CVE-2023-20154
📋 TL;DR
This vulnerability allows an unauthenticated remote attacker to bypass authentication in Cisco Modeling Labs and gain administrative access to the web interface. It affects systems using external authentication servers, requiring valid credentials from that server. Attackers could then modify simulations and user data.
💻 Affected Systems
- Cisco Modeling Labs
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full administrative compromise of the web interface, enabling attackers to access, modify, or delete all simulations and user data, potentially disrupting operations and causing data loss.
Likely Case
Unauthorized administrative access leading to data theft, configuration changes, or service disruption, especially if external authentication is misconfigured or credentials are compromised.
If Mitigated
Limited impact if systems are patched, use strong authentication controls, or are isolated from untrusted networks, reducing the risk of exploitation.
🎯 Exploit Status
Exploitation depends on having valid credentials from the external authentication server and specific server responses.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Cisco advisory for patched versions; update to the latest recommended release.
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cml-auth-bypass-4fUCCeG5
Restart Required: Yes
Instructions:
1. Review the Cisco advisory for affected versions. 2. Download and apply the latest software update from Cisco. 3. Restart the Cisco Modeling Labs service or server as required. 4. Verify the patch is applied successfully.
🔧 Temporary Workarounds
Disable External Authentication
allTemporarily disable the external authentication mechanism to prevent exploitation until patching is complete.
Consult Cisco documentation for specific commands to disable external authentication in Cisco Modeling Labs configuration.
🧯 If You Can't Patch
- Isolate affected systems from untrusted networks, especially the internet, to reduce remote attack surface.
- Implement strict access controls and monitoring for authentication logs to detect and respond to suspicious login attempts.
🔍 How to Verify
Check if Vulnerable:
Check the Cisco Modeling Labs version against the advisory; if using external authentication and unpatched, assume vulnerable.Check Version:
Use the Cisco Modeling Labs web interface or CLI commands (e.g., 'show version') to check the current software version.Verify Fix Applied:
After patching, verify the software version matches the patched release and test authentication to ensure no bypass occurs.📡 Detection & Monitoring
Log Indicators:
- Unusual administrative login events, especially from unexpected IP addresses or with external authentication errors.
Network Indicators:
- Suspicious HTTP requests to the web interface authentication endpoints.
SIEM Query:
Example: 'source="cml_logs" AND event_type="authentication" AND result="success" AND user_role="admin"' to monitor for admin logins.