Siemens Mendix Excel Importer Module

1. EXECUTIVE SUMMARY

• CVSS v3 4.3
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Mendix, a subsidiary of Siemens
• Equipment: Mendix Excel Importer Module
• Vulnerability: Generation of Error Message Containing Sensitive Information

2. RISK EVALUATION

Successful exploitation of this vulnerability could expose information to unauthorized parties. 

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Mendix Excel Importer, a module that imports Excel data sheets into Mendix applications, are affected:

• Mendix Excel Importer Module: All versions prior to v9.0.3

3.2 VULNERABILITY OVERVIEW

3.2.1    GENERATION OF ERROR MESSAGE CONTAINING SENSITIVE INFORMATION CWE-209

Uploading a manipulated XML file results in an exception that could expose information about the application-server and the XML framework.

CVE-2021-31339 has been assigned to this vulnerability. A CVSS v3 base score of 4.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N).

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

Mendix has released an update for the Mendix Excel Importer module and recommends user update to v9.0.3 or a later version. 

As a general security measure, Siemens strongly recommends users protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends users configure the environment according to Siemens' operational guidelines for industrial security, and follow the recommendations in the product manual.

Additional information on industrial security by Siemens can be found at: https://www.siemens.com/industrialsecurity

For more information about this issue, please see Siemens security advisory SSA-854248

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 that they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
• 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 on us-cert.cisa.gov. Several recommended 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 on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.



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

No known public exploits specifically target this vulnerability.