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AUSCERT External Security Bulletin Redistribution
ESB-2019.4621
Advisory (icsa-19-344-06) Siemens SIMATIC S7-1200 and S7-1500 CPU Families
11 December 2019
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AusCERT Security Bulletin Summary
---------------------------------
Product: Siemens SIMATIC S7-1200 & S7-1500 CPU
Publisher: ICS-CERT
Operating System: Network Appliance
Impact/Access: Modify Arbitrary Files -- Remote/Unauthenticated
Provide Misleading Information -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2019-10943 CVE-2019-10929
Original Bulletin:
https://www.us-cert.gov/ics/advisories/icsa-19-344-06
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ICS Advisory (ICSA-19-344-06)
Siemens SIMATIC S7-1200 and S7-1500 CPU Families
Original release date: December 10, 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 5.3
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Siemens
o Equipment: SIMATIC S7-1200 and S7-1500 CPU families
o Vulnerabilities: Use of a Broken or Risky Cryptographic Algorithm, Missing
Support for Integrity Check
2. RISK EVALUATION
Successful exploitation of these vulnerabilities may allow an attacker to
modify network traffic or impact the perceived integrity of the user program
stored on the CPU.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Siemens reports that these vulnerabilities affect the following SIMATIC
products:
o SIMATIC ET200SP (incl. SIPLUS variants) Open Controller CPU 1515SP PC: All
versions
o SIMATIC ET200SP (incl. SIPLUS variants) Open Controller CPU 1515SP PC2: All
versions
o SIMATIC S7 PLCSIM Advanced: All versions up to and including v3.0
o SIMATIC S7-1200 CPU family (incl. SIPLUS variants): All versions up to and
including v4.4
o SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants),
excluding CPU 1518-4 PN/DP and CPU 1518 MFP (and related SIPLUS variant):
All versions up to and including v2.8.1
o SIMATIC S7-1500 Software Controller: All versions
3.2 VULNERABILITY OVERVIEW
3.2.1 USE OF A BROKEN OR RISKY CRYPTOGRAPHIC ALGORITHM CWE-327
An attacker in a man-in-the-middle position could modify network traffic
exchanged on Port 102/TCP, due to certain properties in the calculation used
for integrity protection.
CVE-2019-10929 has been assigned to this vulnerability. A CVSS v3 base score of
3.7 has been calculated; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:N/S:U/
C:N/I:L/A:N ).
3.2.2 MISSING SUPPORT FOR INTEGRITY CHECK CWE-353
An attacker with network access to Port 102/TCP could modify the user program
on the PLC in a way that the running code is different from the source code
stored on the device.
CVE-2019-10943 has been assigned to this vulnerability. A CVSS v3 base score of
5.3 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:N/I:L/A:N ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Chemical, Critical Manufacturing, Energy,
Food and Agriculture, Water and Wastewater Systems
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Germany
3.4 RESEARCHER
Eli Biham, Sara Bitan, Aviad Carmel, and Alon Dankner from Faculty of Computer
Science, Technion Haifa; Uriel Malin and Avishai Wool from School of Electrical
Engineering, Tel-Aviv University; and Artem Zinenko from Kaspersky reported
these vulnerabilities to Siemens.
4. MITIGATIONS
Siemens has released updates for the following products and recommends users
update to the new version.
o SIMATIC S7 PLCSIM Advanced: Update to v3.0
o SIMATIC S7-1200 CPU family: Update to v4.4
o SIMATIC S7-1500 CPU family: Update to v2.8.1
Siemens is preparing further updates and recommends specific countermeasures
until patches are available:
o All affected devices contain a feature called "Access Protection" that
prohibits unauthorized modifications of user code. Siemens recommends using
access protection to protect affected devices from unauthorized
modifications.
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 .
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
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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