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AUSCERT External Security Bulletin Redistribution
ESB-2019.3149
US-CERT Advisory (icsa-19-227-03) Siemens SCALANCE Products
16 August 2019
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AusCERT Security Bulletin Summary
---------------------------------
Product: Siemens SCALANCE products
Publisher: US-CERT
Operating System: Network Appliance
Impact/Access: Execute Arbitrary Code/Commands -- Existing Account
Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2019-10928 CVE-2019-10927
Original Bulletin:
https://www.us-cert.gov/ics/advisories/icsa-19-227-03
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ICS Advisory (ICSA-19-227-03)
Siemens SCALANCE Products
Original release date: August 15, 2019
Legal Notice
All information products included in http://ics-cert.us-cert.gov are
provided"as is" for informational purposes only. The Department of Homeland
Security (DHS) does not provide any warranties of any kind regarding any
information contained within. DHS does not endorse any commercial product or
service, referenced in this product or otherwise. Further dissemination of this
product is governed by the Traffic Light Protocol (TLP) marking in the header.
For more information about TLP, see http://www.us-cert.gov/tlp/ .
1. EXECUTIVE SUMMARY
o CVSS v3 6.6
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Siemens
o Equipment: SCALANCE Products
o Vulnerabilities: Improper Adherence to Coding Standards
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could lead to a denial of
service or could allow an authenticated local userwith physical access to the
device to execute arbitrary commands on the device.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following Siemens SCALANCE products are affected by these vulnerabilities:
o SCALANCE SC-600: v2.0
o SCALANCE XB-200: v4.1 (only affected by CVE-2019-10927)
o SCALANCE XC-200: v4.1 (only affected by CVE-2019-10927)
o SCALANCE XF-200BA: v4.1 (only affected by CVE-2019-10927)
o SCALANCE XP-200: v4.1 (only affected by CVE-2019-10927)
o SCALANCE SR-300WG: v4.1 (only affected by CVE-2019-10927)
3.2 VULNERABILITY OVERVIEW
3.2.1 IMPROPER ADHERENCE TO CODING STANDARDS CWE-710
An authenticated attacker with network access to Port 22/TCP of an affected
device may cause a denial-of-service condition.
This security vulnerability could be exploited by an authenticated attacker
with network access to the affected device. No user interaction is required to
exploit this vulnerability. The vulnerability impacts the availability of the
affected device.
CVE-2019-10927 has been assigned to this vulnerability. A CVSS v3 base score of
6.5 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:N/S:U/C:N/
I:N/A:H ).
3.2.2 IMPROPER ADHERENCE TO CODING STANDARDS CWE-710
An authenticated attacker with access to Port 22/TCP as well as physical access
to an affected device may trigger the device to allow execution of arbitrary
commands.
The security vulnerability could be exploited by an authenticated attacker with
physical access to the affected device. No user interaction is required to
exploit this vulnerability. The vulnerability impacts the confidentiality,
integrity, and availability of the affected device.
CVE-2019-10928 has been assigned to this vulnerability. A CVSS v3 base score of
6.6 has been assigned; the CVSS vector string is ( AV:P/AC:L/PR:L/UI:N/S:U/C:H/
I:H/A:H ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Chemical, Critical Manufacturing, Energy,
Food and Agriculture, and Water and Wastewater Systems
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Germany
3.4 RESEARCHER
Siemens reported these vulnerabilities to CISA.
4. MITIGATIONS
Siemens currently has an update for the following product:
o SCALANCE SC-600: Update to v2.0.1
For the balance of the listed products, Siemens is preparing further updates
and recommends users apply the following specific workarounds and mitigations
to reduce risk until patches are available:
o Restrict access to Port 22/TCP (use the built-in firewall for SCALANCE
SC-600);
o Restrict physical access to the device.
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 configuring the
environment according to Siemens' operational guidelines for Industrial
Security , and following 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 the Siemens ProductCERT: https://www.siemens.com/cert
/advisories
For more information on these vulnerabilities and more detailed mitigation
instructions, please see Siemens security advisory SSA-671286 at the following
location: http://www.siemens.com/cert/advisories
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 these vulnerabilities.
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