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AUSCERT External Security Bulletin Redistribution
ESB-2020.2393.3
Advisory (icsa-20-196-05) Siemens UMC Stack
13 November 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: Siemens UMC Stack
Publisher: ICS-CERT
Operating System: Network Appliance
Impact/Access: Increased Privileges -- Existing Account
Denial of Service -- Remote/Unauthenticated
Reduced Security -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2020-7588 CVE-2020-7587 CVE-2020-7581
Original Bulletin:
https://us-cert.cisa.gov/ics/advisories/icsa-20-196-05
Revision History: November 13 2020: Vendor updated advisory
August 12 2020: SIMATIC PCS neo: Update to v3.0 SP1
July 15 2020: Initial Release
- --------------------------BEGIN INCLUDED TEXT--------------------
ICS Advisory (ICSA-20-196-05)
Siemens UMC Stack (Update C)
Original release date: November 10, 2020
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 6.7
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Siemens
o Equipment: UMC Stack
o Vulnerabilities: Unquoted Search Path or Element, Uncontrolled Resource
Consumption, Improper Input Validation
2. UPDATE INFORMATION
This updated advisory is a follow-up to the advisory update titled
ICSA-20-196-05 Siemens UMC Stack (Update B) that was published September 8,
2020, to the ICS webpage on us-cert.cisa.gov.
3. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to
cause a partial denial-of-service condition on the UMC component of the
affected devices under certain circumstances. This could also allow an attacker
to locally escalate privileges from a user with administrative privileges to
execute code with SYSTEM level privileges.
4. TECHNICAL DETAILS
4.1 AFFECTED PRODUCTS
Siemens reports that some of the vulnerabilities affect the following UMC
components. For a complete list of which specific vulnerabilities affect each
of these products,please see Siemens security advisory SSA-841348 :
o Opcenter Execution Discrete: All versions prior to v3.2
o Opcenter Execution Foundation: All versions prior to v3.2
o Opcenter Execution Process: All versions prior to v3.2
o Opcenter Intelligence: All versions
o Opcenter Quality: All versions prior to v11.3
o Opcenter RD&L: v8.0
o SIMATIC IT LMS: All versions
o SIMATIC IT Production Suite: All versions
o SIMATIC Notifier Server for Windows: All versions
o SIMATIC PCS neo: All versions prior to v3.0 SP1
o SIMATIC STEP 7 (TIA Portal) v15: All versions prior to v15.1 update 5
o SIMATIC STEP 7 (TIA Portal) v16: All versions prior to v16 Update 2
- --------- Begin Update C Part 1 of 2 ---------
o SIMOCODE ES: All versions prior to v16 Update 1
- --------- End Update C Part 1 of 2 ---------
o Soft Starter ES: All versions
4.2 VULNERABILITY OVERVIEW
4.2.1 UNQUOTED SEARCH PATH OR ELEMENT CWE-428
A component within the affected application calls a helper binary with SYSTEM
privileges during startup while the call path is not quoted.
CVE-2020-7581 has been assigned to this vulnerability. A CVSS v3 base score of
6.7 has been calculated; the CVSS vector string is (A V:L/AC:L/PR:H/UI:N/S:U/
C:H/I:H/A:H ).
4.2.2 UNCONTROLLED RESOURCE CONSUMPTION CWE-400
Sending multiple specially crafted packets to the affected service could cause
a partially remote denial of service, which would cause the service to restart
itself.
CVE-2020-7587 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:L/I:N/A:L ).
4.2.3 IMPROPER INPUT VALIDATION CWE-20
Sending a specially crafted packet to the affected service could cause a
partially remote denial of service, which would cause the service to restart
itself.
CVE-2020-7588 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:N/A:L ).
4.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Germany
4.4 RESEARCHER
Victor Fidalgo of INCIBE and Reid Wightman of Dragos reported these
vulnerabilities to Siemens.
5. MITIGATIONS
Siemens recommends users upgrade affected products if upgrade are available for
those products:
o Opcenter Execution Discrete, Foundation, and Process: Update to v3.2 or
later
o Opcenter Quality: Update to v11.3 or later
o Opcenter RD&L: Update to v8.1 or later
o SIMATIC PCS neo: Update to v3.0 SP1. To obtain this update contact local
support.
o SIMATIC STEP 7 (TIA Portal) v15: Update to v15.1 update 5 or later
o SIMATIC STEP 7 (TIA Portal) v16: Update to v16 Update 2 or later
- --------- Begin Update C Part 2 of 2 ---------
o SIMOCODE ES: Update to v16 Update 1 or later
- --------- End Update C Part 2 of 2 ---------
For products that do not have an update, Siemens has identified the following
specific workarounds and mitigations customers can apply to reduce the risk:
o Run the software on systems within trusted networks
o For CVE-2020-7581, ensure there is no executable at the following
locations:
C:\Program.exe
C:\Program Files\Common.exe
C:\Program Files\Common Files\Siemens\Automation\Simatic.exe
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.
Additional information on Industrial Security by Siemens can be found at:
https://www.siemens.com/industrialsecurity
For more information on these vulnerabilities and associated software updates,
please see Siemens security advisory SSA-841348
CISA recommends users take the following measures to protect themselves from
social engineering attacks:
o Do not click web links or open unsolicited attachments in email messages.
o Refer to Recognizing and Avoiding Email Scams for more information on
avoiding email scams.
o Refer to Avoiding Social Engineering and Phishing Attacks for more
information on social engineering attacks.
CISA reminds organizations to perform proper impact analysis and risk
assessment prior to deploying defensive measures.
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 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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