CVE-2020-3243
📋 TL;DR
Multiple vulnerabilities in Cisco UCS Director and UCS Director Express for Big Data REST API allow remote attackers to bypass authentication or conduct directory traversal attacks. This affects systems running vulnerable versions of these Cisco management products. Successful exploitation could lead to unauthorized access and remote code execution.
💻 Affected Systems
- Cisco UCS Director
- Cisco UCS Director Express for Big Data
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attacker gains full administrative control, executes arbitrary code, and compromises the entire UCS management infrastructure.
Likely Case
Attackers bypass authentication to access sensitive configuration data, perform directory traversal to read arbitrary files, and potentially execute limited commands.
If Mitigated
With proper network segmentation and access controls, impact limited to isolated management network segment.
🎯 Exploit Status
Multiple public exploit scripts available. Authentication bypass and directory traversal are straightforward to exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.7.4.0 and later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucsd-mult-vulns-UNfpdW4E
Restart Required: Yes
Instructions:
1. Download patch from Cisco Software Center. 2. Backup current configuration. 3. Apply patch via UCS Director admin interface. 4. Restart services or appliance as required.
🔧 Temporary Workarounds
Restrict REST API Access
linuxLimit network access to UCS Director REST API endpoints using firewall rules.
iptables -A INPUT -p tcp --dport 443 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
Disable Unused REST Endpoints
linuxDisable specific REST API endpoints not required for operations.
Modify /opt/infra/webapps/ROOT/WEB-INF/web.xml to restrict endpoints
🧯 If You Can't Patch
- Isolate UCS Director appliance in dedicated management VLAN with strict access controls.
- Implement network-based intrusion detection to monitor for exploitation attempts.
🔍 How to Verify
Check if Vulnerable:
Check UCS Director version via admin interface: System > About. If version is below 6.7.4.0, system is vulnerable.Check Version:
ssh admin@ucs-director 'cat /opt/infra/version.properties'Verify Fix Applied:
Verify version is 6.7.4.0 or higher in System > About. Test REST API authentication requirements.📡 Detection & Monitoring
Log Indicators:
- Unauthenticated REST API requests to sensitive endpoints
- Multiple failed authentication attempts followed by successful access
- Unusual file access patterns in /opt/infra/logs/
Network Indicators:
- Unusual REST API traffic patterns
- Requests to /cloupia/script or other vulnerable endpoints without authentication
SIEM Query:
source="ucs-director" AND (uri_path="/cloupia/*" OR status_code=200) AND auth_status="failed"🔗 References
- http://packetstormsecurity.com/files/157955/Cisco-UCS-Director-Cloupia-Script-Remote-Code-Execution.html
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucsd-mult-vulns-UNfpdW4E
- https://www.zerodayinitiative.com/advisories/ZDI-20-540/
- http://packetstormsecurity.com/files/157955/Cisco-UCS-Director-Cloupia-Script-Remote-Code-Execution.html
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucsd-mult-vulns-UNfpdW4E
- https://www.zerodayinitiative.com/advisories/ZDI-20-540/
