ICS Advisory (ICSA-21-315-12)

Siemens NX JT Translator

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1. EXECUTIVE SUMMARY

  • CVSS v3 3.3
  • ATTENTION: Low attack complexity
  • Vendor: Siemens
  • Equipment: NX
  • Vulnerabilities: Out-of-bounds Read, Access of Uninitialized Pointer

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could lead to access violation and arbitrary code execution on the target host system.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Siemens reports these vulnerabilities affect the following NX design software products:

  • NX 1980 Series: All versions prior to v1984

3.2 VULNERABILITY OVERVIEW

3.2.1    OUT-OF-BOUNDS READ CWE-125

The affected application is vulnerable to an out-of-bounds read past the end of an allocated buffer when parsing JT files. An attacker could leverage this vulnerability to leak information in the context of the current process.

CVE-2021-41533 has been assigned to this vulnerability. A CVSS v3 base score of 3.3 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N).

3.2.2    ACCESS OF UNINITIALIZED POINTER CWE-824

The affected application is vulnerable to an out-of-bounds read past the end of an allocated buffer when parsing JT files. An attacker could leverage this vulnerability to leak information in the context of the current process.

CVE-2021-41534 has been assigned to this vulnerability. A CVSS v3 base score of 3.3 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N).

3.3 BACKGROUND

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

3.4 RESEARCHER

xina1i, working with Trend Micro’s Zero Day Initiative, reported these vulnerabilities to Siemens and CISA.

4. MITIGATIONS

Siemens has released an update for the NX 1980 Series and recommends users update to v1984 or later.

Siemens recommends users avoid opening untrusted files from unknown sources.

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 following the recommendations in the product manuals.

For more information about this issue, please see Siemens’ security advisory SSA-740908

CISA also recommends users take the following measures to protect themselves from social engineering attacks: 

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 these vulnerabilities. These vulnerabilities are not exploitable remotely.


Contact Information

For any questions related to this report, please contact the CISA at:

Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  https://us-cert.cisa.gov/ics 
or incident reporting:  https://us-cert.cisa.gov/report

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