Technical Analysis of CVE-2024-50375: Missing Authentication for Critical Function in Advantech EKI Series Devices

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2024-50375 CWE: CWE-306 – Missing Authentication for Critical Function CVSS v3.1 Score: 9.8 (Critical) – (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Severity Breakdown:

• Attack Vector (AV:N): Network-exploitable, allowing remote attackers to interact with the vulnerable service without physical access.
• Attack Complexity (AC:L): Low – Exploitation requires no specialized conditions or user interaction.
• Privileges Required (PR:N): None – No authentication is required to exploit the flaw.
• User Interaction (UI:N): None – Exploitation occurs without any user action.
• Scope (S:U): Unchanged – The impact is confined to the vulnerable component.
• Confidentiality (C:H): High – Unauthorized access to sensitive device configurations, credentials, or network traffic.
• Integrity (I:H): High – Attackers may modify device settings, firmware, or network configurations.
• Availability (A:H): High – Potential for denial-of-service (DoS) or complete device takeover.

Risk Assessment:

This vulnerability is critical due to its remote, unauthenticated, and low-complexity exploitation potential. It poses a severe risk to industrial control systems (ICS), operational technology (OT), and enterprise networks where Advantech EKI devices are deployed. Successful exploitation could lead to lateral movement, data exfiltration, or disruption of critical infrastructure.

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2. Potential Attack Vectors and Exploitation Methods

Exploitation Pathway:

The vulnerability resides in the default "edgserver" service, which lacks proper authentication mechanisms for critical functions. An attacker can exploit this flaw by:

1. Network Scanning & Discovery:

   • Use tools like Nmap, Masscan, or Shodan to identify exposed Advantech EKI devices with the edgserver service running (default port: TCP/80 or TCP/443).
   • Example Nmap scan:

     nmap -p 80,443 --script http-title <target_IP> -oN eki_scan.txt
     

2. Unauthenticated API/Service Interaction:

   • The edgserver service likely exposes REST APIs, SOAP endpoints, or proprietary protocols that allow configuration changes, firmware updates, or administrative actions without authentication.
   • Attackers may send crafted HTTP/HTTPS requests to:
     • Dump device configurations (e.g., Wi-Fi passwords, VPN settings, SNMP communities).
     • Modify network settings (e.g., VLANs, routing tables, firewall rules).
     • Upload malicious firmware (leading to persistent backdoors).
     • Execute arbitrary commands (if command injection is possible).

3. Proof-of-Concept (PoC) Exploitation:

   • A hypothetical exploit might involve:

     POST /api/config HTTP/1.1
     Host: <target_IP>
     Content-Type: application/json
     
     {
       "action": "set_config",
       "params": {
         "admin_password": "hacked123",
         "enable_ssh": true
       }
     }
     

   • If the service processes this request without authentication, the attacker gains full administrative control.

4. Post-Exploitation Impact:

   • Lateral Movement: Compromised devices can be used as pivot points to attack other systems on the same network.
   • Data Exfiltration: Sensitive industrial or enterprise data may be extracted.
   • Denial-of-Service (DoS): Misconfiguration or firmware corruption could render the device inoperable.
   • Persistence: Malicious firmware or backdoors may survive reboots.

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3. Affected Systems and Software Versions

Vulnerable Devices:

Device Model	Affected Firmware Versions	Fixed Version (if available)
EKI-6333AC-2G	≤ v1.6.3	TBD (Check Advantech advisories)
EKI-6333AC-2GD	≤ v1.6.3	TBD
EKI-6333AC-1GPO	≤ v1.2.1	TBD

Device Context:

• Advantech EKI Series are industrial-grade wireless access points (APs) and routers used in:
  • Industrial IoT (IIoT) environments (manufacturing, energy, utilities).
  • Smart city infrastructure (traffic systems, surveillance).
  • Enterprise networks (remote offices, warehouses).
• These devices often operate in OT/ICS networks, where security misconfigurations can have catastrophic consequences.

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4. Recommended Mitigation Strategies

Immediate Actions (Short-Term):

1. Network Segmentation & Isolation:

   • Restrict access to the edgserver service using firewalls, VLANs, or ACLs.
   • Block inbound traffic from untrusted networks (e.g., the internet) to the device’s management interface.
   • Disable remote management if not required.

2. Disable Unnecessary Services:

   • If the edgserver service is not critical, disable it via the device’s web interface or CLI.
   • Example (if CLI access is available):

     config set edgserver disable
     save
     reboot
     

3. Apply Workarounds:

   • Change default credentials (if applicable) and enforce strong password policies.
   • Enable HTTPS (if available) to encrypt management traffic.
   • Monitor network traffic for unusual activity (e.g., unexpected API calls to edgserver).

4. Temporary Compensating Controls:

   • Deploy an IPS/IDS (e.g., Snort, Suricata) to detect and block exploitation attempts.
   • Use a reverse proxy (e.g., Nginx, HAProxy) to enforce authentication before forwarding requests to the device.

Long-Term Remediation:

1. Firmware Updates:

   • Monitor Advantech’s security advisories for patched firmware versions.
   • Test and deploy updates in a non-production environment before applying to critical systems.

2. Vendor Engagement:

   • Contact Advantech support for official patches or mitigation guidance.
   • Request a CVE-specific advisory if none is publicly available.

3. Security Hardening:

   • Disable unused services (e.g., Telnet, FTP, SNMPv2).
   • Enable logging and SIEM integration to detect suspicious activity.
   • Conduct penetration testing to verify remediation.

4. Zero Trust Implementation:

   • Enforce least-privilege access for device management.
   • Implement multi-factor authentication (MFA) for administrative interfaces.

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5. Impact on the Cybersecurity Landscape

Broader Implications:

1. Industrial & Critical Infrastructure Risk:

   • Advantech EKI devices are commonly deployed in OT environments, where exploitation could lead to:
     • Physical damage (e.g., disrupted manufacturing processes).
     • Safety hazards (e.g., compromised SCADA systems).
     • Regulatory violations (e.g., NERC CIP, IEC 62443).

2. Supply Chain & Third-Party Risk:

   • Many organizations outsource network management to third-party vendors who may deploy vulnerable devices.
   • Supply chain attacks could leverage this flaw to compromise multiple downstream customers.

3. Exploitability in the Wild:

   • Given the CVSS 9.8 rating, this vulnerability is highly attractive to threat actors, including:
     • APT groups (e.g., state-sponsored actors targeting critical infrastructure).
     • Ransomware operators (e.g., LockBit, Black Basta) for initial access.
     • Botnet herders (e.g., Mirai variants) for DDoS amplification.

4. Compliance & Legal Risks:

   • Organizations failing to patch may violate industry regulations (e.g., GDPR, HIPAA, NIST SP 800-53).
   • Liability concerns if exploitation leads to data breaches or operational disruptions.

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6. Technical Details for Security Professionals

Root Cause Analysis:

• CWE-306 (Missing Authentication for Critical Function) indicates that the edgserver service does not enforce authentication for sensitive operations.
• Likely causes:
  • Hardcoded or default credentials (if authentication exists but is bypassable).
  • Improper access control (e.g., missing Authorization header checks in API endpoints).
  • Legacy code where authentication was never implemented.

Exploitation Technical Deep Dive:

1. Service Discovery:

   • The edgserver service typically listens on TCP/80 (HTTP) or TCP/443 (HTTPS).
   • Shodan query to find exposed devices:

     http.title:"Advantech EKI" port:80,443
     

2. API Enumeration:

   • Use Burp Suite, OWASP ZAP, or Postman to interact with the service.
   • Common vulnerable endpoints may include:
     • /api/config (read/write device settings).
     • /api/firmware (upload malicious firmware).
     • /api/reboot (trigger DoS).

3. Proof-of-Concept (PoC) Exploit:

   • A simple Python script to test for the vulnerability:

     import requests
     
     target = "http://<TARGET_IP>/api/config"
     headers = {"Content-Type": "application/json"}
     payload = {
         "action": "set_config",
         "params": {
             "admin_password": "exploited",
             "ssh_enabled": True
         }
     }
     
     response = requests.post(target, json=payload, headers=headers)
     print(response.text)
     

   • If the response contains a success message, the device is vulnerable.

4. Post-Exploitation Techniques:

   • Dump device configurations (e.g., GET /api/config).
   • Modify network settings to redirect traffic (e.g., DNS hijacking).
   • Upload malicious firmware (e.g., via POST /api/firmware).
   • Establish persistence (e.g., enable SSH with a backdoor account).

Detection & Forensics:

1. Network-Based Detection:

   • SIEM Rules (e.g., Splunk, QRadar):

     index=network (dest_port=80 OR dest_port=443) AND (http_method=POST OR http_method=PUT) AND uri_path="/api/*"
     

   • Snort/Suricata Rule:

     alert tcp any any -> $HOME_NET 80 (msg:"Possible CVE-2024-50375 Exploitation - Unauthenticated API Access"; flow:to_server,established; content:"/api/config"; http_uri; content:"POST"; http_method; classtype:attempted-admin; sid:1000001; rev:1;)
     

2. Endpoint Detection:

   • Monitor for unusual process execution (e.g., curl, wget interacting with edgserver).
   • Check for unexpected firmware updates or configuration changes.

3. Forensic Artifacts:

   • Logs (if enabled) may show unauthenticated API calls.
   • Network captures (PCAPs) can reveal exploitation attempts.
   • Memory forensics (if available) may show injected payloads.

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Conclusion & Recommendations

CVE-2024-50375 represents a critical, remotely exploitable vulnerability in Advantech EKI devices, posing severe risks to industrial and enterprise networks. Given its CVSS 9.8 score, organizations must prioritize mitigation efforts to prevent exploitation.

Key Takeaways for Security Teams:

✅ Immediately isolate vulnerable devices from untrusted networks. ✅ Disable the edgserver service if not required. ✅ Monitor for exploitation attempts using SIEM and IDS/IPS. ✅ Apply vendor patches as soon as they become available. ✅ Conduct a full security audit of all Advantech devices in the environment.

Long-Term Strategies:

• Adopt a zero-trust architecture for OT/ICS networks.
• Implement continuous vulnerability scanning for IoT/IIoT devices.
• Engage in threat intelligence sharing to stay ahead of emerging exploits.

Failure to address this vulnerability could result in catastrophic breaches, operational disruptions, or regulatory penalties. Security teams should treat this as a top-priority incident response scenario.

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References:

• Nozomi Networks Advisory
• CWE-306: Missing Authentication for Critical Function
• Advantech Security Advisories