptive Security Appliance Software →
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with root privileges on UCS 6400 Series Fabric Interconnects, allowing complete control over network infrastructure and potential lateral movement.
Likely Case
Privilege escalation from authenticated user to OS-level command execution, enabling data theft, configuration changes, or persistence mechanisms.
If Mitigated
Limited impact if proper access controls restrict local CLI access to trusted administrators only.
🎯 Exploit Status
Requires authenticated local access and knowledge of vulnerable CLI commands. No public exploit code available at advisory publication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Cisco Security Advisory for specific fixed versions
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200226-fxos-ucs-cmdinj
Restart Required: Yes
Instructions:
1. Review Cisco Security Advisory for affected versions. 2. Upgrade to fixed software releases. 3. Apply patches following Cisco's upgrade procedures. 4. Reboot affected systems as required.
🔧 Temporary Workarounds
Restrict CLI Access
allLimit local CLI access to trusted administrators only using role-based access controls.
Monitor CLI Usage
allImplement logging and monitoring of CLI commands for suspicious patterns.
🧯 If You Can't Patch
- Implement strict access controls to limit local CLI access to essential personnel only
- Enable comprehensive logging and monitoring of CLI sessions for detection of exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check software version against affected versions listed in Cisco Security AdvisoryCheck Version:
show version (Cisco CLI command)Verify Fix Applied:
Verify software version has been updated to fixed release specified in advisory📡 Detection & Monitoring
Log Indicators:
- Unusual CLI command patterns
- Commands with unexpected arguments
- Privilege escalation attempts
Network Indicators:
- None - local exploitation only
SIEM Query:
Search for CLI command logs containing suspicious argument patterns or privilege escalation indicators