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AUSCERT External Security Bulletin Redistribution
Advisory (icsa-20-014-03) Siemens SCALANCE X Switches
16 January 2020
AusCERT Security Bulletin Summary
Product: Siemens SCALANCE X Switches
Operating System: Network Appliance
Impact/Access: Unauthorised Access -- Remote/Unauthenticated
CVE Names: CVE-2019-13933
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ICS Advisory (ICSA-20-014-03)
Siemens SCALANCE X Switches
Original release date: January 14, 2020
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1. EXECUTIVE SUMMARY
o CVSS v3 8.8
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Siemens
o Equipment: SCALANCE X Switches
o Vulnerability: Missing Authentication for Critical Function
2. RISK EVALUATION
Successful exploitation of this vulnerability could allow an unauthenticated
attacker to violate access-control rules.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of SCALANCE X Switches, used to connect industrial
components, are affected:
o All versions of the SCALANCE X-200RNA switch family
o All versions prior to Version 4.1.3 of the SCALANCE X-300 switch family
(including SIPLUS NET variants)
o All versions prior to Versions 4.1.3 of the SCALANCE X-408
3.2 VULNERABILITY OVERVIEW
3.2.1 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
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/
o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Germany
Maxim Rupp reported this vulnerability to Siemens.
Siemens recommends the following workarounds and mitigations affected users can
apply to reduce risk:
For the SCALANCE X-200RNA switch family Siemens recommends:
o Configure ACLs to only allow Web-based management from trusted IP
o Disable web-based management (WBM) and use SSH to configure the device.
For the SCALANCE X-300 switch family (including SIPLUS NET variants), Siemens
recommends that users upgrade to Version 4.1.3
For the SCALANCE X-408, Siemens recommends that users upgrade to Version 4.1.3
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:
For more information see the Siemens security advisory .
CISA recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:
o Minimize network exposure for all control system devices and/or systems,
and ensure that they are not accessible from the Internet .
o Locate control system networks and remote devices behind firewalls, and
isolate them from the business network.
o When remote access is required, use secure methods, such as Virtual Private
Networks (VPNs), recognizing that VPNs may have vulnerabilities and should
be updated to the most current version available. Also recognize that VPN
is only as secure as the 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 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
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.
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