CVE-2025-27493

Remediation/Mitigation Strategy for CVE-2025-27493

Vulnerability Description:

  • CVE ID: CVE-2025-27493
  • Product: Siemens SiPass integrated AC5102 (ACC-G2) and SiPass integrated ACC-AP
  • Affected Versions: All versions prior to V6.4.9
  • Description: The affected devices improperly sanitize user input for specific commands on the telnet command line interface. This allows an authenticated local administrator to escalate privileges by injecting arbitrary commands that are executed with root privileges. Essentially, the system trusts input from an authenticated administrator without proper validation, leading to command injection.

Severity:

  • CVSS v3 Score: 9.3 (Critical)
  • CVSS v3 Vector: AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H (Based on reported values)
    • AV:L (Attack Vector: Local) - Exploitable only with local access.
    • AC:L (Attack Complexity: Low) - Attack is easily exploitable.
    • PR:H (Privileges Required: High) - Requires high privileges (local administrator).
    • UI:N (User Interaction: None) - No user interaction required.
    • S:C (Scope: Changed) - Vulnerable component can affect resources beyond its security scope.
    • C:H (Confidentiality: High) - Complete loss of confidentiality.
    • I:H (Integrity: High) - Complete loss of integrity.
    • A:H (Availability: High) - Complete loss of availability.

Known Exploit:

The specific commands and injection methods are not explicitly detailed in the provided information. However, the vulnerability description indicates that a local administrator can leverage the telnet interface. It can be reasonably assumed that a proof-of-concept exploit could be developed to inject commands via the telnet CLI. Therefore, assume that the vulnerability can be readily exploited.

Remediation/Mitigation Strategy:

The primary and recommended remediation strategy is to apply the official Siemens security update.

  1. Apply the Security Update:

    • Action: Upgrade SiPass integrated AC5102 (ACC-G2) and SiPass integrated ACC-AP to version V6.4.9 or later.
    • Priority: Critical. This is the most effective way to address the vulnerability.
    • Procedure: Follow the official Siemens upgrade instructions for the SiPass integrated system. Ensure you have a proper backup before upgrading. Contact Siemens support if you need assistance.
    • Verification: After the update, verify the system version to confirm the patch has been applied successfully. Test the telnet interface with known exploit attempts (in a safe, controlled environment, if possible) to ensure the vulnerability is resolved.

  2. Temporary Mitigation Measures (If immediate patching is not possible):

    If an immediate upgrade to V6.4.9 or later is not feasible, implement the following mitigations:

    • Disable Telnet Access:
      • Action: Disable the telnet service on the affected devices. This will prevent exploitation via this interface.
      • Priority: High. This eliminates the attack vector until patching is possible.
      • Procedure: Access the system’s configuration and disable the telnet service. Document the process.
      • Considerations: Disabling telnet might impact legitimate administrative tasks. Ensure alternative, more secure methods of administration (e.g., SSH, web interface) are available. Communicate the change to administrators.
    • Restrict Telnet Access (If disabling is not possible):
      • Action: If telnet cannot be disabled, restrict access to the telnet service to only authorized IP addresses.
      • Priority: Medium. Limits the exposure to only specific trusted networks/hosts.
      • Procedure: Configure firewall rules on the device or network to restrict telnet access (port 23) to a limited set of IP addresses.
      • Considerations: Requires careful planning and implementation to avoid disrupting legitimate administrative activities.
    • Monitor System Logs:
      • Action: Implement enhanced monitoring of system logs on the affected devices. Look for suspicious activity related to command execution or privilege escalation.
      • Priority: Medium. Provides early warning of potential exploitation attempts.
      • Procedure: Configure logging to capture detailed information about telnet sessions, command execution, and user activity. Implement alerts for suspicious events.
      • Considerations: Requires appropriate log management infrastructure and expertise to analyze the logs effectively.
    • Principle of Least Privilege:
      • Action: Review and enforce the principle of least privilege for all accounts on the affected systems.
      • Priority: Low. Reduces the impact of a successful exploit.
      • Procedure: Ensure that users only have the minimum necessary privileges to perform their assigned tasks. Restrict access to sensitive resources.

Long-Term Recommendations:

  • Regular Security Audits: Conduct regular security audits of the SiPass integrated system to identify and address potential vulnerabilities.
  • Vulnerability Management Program: Implement a comprehensive vulnerability management program to proactively identify and address vulnerabilities in all systems.
  • Stay Informed: Subscribe to security advisories from Siemens and other relevant sources to stay informed about new vulnerabilities and security updates.
  • Secure Configuration Practices: Implement secure configuration practices for all systems, including the SiPass integrated system.

Communication Plan:

  • Inform all affected stakeholders (system administrators, security team, management) about the vulnerability and the remediation/mitigation plan.
  • Provide regular updates on the progress of the remediation effort.

Rollback Plan:

  • Before applying the security update, create a full system backup.
  • If the update causes unexpected issues, revert to the backup.
  • Thoroughly test and document the update process to ensure a smooth rollback if needed.

Assigner

Date

  • Published Date: 2025-03-11 09:48:33
  • Updated Date: 2025-03-11 10:15:20

More Details

CVE-2025-27493