CVE-2020-3173
📋 TL;DR
This vulnerability allows authenticated local attackers to execute arbitrary commands on Cisco UCS Manager devices through the local management CLI. Attackers can exploit insufficient input validation by crafting malicious arguments to specific commands. Affected users include anyone with local access to Cisco UCS Manager systems, with Cisco UCS 6400 Series Fabric Interconnects being particularly vulnerable as commands execute with root privileges.
💻 Affected Systems
- Cisco UCS Manager Software
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root-level access on UCS 6400 Series, allowing attackers to install persistent backdoors, exfiltrate sensitive data, or disrupt operations.
Likely Case
Privilege escalation leading to unauthorized access to sensitive configuration data, network manipulation, or lateral movement within the infrastructure.
If Mitigated
Limited impact due to restricted local access, proper network segmentation, and monitoring of CLI activities.
🎯 Exploit Status
Exploitation requires authenticated local access to the CLI and knowledge of specific vulnerable commands. The advisory does not mention public exploits, but the low complexity suggests weaponization is possible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Cisco UCS Manager Software Release 4.0(4a) and later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200226-ucs-cli-cmdinj
Restart Required: Yes
Instructions:
1. Download the patched version (4.0(4a) or later) from Cisco's software download center. 2. Follow Cisco's upgrade procedures for UCS Manager. 3. Reboot affected devices after installation. 4. Verify the upgrade was successful.
🔧 Temporary Workarounds
Restrict Local CLI Access
allLimit physical and logical access to the local management CLI to only authorized administrators.
Implement Least Privilege
allEnsure users have only the minimum necessary privileges for their roles to limit potential damage.
🧯 If You Can't Patch
- Implement strict access controls to limit who can access the local management CLI.
- Monitor CLI sessions and command logs for suspicious activity or unusual command arguments.
🔍 How to Verify
Check if Vulnerable:
Check the UCS Manager version via the CLI: 'show version system' and verify if it's below 4.0(4a).Check Version:
show version systemVerify Fix Applied:
After patching, run 'show version system' to confirm the version is 4.0(4a) or higher.📡 Detection & Monitoring
Log Indicators:
- Unusual CLI command sequences
- Commands with unexpected or crafted arguments
- Privilege escalation attempts in system logs
Network Indicators:
- Unusual outbound connections from UCS Manager devices
- Anomalous traffic patterns following CLI sessions
SIEM Query:
source="ucs_manager" AND (event_type="cli_command" AND command_args CONTAINS suspicious_pattern)