CVE-2025-27396

CVE-2025-27396: Privilege Escalation in Siemens SCALANCE LPE9403

This document outlines a remediation and mitigation strategy for CVE-2025-27396, a privilege escalation vulnerability in Siemens SCALANCE LPE9403 devices.

1. Vulnerability Description

  • CVE ID: CVE-2025-27396
  • Affected Product: Siemens SCALANCE LPE9403 (6GK5998-3GS00-2AC2)
  • Affected Versions: All versions prior to V4.0
  • Description: The affected devices fail to adequately restrict the elevation of privileges needed to execute legitimate functions. This weakness allows a remote attacker, with valid low-privilege credentials, to escalate their privileges on the system.

2. Severity Assessment

  • CVSS v3 Score: 8.8 (High)
  • CVSS v3 Vector: AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • Explanation:
    • AV:N (Network): The vulnerability is exploitable over the network.
    • AC:L (Low): The attack requires minimal effort and no special conditions to succeed.
    • PR:L (Low): The attacker needs only low-level privileges to exploit the vulnerability.
    • UI:N (None): No user interaction is required for the exploit.
    • S:U (Unchanged): An exploited vulnerability results in complete compromise of the resource managed by the same security authority.
    • C:H (High): The attacker gains complete access to confidential data.
    • I:H (High): The attacker can completely compromise system integrity, modifying or deleting critical data.
    • A:H (High): The attacker can cause a complete denial of service, making the system unusable.
  • Severity Level: High

3. Known Exploits

  • Exploit Status: At the time of this document, no publicly available exploit code is known. However, the vulnerability details are disclosed, making it easier for attackers to develop exploits. The absence of a public exploit does not mean the risk is low. It is crucial to remediate this vulnerability promptly.

4. Remediation and Mitigation Strategy

This strategy employs a layered approach, prioritizing immediate actions to reduce risk while implementing long-term solutions.

A. Immediate Actions (Within 24-48 hours):

  1. Inventory and Identification:

    • Identify all SCALANCE LPE9403 devices (6GK5998-3GS00-2AC2) on the network.
    • Determine the firmware version running on each device. This is critical to identifying vulnerable systems.
    • Document the location and function of each device.

  2. Network Segmentation:

    • Isolate affected devices on a separate network segment if possible. This limits the potential impact of a successful exploit by restricting lateral movement. Implement firewall rules to limit communication between the affected segment and other critical network segments.
    • Consider placing vulnerable devices behind a VPN, requiring authentication for access.

  3. Access Control Hardening:

    • Review User Accounts: Thoroughly review all user accounts on the SCALANCE LPE9403 devices. Identify and disable or remove any unnecessary or default accounts.
    • Enforce Strong Passwords: Ensure all remaining user accounts have strong, unique passwords. Enforce password complexity policies.
    • Least Privilege Principle: Grant only the minimum necessary privileges to each user account. Revoke any excessive permissions.
    • Multi-Factor Authentication (MFA): If supported by the device, enable multi-factor authentication for all user accounts, especially those with administrative privileges.

  4. Intrusion Detection and Monitoring:

    • Configure intrusion detection systems (IDS) and security information and event management (SIEM) systems to monitor network traffic to and from affected devices.
    • Implement alerts for suspicious activity, such as privilege escalation attempts, unauthorized access, and unusual network traffic patterns.
    • Monitor device logs for unusual activity and failed login attempts.

B. Short-Term Actions (Within 1-2 weeks):

  1. Firmware Upgrade:

    • Crucially, upgrade to the latest version of the SCALANCE LPE9403 firmware (V4.0 or later). This is the primary solution to address the vulnerability. Obtain the firmware from the official Siemens website or authorized channels.
    • Thoroughly test the updated firmware in a non-production environment before deploying it to production devices.
    • Follow Siemens’ recommended upgrade procedures carefully.

  2. Configuration Review:

    • Review the configuration of each SCALANCE LPE9403 device to ensure it aligns with security best practices.
    • Disable any unnecessary services or features.
    • Harden the device configuration according to Siemens’ security recommendations.

  3. Vulnerability Scanning:

    • Perform regular vulnerability scans on the affected devices to identify any other potential vulnerabilities.

C. Long-Term Actions (Ongoing):

  1. Security Awareness Training:

    • Provide regular security awareness training to employees and contractors who manage or have access to SCALANCE LPE9403 devices. Emphasize the importance of strong passwords, recognizing phishing attempts, and reporting suspicious activity.

  2. Patch Management:

    • Establish a robust patch management process to ensure that all devices are promptly updated with the latest security patches.

  3. Network Security Architecture Review:

    • Conduct a comprehensive review of the network security architecture to identify any weaknesses and implement improvements.
    • Consider implementing a zero-trust security model.

  4. Vendor Communication:

    • Maintain regular communication with Siemens to stay informed about new security threats and updates for SCALANCE LPE9403 devices.

5. Rollback Plan

  • Before applying any updates, create a full backup of the device configuration.
  • If the firmware upgrade causes unexpected issues, restore the device to its previous configuration using the backup.
  • Thoroughly document any problems encountered during the upgrade process.
  • Have a contingency plan in place to restore services if a device fails after the update.

6. Communication Plan

  • Inform relevant stakeholders (e.g., IT staff, management, affected users) about the vulnerability and the remediation plan.
  • Provide regular updates on the progress of the remediation efforts.
  • Establish a communication channel for reporting any issues or concerns related to the vulnerability.

7. Disclaimer

This document provides general guidance for remediating CVE-2025-27396. The specific actions required may vary depending on the organization’s unique environment and risk tolerance. Consult with security professionals and Siemens’ documentation for specific recommendations. Always thoroughly test updates in a non-production environment before deploying them to production systems.

Assigner

Date

  • Published Date: 2025-03-11 09:48:27
  • Updated Date: 2025-03-11 10:15:19

More Details

CVE-2025-27396