ICS Advisory (ICSA-22-104-13)

Siemens SIMATIC S7-1500 CPU GNU/Linux subsystem

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1. EXECUTIVE SUMMARY

  • CVSS v3 9.8
  • ATTENTION: Exploitable remotely/low attack complexity
  • Vendor: Siemens
  • Equipment: SIMATIC S7-1500 CPU GNU/Linux subsystem
  • Vulnerabilities: Use of Unmaintained Third-party Components

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could crash the device being accessed; a buffer overflow condition may allow remote code execution.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Siemens reports these vulnerabilities affect the GNU/Linux subsystem of the following products: 

  • SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant): firmware v2.9.4
  • SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant): firmware v2.9.3
  • SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant): firmware v2.8.4
  • SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant): firmware versions up to and including v2.6.1
  • SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant): firmware versions prior to v2.6.0

3.2 VULNERABILITY OVERVIEW

3.2.1    USE OF UNMAINTAINED THIRD-PARTY COMPONENTS CWE-1104

GNU/Linux vulnerabilities have been identified. For a full list of the identified vulnerabilities, please see Siemens SSB-439005

3.3 BACKGROUND

  • CRITICAL INFRASTRUCTURE SECTORS: Chemical, Critical Manufacturing, Energy, Food and Agriculture, Water and Wastewater Systems
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

Siemens is working on an update for the latest firmware version, and recommends the following mitigations:

For more information about these vulnerabilities and the associated mitigations, please see SSB-439005

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 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 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 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.

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

No known public exploits specifically target these vulnerabilities. 


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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