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# SSA-641963: Remote Code Execution Vulnerability in Multiple SIMATIC Software
Products

Publication Date:        2021-07-13
Last Update:             2021-07-13
Current Version:         1.0
CVSS v3.1 Base Score:    7.8

SUMMARY
=======

Multiple SIMATIC Software products are affected by a vulnerability that
could allow an attacker to manipulate project files and remotely execute
code.

Siemens has released updates for several affected products and
recommends to update to the latest versions. Siemens recommends specific
countermeasures for products where updates are not, or not yet
available.


AFFECTED PRODUCTS AND SOLUTION
==============================


* SIMATIC PCS 7 V8.2 and earlier 
  - Affected versions:
       All versions
  - Remediation:
       See recommendations from section "Workarounds and Mitigations"

* SIMATIC PCS 7 V9.0 
  - Affected versions:
       All versions < V9.0 SP3
  - Remediation:
       Update to V9.0 SP3 or later version
  - Download:
       To obtain SIMATIC PCS 7 V9.0 SP3 contact your local customer support.

* SIMATIC PDM 
  - Affected versions:
       All versions < V9.2
  - Remediation:
       Update to V9.2 or later version
  - Download:
       https://support.industry.siemens.com/cs/ww/en/view/109794361/

* SIMATIC STEP 7 V5.X 
  - Affected versions:
       All versions < V5.6 SP2 HF3
  - Remediation:
       Update to V5.6 SP2 HF3 or later version
  - Download:
       https://support.industry.siemens.com/cs/de/en/view/109779992/

* SINAMICS STARTER (containing STEP 7 OEM version) 
  - Affected versions:
       All versions < V5.4 HF2
  - Remediation:
       Update to V5.4 HF2 or later version
  - Download:
       https://support.industry.siemens.com/cs/us/en/view/109782792/


WORKAROUNDS AND MITIGATIONS
===========================

Siemens has identified the following specific workarounds and mitigations that
customers can apply to reduce the risk:

* Restrict access to project files on the engineering station to trusted
users

* Only use project files from trusted sources



GENERAL SECURITY RECOMMENDATIONS
================================

As a general security measure, Siemens strongly recommends to protect
network access to devices with appropriate mechanisms. In order to
operate the devices in a protected IT environment, Siemens recommends to
configure the environment according to Siemens' operational guidelines
for Industrial Security (Download:
https://www.siemens.com/cert/operational-guidelines-industrial-security),
and to follow the recommendations in the product manuals.

Additional information on Industrial Security by Siemens can be found
at: https://www.siemens.com/industrialsecurity

PRODUCT DESCRIPTION
===================

SIMATIC PCS 7 is a distributed control system (DCS) integrating SIMATIC
WinCC, SIMATIC Batch, SIMATIC Route Control, OpenPCS7 and other
components.

SIMATIC PDM (Process Device Manager) is an universal,
manufacturer-independent tool for configuration, parameter assignment,
commissioning, diagnostics and maintenance of intelligent process
devices (actors, sensors) and automation components (remote I/Os,
multiplexer, process control units, compact controller).

SIMATIC STEP 7 V5.X is the classic engineering software to configure and
program SIMATIC S7-300/S7-400/C7/WinAC controllers.

STARTER is the drive engineering tool for parameterizing and
commissioning.

VULNERABILITY CLASSIFICATION
============================

The vulnerability classification has been performed by using the CVSS scoring
system in version 3.1 (CVSS v3.1) (https://www.first.org/cvss/). The CVSS
environmental score is specific to the customer's environment and will impact
the overall CVSS score. The environmental score should therefore be
individually defined by the customer to accomplish final scoring.

An additional classification has been performed using the CWE classification, a
community-developed list of common software security weaknesses. This serves as
a common language and as a baseline for weakness identification, mitigation,
and prevention efforts. A detailed list of CWE classes can be found at:
https://cwe.mitre.org/.



* Vulnerability CVE-2021-31893

  The affected software contains a buffer overflow vulnerability while
  handling certain files that could allow a local attacker to trigger a
  denial-of-service condition or potentially lead to remote code
  execution.

  CVSS v3.1 Base Score: 7.8
  CVSS Vector:          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
  CWE:                  CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')


ACKNOWLEDGMENTS
===============

Siemens thanks the following parties for their efforts:

   * Uri Katz from Claroty for coordinated disclosure



ADDITIONAL INFORMATION
======================

For further inquiries on security vulnerabilities in Siemens products and
solutions, please contact the Siemens ProductCERT:

https://www.siemens.com/cert/advisories


HISTORY DATA
============

V1.0 (2021-07-13): Publication Date

TERMS OF USE
============

Siemens Security Advisories are subject to the terms and conditions contained
in Siemens' underlying license terms or other applicable agreements previously
agreed to with Siemens (hereinafter "License Terms"). To the extent applicable
to information, software or documentation made available in or through a
Siemens Security Advisory, the Terms of Use of Siemens' Global Website
(https://www.siemens.com/terms_of_use, hereinafter "Terms of Use"), in
particular Sections 8-10 of the Terms of Use, shall apply additionally. In case
of conflicts, the License Terms shall prevail over the Terms of Use.
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