ICS Advisory (ICSA-20-014-03)

Siemens SCALANCE X Switches (Update B)

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1. EXECUTIVE SUMMARY

  • CVSS v3 8.8
  • ATTENTION: Exploitable remotely/low attack complexity
  • Vendor: Siemens
  • Equipment: SCALANCE X Switches
  • Vulnerability: Missing Authentication for Critical Function

2. UPDATE INFORMATION

This updated advisory is a follow-up to the advisory update titled ICSA-20-014-03 Siemens SCALANCE X Switches (Update A) that was published February 10, 2022, to the ICS webpage on cisa.gov/ics.

3. RISK EVALUATION

Successful exploitation of this vulnerability could allow an unauthenticated attacker to violate access-control rules.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

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

  • SCALANCE X-200RNA (HSA): All versions
  • SCALANCE X-200RNA (PRP): All versions
  • SCALANCE X-200RNA EEC (HSR): All versions
  • SCALANCE X-200RNA EEC (PRP): All versions

--------- Begin Update B Part 1 of 1 ---------

  • SCALANCE X302-7 EEC: All versions prior to v4.1.3 
  • SCALANCE X304-2FE: All versions prior to v4.1.3
  • SCALANCE X306-1LD FE: All versions prior to v4.1.3
  • SCALANCE X307-2 EEC: All versions prior to v4.1.3
  • SCALANCE X307-2: All versions prior to v4.1.3
  • SCALANCE X307-3: All versions prior to v4.1.3
  • SCALANCE X307-3LD: All versions prior to v4.1.3
  • SCALANCE X308-2: All versions prior to v4.1.3
  • SCALANCE X308-2LD: All versions prior to v4.1.3
  • SCALANCE X308-2LH: All versions prior to v4.1.3
  • SCALANCE X308-2LH+: All versions prior to v4.1.3
  • SCALANCE X308-2M: All versions prior to v4.1.3
  • SCALANCE X308-2M TS: All versions prior to v4.1.3
  • SCALANCE X310: All versions prior to v4.1.3
  • SCALANCE X310FE: All versions prior to v4.1.3
  • SCALANCE X320-1 FE: All versions prior to v4.1.3
  • SCALANCE X320-1-2LD FE: All versions prior to v4.1.3
  • SCALANCE X408-2: All versions prior to v4.1.3
  • SCALANCE XR324-4M EEC: All versions prior to v4.1.3
  • SCALANCE XR324-4M PoE: All versions prior to v4.1.3
  • SCALANCE XR324-12M: All versions prior to v4.1.3
  • SCALANCE XR324-12M TS: All versions prior to v4.1.3
  • SIPLUS NET SCALANCE X308-2: All versions prior to v4.1.3

--------- End Update B Part 1 of 1 ---------

4.2.1    MISSING AUTHENTICATION FOR CRITICAL FUNCTION CWE-306

This vulnerability could be exploited by an attacker with network access to the affected systems. An attacker could obtain sensitive information or change the device configuration.

CVE-2019-13933 has been assigned to this vulnerability. A CVSS v3 base score of 8.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L).

4.3 BACKGROUND

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

4.4 RESEARCHER

Maxim Rupp reported this vulnerability to Siemens.

5. MITIGATIONS

Siemens recommends the following workarounds and mitigations affected users can apply to reduce risk:

  • For the SCALANCE X-300 switch family (including X408 and SIPLUS NET variants) it is recommended that users upgrade to Version 4.1.3

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

  • Configure ACLs to only allow Web-based management from trusted IP addresses.
  • Disable web-based management (WBM) and use SSH to configure the device.

As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for industrial security and following recommendations in the product manuals.

Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage.

For more information see the Siemens Security Advisory SSA-443566

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/ics 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/ics 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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