ICS Advisory (ICSA-19-162-04)

Siemens SCALANCE X (Update A)

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1. EXECUTIVE SUMMARY

  • CVSS v3 7.1
  • ATTENTION: Low skill level to exploit
  • Vendor: Siemens
  • Equipment: SCALANCE X Switches
  • Vulnerability: Storing Passwords in a Recoverable Format

2. UPDATE INFORMATION

This updated advisory is a follow-up to the original advisory titled ICSA-19-162-04 Siemens SCALANCE X that was published June 11, 2019, to the ICS webpage on us-cert.gov.

3. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to reconstruct passwords for users of the affected devices, if the attacker is able to obtain a backup of the device configuration.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

The following Siemens SCALANCE X products are affected by this vulnerability: 

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  • SCALANCE X-200 switch family (including SIPLUS NET variants): all versions prior to v5.2.4
  • SCALANCE X-200IRT switch family (including SIPLUS NET variants): all versions
  • SCALANCE X-300 switch family (including SIPLUS NET variants): all versions prior to v4.1.3

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  • SCALANCE X-414-3E: all versions

4.2 VULNERABILITY OVERVIEW

4.2.1    STORING PASSWORDS IN A RECOVERABLE FORMAT CWE-257

The affected devices store passwords in a recoverable format. An attacker may extract and recover device passwords from the device configuration. Successful exploitation requires access to a device configuration backup and impacts confidentiality of the stored passwords.

CVE-2019-6567 has been assigned to this vulnerability. A CVSS v3 base score of 7.1 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N).

4.3 BACKGROUND

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

4.4 RESEARCHER

Christopher Wade from Pen Test Partners coordinated disclosure with Siemens; Siemens reported this vulnerability to CISA.

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Artem Zinenko from Kaspersky reported that SIPLUS should also be mentioned.

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5. MITIGATIONS

Siemens has identified the following specific workarounds/mitigations to reduce the risk from this vulnerability: 

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  • SCALANCE X-200 switch family (including SIPLUS NET variants): Update to v5.2.4
  • SCALANCE X-300 switch family (including SIPLUS NET variants): Update to v4.1.3
  • SCALANCE X-200IRT switch family (including SIPLUS NET variants): See recommendations following

--------- End Update A Part 3 of 3 ---------

  • SCALANCE X-414-3E: Migrate to the SCALANCE XM-400 product line

Until additional updates are available, Siemens recommends users apply the following workarounds/mitigations to reduce the risk from this vulnerability: 

  • Restrict access to configuration backups or archived device configuration data; 
  • Restrict or disable network access to mechanisms that allow retrieval of device configuration, if enabled.
  • Restrict access to device configuration module C-PLUG, if in use.

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 manuals.

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

For further inquiries on security vulnerabilities in Siemens products and solutions, please contact Siemens ProductCERT.

For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-646841

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.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.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. This vulnerability is not exploitable remotely.


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