CVE-2025-20261
📋 TL;DR
This vulnerability allows authenticated remote attackers to bypass SSH restrictions on Cisco UCS servers' IMC, gaining elevated privileges to access internal services. Attackers could create new administrator accounts or make unauthorized system modifications. Affected systems include Cisco UCS B-Series, C-Series, S-Series, and X-Series servers with vulnerable IMC software.
💻 Affected Systems
- Cisco UCS B-Series Servers
- Cisco UCS C-Series Servers
- Cisco UCS S-Series Servers
- Cisco UCS X-Series Servers
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker creating persistent administrator accounts, modifying configurations, and potentially accessing sensitive data or launching further attacks.
Likely Case
Unauthorized administrative access leading to configuration changes, service disruption, and potential lateral movement within the network.
If Mitigated
Limited impact if proper network segmentation, access controls, and monitoring are in place to detect and block exploitation attempts.
🎯 Exploit Status
Exploitation requires valid SSH credentials and knowledge of crafted syntax. No public exploit code available at time of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific fixed versions
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-ssh-priv-esc-2mZDtdjM
Restart Required: Yes
Instructions:
1. Review Cisco advisory for affected versions. 2. Download appropriate firmware update from Cisco Software Center. 3. Apply update to Cisco IMC via web interface or CLI. 4. Reboot affected servers to complete installation.
🔧 Temporary Workarounds
Restrict SSH Access
allLimit SSH access to Cisco IMC to trusted management networks only
Implement Network Segmentation
allIsolate management interfaces from general network access
🧯 If You Can't Patch
- Implement strict network access controls to limit SSH access to Cisco IMC interfaces
- Monitor SSH authentication logs for unusual access patterns or failed login attempts
🔍 How to Verify
Check if Vulnerable:
Check Cisco IMC firmware version via web interface (System > Firmware) or CLI (show version)Check Version:
show version | include IMCVerify Fix Applied:
Verify firmware version matches patched version from Cisco advisory and test SSH access with restricted commands📡 Detection & Monitoring
Log Indicators:
- Unusual SSH connections to Cisco IMC
- Multiple failed SSH login attempts followed by successful login
- Administrative account creation via SSH
Network Indicators:
- SSH traffic to Cisco IMC from unexpected sources
- Unusual SSH command patterns
SIEM Query:
source="cisco-imc" AND (event="ssh_login" OR event="account_creation")