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             AUSCERT External Security Bulletin Redistribution

                               ESB-2020.2393
                Advisory (icsa-20-196-05) Siemens UMC Stack
                               15 July 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

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ICS Advisory (ICSA-20-196-05)

Siemens UMC Stack

Original release date: July 14, 2020

Legal Notice

All information products included in https://us-cert.gov/ics are provided"as
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does not provide any warranties of any kind regarding any information contained
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this product or otherwise. Further dissemination of this product is governed by
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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. 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.

3. TECHNICAL DETAILS

3.1 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 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
  o SIMATIC STEP 7 (TIA Portal) v15: All versions
  o SIMATIC STEP 7 (TIA Portal) v16: All versions prior to V16 Update 2
  o SIMOCODE ES: All versions
  o Soft Starter ES: All versions

3.2 VULNERABILITY OVERVIEW

3.2.1 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 ).

3.2.2 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 ).

3.2.3 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 ).

3.3 BACKGROUND

  o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
  o COUNTRIES/AREAS DEPLOYED: Worldwide
  o COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Victor Fidalgo of INCIBE and Reid Wightman of Dragos reported these
vulnerabilities to Siemens.

4. 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 STEP 7 (TIA Portal) v16: Update to v16 Update 2 or later

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.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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