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AUSCERT External Security Bulletin Redistribution
ESB-2020.3086
Advisory (icsa-20-252-06) Siemens SIMATIC HMI Products
9 September 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: Siemens SIMATIC HMI Products
Publisher: US-CERT
Operating System: Network Appliance
Impact/Access: Access Confidential Data -- Remote/Unauthenticated
Unauthorised Access -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2020-15787 CVE-2020-15786
Original Bulletin:
https://us-cert.cisa.gov/ics/advisories/icsa-20-252-06
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ICS Advisory (ICSA-20-252-06)
Siemens SIMATIC HMI Products
Original release date: September 08, 2020
Legal Notice
All information products included in https://us-cert.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://www.us-cert.gov/tlp/ .
1. EXECUTIVE SUMMARY
o CVSS v3 6.5
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Siemens
o Equipment: SIMATIC HMI
o Vulnerabilities: Improper Restriction of Excessive Authentication Attempts,
Authentication Bypass by Primary Weakness
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow a remote attacker
to discover user passwords and obtain access to the Sm@rt Server via a
brute-force attack.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of Siemens SIMATIC HMI Products are affected:
o SIMATIC HMI Basic Panels, 2nd Generation (incl. SIPLUS variants): Version
14 and above and versions prior to XX are affected by CVE-2020-15786
o SIMATIC HMI Comfort Panels (incl. SIPLUS variants): All versions are
affected by CVE-2020-15786
o SIMATIC HMI Mobile Panels: All versions are affected by CVE-2020-15786
o SIMATIC HMI United Comfort Panels: All versions
3.2 VULNERABILITY OVERVIEW
3.2.1 IMPROPER RESTRICTION OF EXCESSIVE AUTHENTICATION ATTEMPTS CWE-307
Affected devices insufficiently block excessive authentication attempts. This
could allow a remote attacker to discover user passwords and obtain access to
the Sm@rt Server via a brute-force attack.
CVE-2020-15786 has been assigned to this vulnerability. A CVSS v3 base score of
6.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:N/I:L/A:L ).
3.2.2 AUTHENTICATION BYPASS BY PRIMARY WEAKNESS CWE-305
Affected devices insufficiently validate authentication attempts as the
information given can be truncated to match only a set number of characters
versus the whole provided string. This could allow a remote attacker to
discover user passwords and obtain access to the Sm@rt Server via a brute-force
attack.
CVE-2020-15787 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: Energy
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Germany
3.4 RESEARCHER
Joseph Gardiner from Bristol Cyber Security Group, University of Bristol,
reported these vulnerabilities to Siemens.
4. MITIGATIONS
Siemens is preparing updates and recommends specific countermeasures for
products where updates are not yet available. Siemens has identified the
following specific workarounds and mitigations users can apply to reduce the
risk:
o Apply defense-in-depth strategies outlined here: https://www.siemens.com/
cert/operational-guidelines-industrial-security
As a general security measure, Siemens strongly 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 the recommendations in the product manuals.
For additional information, please refer to Siemens Security Advisory
SSA-542525
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.
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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