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 v3 7.8
ATTENTION: Low attack complexity
Vendor: Siemens
Equipment: Parasolid
Vulnerabilities: Out-of-bounds Write

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to execute code in the context of the current process.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Siemens Parasolid, a 3D geometric modeling tool, are affected:

Parasolid V34.1: all versions prior to V34.1.258
Parasolid V35.0: all versions prior to V35.0.253
Parasolid V35.0: all versions prior to V35.0.260
Parasolid V35.1: all versions prior to V35.1.184
Parasolid V35.1: all versions prior to V35.1.246
Parasolid V36.0: all versions prior to V36.0.142
Parasolid V36.0: all versions prior to V36.0.156

3.2 Vulnerability Overview

3.2.1 OUT-OF-BOUNDS WRITE CWE-787

The affected application contains an out of bounds write past the end of an allocated structure while parsing specially crafted X_T files. This could allow an attacker to execute code in the context of the current process.

CVE-2023-41032 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.2 OUT-OF-BOUNDS WRITE CWE-787

The affected application contains an out of bounds write past the end of an allocated structure while parsing specially crafted X_T files. This could allow an attacker to execute code in the context of the current process.

CVE-2023-41033 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

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

Parasolid V34.1: Update to V34.1.258 or later version
Parasolid V35.0: Update to V35.0.253 or later version
Parasolid V35.1: Update to V35.1.184 or later version
Parasolid V36.0: Update to V36.0.142 or later version
Parasolid V35.0: Update to V35.0.260 or later version
Parasolid V35.1: Update to V35.1.246 or later version
Parasolid V36.0: Update to V36.0.156 or later version
Do not open untrusted X_T files in Parasolid

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-190839 in HTML and CSAF.

CISA recommends users take defensive measures to minimize the risk of exploitation of this (these) vulnerability(ies), 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 these vulnerabilities has been reported to CISA at this time. These vulnerabilities are not exploitable remotely.

5. UPDATE HISTORY

September 14, 2023: Initial Publication