Siemens Mendix SAML 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).

1. EXECUTIVE SUMMARY

• CVSS v3 9.1
• ATTENTION: Exploitable remotely / low attack complexity 
• Vendor: Siemens 
• Equipment: Mendix SAML Module 
• Vulnerability: Incorrect Implementation of Authentication Algorithm 

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow unauthenticated remote attackers to bypass authentication and gain access to the application. 

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following software from Siemens is affected: 

• Mendix SAML (Mendix 7 compatible): Versions 1.16.4 to 1.17.2 
• Mendix SAML (Mendix 8 compatible): Versions 2.2.0 to 2.2.3 
• Mendix SAML (Mendix 9 compatible, New Track): Versions 3.1.9 to 3.2.5 
• Mendix SAML (Mendix 9 compatible, Upgrade Track): Version 3.1.9 to 3.2.5 

3.2 VULNERABILITY OVERVIEW

3.2.1 INCORRECT IMPLEMENTATION OF AUTHENTICATION ALGORITHM CWE-303 

The affected versions of the module insufficiently verify the SAML assertions. This could allow unauthenticated remote attackers to bypass authentication and get access to the application. 

CVE-2023-25957 has been assigned to this vulnerability. A CVSS v3 base score of 9.1 has been calculated; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N). 

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens reported this vulnerability to CISA. 

4. MITIGATIONS

Siemens has identified the following specific workarounds and mitigations users can apply to reduce risk: 

• Mendix SAML (Mendix 9 compatible): Update to V3.3.0 or later version 
• Mendix SAML (Mendix 8 compatible): Update to V2.3.0 or later version 
• Mendix SAML (Mendix 7 compatible): Update to V1.17.3 or later version 
• "Use Encryption" setting should be set to "On" in the SAML module setting. 

As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens' operational guidelines for industrial security, and to follow the recommendations in the product manuals. Additional information on industrial security by Siemens can be found on the Siemens website.

For further inquiries on security vulnerabilities in Siemens products and solutions, users should contact the Siemens ProductCERT.  

For more information, see the associated Siemens security advisory SSA-851884 in HTML and CSAF. 

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls and isolate them from business networks.
• When remote access is required, use 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 its 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 at 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.

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 exploits specifically target this vulnerability.