Siemens Mendix Encryption Module

As of January 10, 2023, CISA will no longer be updating ICS security advisories for Siemens product vulnerabilities beyond the initial advisory. For the most up-to-date information on vulnerabilities in this advisory, please see Siemens' ProductCERT Security Advisories (CERT Services | Services | Siemens Global).

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1. EXECUTIVE SUMMARY

• CVSS v4 8.7
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Siemens
• Equipment: Mendix Encryption
• Vulnerability: Use of Hard-coded, Security-relevant Constants

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to decrypt any encrypted project data.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following products of Siemens are affected:

• Mendix Encryption: Versions V10.0.0 and prior

3.2 Vulnerability Overview

3.2.1 USE OF HARD-CODED, SECURITY-RELEVANT CONSTANTS CWE-547

Affected versions of the module define a specific hard-coded default value for the EncryptionKey constant, which is used in projects where no individual EncryptionKey was specified. This could allow to an attacker to decrypt any encrypted project data, as the default encryption key can be considered compromised.

CVE-2024-39888 has been assigned to this vulnerability. A CVSS v3.1 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

A CVSS v4 score has also been calculated for CVE-2024-39888. A base score of 8.7 has been calculated; the CVSS vector string is (CVSS4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

Siemens recommends users update to the latest version:

• Mendix Encryption: Update to V10.0.2 or later version

As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens' operational guidelines for industrial security and following recommendations in the product manuals.

Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage

For more information see the associated Siemens security advisory SSA-998949 in HTML and CSAF.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:

• Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
• Locate control system networks and remote devices behind firewalls and isolating them from business networks.
• When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.

No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.

5. UPDATE HISTORY

• July 11, 2024: Initial Publication

• Siemens