CVE-2025-27394

Remediation/Mitigation Strategy for CVE-2025-27394

This document outlines the remediation and mitigation strategy for CVE-2025-27394, a vulnerability affecting Siemens SCALANCE LPE9403 devices.

1. Vulnerability Description:

  • CVE ID: CVE-2025-27394
  • Affected Product: SCALANCE LPE9403 (6GK5998-3GS00-2AC2)
  • Affected Versions: All versions prior to V4.0
  • Description: The affected SCALANCE LPE9403 devices lack proper sanitization of user input when creating new SNMP users. This vulnerability allows an authenticated, highly privileged remote attacker to execute arbitrary code on the device.

2. Severity:

  • CVSS v3.x Score: 8.6 (High)
  • CVSS Vector: This wasn’t provided in the original text, so we’ll construct one based on the description. We assume Attack Vector is Network (AV:N), Attack Complexity is Low (AC:L), Privileges Required is High (PR:H), User Interaction is None (UI:N), Scope is Changed (S:C), Confidentiality Impact is High (C:H), Integrity Impact is High (I:H), Availability Impact is High (A:H). This leads to: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
  • Impact: Remote Code Execution (RCE). Successful exploitation allows a remote attacker to gain complete control of the affected device. This could lead to:
    • Data breaches
    • Denial-of-service (DoS) attacks
    • Compromise of network infrastructure
    • Lateral movement within the network
    • Complete system compromise

3. Known Exploit Information:

  • The provided information indicates a potential for exploitation based on input sanitization, but does not explicitly state a public exploit. The CVSS score however, strongly suggests easy exploitation for users with valid credentials.
  • Based on the vulnerability description (lack of input sanitization), a proof-of-concept exploit could likely be developed to inject malicious commands into the SNMP user creation process. An attacker would need to be authenticated with highly privileged credentials (e.g., an administrator account) to create new SNMP users.
  • Important: Closely monitor security advisories, vulnerability databases, and threat intelligence feeds for public exploit information and indicators of compromise (IOCs) related to CVE-2025-27394.

4. Remediation Strategy:

  • Apply the Update: Upgrade the SCALANCE LPE9403 device to version V4.0 or later. Siemens has likely released a patch or firmware update that addresses this vulnerability. This is the primary remediation step. Consult the Siemens ProductCERT advisory and the Siemens Industry Online Support portal for the latest updates and instructions.
  • Testing: Before deploying the update in a production environment, thoroughly test the update in a non-production environment to ensure compatibility and stability and to verify that it successfully mitigates the vulnerability.

5. Mitigation Strategy (Until Update Can Be Applied):

If upgrading to V4.0 or later immediately is not feasible, implement the following mitigation measures:

  • Restrict Access to SNMP Management Interface:
    • Limit access to the SNMP management interface of the SCALANCE LPE9403 device to only authorized personnel and network segments. Implement strict firewall rules to block unauthorized access. Use access control lists (ACLs) on the device itself to limit which IP addresses can manage the device.
    • Regularly review and update the ACLs.
  • Enforce Strong Authentication:
    • Ensure that strong passwords are used for all user accounts with administrative privileges. Enforce password complexity requirements (e.g., minimum length, use of mixed-case letters, numbers, and special characters).
    • Implement multi-factor authentication (MFA) if supported by the device and management platform. While the exploit requires existing credentials, MFA can prevent credential theft in the first place.
  • Least Privilege Principle:
    • Apply the principle of least privilege. Grant users only the minimum necessary privileges required to perform their tasks. Avoid granting administrative privileges unnecessarily.
  • Monitor for Suspicious Activity:
    • Implement network intrusion detection systems (NIDS) and security information and event management (SIEM) systems to monitor network traffic and device logs for suspicious activity, such as:
      • Unusual SNMP traffic
      • Failed login attempts to the device’s management interface
      • Unexpected system processes or file modifications
      • Any other anomalies that may indicate exploitation
  • Disable SNMP if Not Required: If SNMP is not required for operational purposes, disable it on the SCALANCE LPE9403 device. This eliminates the attack vector entirely.
  • Input Validation: Though it doesn’t fix the underlying issue, if you have any ability to intercept SNMP user creation requests before they hit the SCALANCE device (e.g., through a management tool you’re using), perform your own input validation. Look for characters commonly used for command injection (e.g., ;, |, &, $, (, ), backticks). This is a highly imperfect and temporary measure, but it adds a small layer of defense.

6. Communication:

  • Communicate the vulnerability and the remediation/mitigation plan to all relevant stakeholders, including IT staff, network administrators, and security personnel.
  • Provide clear instructions on how to apply the update or implement the mitigation measures.

7. Post-Remediation/Mitigation Activities:

  • Verification: After applying the update or implementing the mitigation measures, verify that the vulnerability has been successfully addressed. This may involve penetration testing or vulnerability scanning.
  • Continuous Monitoring: Continuously monitor the SCALANCE LPE9403 device and network for any signs of compromise or suspicious activity.
  • Regular Security Assessments: Conduct regular security assessments to identify and address any new vulnerabilities.

8. Disclaimer:

This remediation/mitigation strategy is based on the information provided and current best practices. It is essential to consult the official Siemens documentation and security advisories for the most up-to-date information and guidance. The effectiveness of these measures depends on the specific configuration of your environment.

Assigner

Date

  • Published Date: 2025-03-11 09:48:25
  • Updated Date: 2025-03-11 10:15:19

More Details

CVE-2025-27394