CVE-2020-3470
📋 TL;DR
CVE-2020-3470 allows unauthenticated remote attackers to execute arbitrary code with root privileges on Cisco Integrated Management Controller (IMC) systems by sending crafted HTTP requests. This affects organizations using vulnerable Cisco UCS and IMC products. The vulnerability stems from improper boundary checks in the API subsystem.
💻 Affected Systems
- Cisco Integrated Management Controller (IMC)
- Cisco UCS C-Series Rack Servers
- Cisco UCS E-Series Servers
- Cisco UCS S-Series Servers
📦 What is this software?
Enterprise Nfv Infrastructure Software by Cisco
View all CVEs affecting Enterprise Nfv Infrastructure Software →
Integrated Management Controller by Cisco
Integrated Management Controller by Cisco
Integrated Management Controller by Cisco
Integrated Management Controller by Cisco
Integrated Management Controller by Cisco
Integrated Management Controller by Cisco
Integrated Management Controller by Cisco
Integrated Management Controller by Cisco
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root-level code execution, allowing attackers to install persistent malware, steal sensitive data, or pivot to other network systems.
Likely Case
Remote code execution leading to data exfiltration, system disruption, or ransomware deployment on affected Cisco IMC systems.
If Mitigated
Limited impact if systems are patched, network segmentation is implemented, and API access is restricted to trusted sources only.
🎯 Exploit Status
Exploitation requires sending crafted HTTP requests to the IMC API endpoint, which is straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.1(3a) and later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-api-rce-UXwpeDHd
Restart Required: Yes
Instructions:
1. Download the patched firmware version 4.1(3a) or later from Cisco's support site. 2. Log into the IMC web interface. 3. Navigate to Admin > Firmware Management. 4. Upload and install the new firmware. 5. Reboot the system after installation completes.
🔧 Temporary Workarounds
Restrict API Access
linuxLimit network access to the IMC API subsystem using firewall rules or access control lists.
iptables -A INPUT -p tcp --dport 443 -s trusted_ip_range -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
Disable Unused API Features
allDisable unnecessary API endpoints in IMC configuration if not required for operations.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate IMC systems from untrusted networks.
- Deploy intrusion detection systems (IDS) to monitor for exploit attempts against the IMC API.
🔍 How to Verify
Check if Vulnerable:
Check the IMC firmware version via the web interface (Admin > Firmware Management) or CLI command: show versionCheck Version:
show versionVerify Fix Applied:
Confirm firmware version is 4.1(3a) or later using the same methods, and test that API functionality remains operational.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /api/* endpoints
- Multiple failed authentication attempts followed by successful API calls
- Log entries showing buffer overflow errors in IMC logs
Network Indicators:
- HTTP traffic to IMC API endpoints from unexpected source IPs
- Unusually large HTTP requests to IMC systems
- Traffic patterns matching known exploit signatures
SIEM Query:
source="cimc_logs" AND (http_method="POST" AND uri_path="/api/*" AND (content_length>10000 OR status_code=500))