ICS Advisory

Siemens SIMATIC ITC

Last Revised
Alert Code
ICSA-21-350-12

1. EXECUTIVE SUMMARY

  • CVSS v3 9.8
  • ATTENTION: Exploitable remotely/low attack complexity
  • Vendor: Siemens
  • Equipment: SIMATIC ITC Products
  • Vulnerabilities: Using Components with Known Vulnerabilities

2. RISK EVALUATION

Successful exploitation of these LibVNC vulnerabilities could allow remote code execution, information disclosure, and denial-of-service attacks.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Siemens reports these vulnerabilities affect the following SIMATIC Industrial Thin Clients:

  • SIMATIC ITC1500 V3: All versions prior to v3.2.1.0
  • SIMATIC ITC1500 V3 PRO: All versions prior to v3.2.1.0
  • SIMATIC ITC1900 V3: All versions prior to v3.2.1.0
  • SIMATIC ITC1900 V3 PRO: All versions prior to v3.2.1.0
  • SIMATIC ITC2200 V3: All versions prior to v3.2.1.0
  • SIMATIC ITC2200 V3 PRO: All versions prior to v3.2.1.0

3.2 VULNERABILITY OVERVIEW

3.2.1    USING COMPONENTS WITH KNOWN VULNERABILITIES CWE-1035

Multiple LibVNC vulnerabilities in the affected products could allow remote code execution, information disclosure, and denial-of-service attacks under certain conditions.

CVE-2017-18922, CVE-2018-20019, CVE-2018-20748, CVE-2018-20749, CVE-2018-20750, CVE-2018-21247, CVE-2019-15681, CVE-2019-15690, CVE-2019-20788, CVE-2019-20839, CVE-2019-20840, CVE-2020-14396, CVE-2020-14397, CVE-2020-14398, CVE-2020-14401, CVE-2020-14402, CVE-2020-14403, CVE-2020-14404, CVE-2020-14405 have been assigned to these vulnerabilities. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

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 has released updates for the affected products and recommends users update to the latest versions:

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

  • Monitor and restrict access to Port 5900/TCP to trusted IP addresses only

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 to configure 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 at: https://www.siemens.com/industrialsecurity

Please see Siemens’ security advisory SSA-390195 for more information.

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.

No known public exploits specifically target these vulnerabilities. 

This product is provided subject to this Notification and this Privacy & Use policy.

Vendor

  • Siemens

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