ICS Advisory (ICSA-20-042-07)

Siemens SCALANCE X Switches

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1. EXECUTIVE SUMMARY

  • CVSS v3 4.2
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: Siemens
  • Equipment: SCALANCE X switches
  • Vulnerability: Protection Mechanism Failure

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to perform administrative actions.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of SCALANCE X Switches, used to connect industrial components, are affected:

  • SCALANCE X-200 switch family (including SIPLUS NET variants): All versions prior to Version 5.2.4
  • SCALANCE X-200IRT switch family (including SIPLUS NET variants): All versions
  • SCALANCE X-300 switch family (including X408 and SIPLUS NET variants): All versions prior to Version 4.1.3

3.2 VULNERABILITY OVERVIEW

3.2.1    PROTECTION MECHANISM FAILURE CWE-693

The device does not send the X-Frame-Option header in the administrative web interface, which makes it vulnerable to click-jacking attacks.

CVE-2019-13924 has been assigned to this vulnerability. A CVSS v3 base score of 4.2 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:L).

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

Siemens has released updates, which are recommended to be applied when possible:

  • SCALANCE X-200 switch family (including SIPLUS NET variants): Version 5.2.4
  • SCALANCE X-300 switch family (including X408 and SIRPLUS NET variants): Version 4.1.3

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

  • Only access links from trusted sources in the browser you use to configure the SCALANCE X switches.

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 more information see Siemens security advisory SSA-951513

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

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


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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