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AUSCERT External Security Bulletin Redistribution
ESB-2021.1900
Advisory (icsa-21-152-01) Siemens SIMATIC S7-1200 and S7-1500 CPU Families
2 June 2021
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AusCERT Security Bulletin Summary
---------------------------------
Product: Siemens SIMATIC S7-1200 and S7-1500 CPU Families
Publisher: ICS-CERT
Operating System: Network Appliance
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Access Confidential Data -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2020-15782
Original Bulletin:
https://us-cert.cisa.gov/ics/advisories/icsa-21-152-01
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ICS Advisory (ICSA-21-152-01)
Siemens SIMATIC S7-1200 and S7-1500 CPU Families
Original release date: June 01, 2021
Legal Notice
All information products included in https://us-cert.cisa.gov/ics 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 https://us-cert.cisa.gov/tlp/ .
1. EXECUTIVE SUMMARY
o CVSS v3 8.1
o ATTENTION: Exploitable remotely
o Vendor: Siemens
o Equipment: SIMATIC S7-1200 and S7-1500 CPU Families
o Vulnerability: Improper Restriction of Operations within the Bounds of a
Memory Buffer\
2. RISK EVALUATION
Successful exploitation of this vulnerability could allow an attacker to write
arbitrary data and code to protected memory areas or read sensitive data to
launch further attacks.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Siemens reports this vulnerability affects the following SIMATIC S7-1200 and
S7-1500 CPU products:
o SIMATIC Drive Controller family: All versions prior to v2.9.2
o SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants):
All versions
o SIMATIC ET 200SP Open Controller CPU 1515SP PC (incl. SIPLUS variants): All
versions
o SIMATIC S7-1200 CPU family (incl. SIPLUS variants): All versions prior to
v4.5.0
o SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants):
All versions prior to v2.9.2
o SIMATIC S7-1500 Software Controller: All versions
o SIMATIC S7-PLCSIM Advanced: All versions prior to v4.0
3.2 VULNERABILITY OVERVIEW
3.2.1 IMPROPER RESTRICTION OF OPERATIONS WITHIN THE BOUNDS OF A MEMORY BUFFER
CWE-119
Affected devices are vulnerable to a memory protection bypass through a
specific operation. A remote, unauthenticated attacker with network access to
Port 102/TCP could write arbitrary data and code to protected memory areas or
read sensitive data to launch further attacks.
CVE-2020-15782 has been assigned to this vulnerability. A CVSS v3 base score of
8.1 has been calculated; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:N/S:U/
C:H/I:H/A:H ).
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
Tal Keren from Claroty reported this vulnerability to Siemens.
4. MITIGATIONS
Siemens has released updates for several affected products and recommends
updating to the latest versions. Siemens is preparing further updates and
recommends specific countermeasures for products where updates are not, or not
yet available.
o SIMATIC Drive Controller family: Update to v2.9.2 or later version
o SIMATIC S7-1200 CPU family (incl. SIPLUS variants): Update to v4.5.0 or
later version
o SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants):
Update to v2.9.2 or later version
o SIMATIC S7-PLCSIM Advanced: Update to v4.0 or later version
Siemens has identified the following specific workarounds and mitigations users
can apply to reduce the risk:
o Apply password protection for S7 communication.
o Disallow client connections via the ENDIS_PW instruction of the S7-1200 or
S7-1500 CPU (This blocks remote client connections, even when the client
can provide the correct password).
o Use the display to configure additional access protection of the S7-1500
CPU (This blocks remote client connections, even when the client can
provide the correct password).
o Apply "defense in depth" as outlined on pages 12ff of the operational
guidelines for industrial security, especially:
Plant security: Ensure physical prevention of access to critical
components.
Network security: Ensure PLC systems are not connected to untrusted
networks.
System integrity: Configure, maintain, and protect devices by applying
applicable compensating controls and using built-in security
capabilities.
o Update the entire solution to TIA Portal v17 and use TLS communication
using individual certificates between PLC, HMIs, and PG/PC
For more information about this vulnerability and the associated mitigations,
please see SSA-434534
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 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 us-cert.cisa.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.cisa.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. This
vulnerability has a high attack complexity.
For any questions related to this report, please contact the CISA at:
Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870
CISA continuously strives to improve its products and services. You can help by
choosing one of the links below to provide feedback about this product.
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