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# SSA-350757: Improper Access Control Vulnerability in TIA Portal Affecting S7-1200
and S7-1500 CPUs Web Server (Incl. Related ET200 CPUs and SIPLUS
variants)

Publication Date:        2022-04-12
Last Update:             2022-04-12
Current Version:         1.0
CVSS v3.1 Base Score:    6.4

SUMMARY
=======

An attacker could achieve privilege escalation on the web server of
certain devices configured by SIMATIC STEP 7 (TIA Portal) due to
incorrect handling of the webserver's user management configuration
during downloading. This only affects the S7-1200 and S7-1500 CPUs'
(incl. related ET200 CPUs and SIPLUS variants) web server, when
activated.

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 STEP 7 (TIA Portal) V15
  - Affected versions:
       All versions
  - Remediation:
       Currently no fix is planned
       See recommendations from section "Workarounds and Mitigations"

* SIMATIC STEP 7 (TIA Portal) V16
  - Affected versions:
       All versions < V16 Update 5
  - Remediation:
       Update to V16 Update 5 or later version
       See further recommendations from section "Workarounds and Mitigations"
  - Download:
       https://support.industry.siemens.com/cs/gb/en/view/109775861/

* SIMATIC STEP 7 (TIA Portal) V17
  - Affected versions:
       All versions < V17 Update 2
  - Remediation:
       Update to V17 Update 2 or later version
       See further recommendations from section "Workarounds and Mitigations"
  - Download:
       https://support.industry.siemens.com/cs/gb/en/view/109784441/


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

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

* Whenever changes of the web server's user configuration are performed
with one of the affected versions for S7-1200 or S7-1500 CPUs
(incl. related ET200 CPUs and SIPLUS variants), validate web server
permissions for unauthenticated users by directly accessing the web
server in an unauthenticated manner. In case unauthenticated access is
unintentionally possible, the web server's user configuration needs to
be removed and reconfigured again using a TIA-Portal V16 Update 5 or V17
Update 2 or later

* In case a new TIA-Portal version is not available, updating the web
server's user configuration is not effective in this situation. Instead

- -   the PLC must be deleted and reconfigured with a new project.
    WARNING: The PLC-program should be copied before deleting the PLC.
    Or

- - the original project (one that was not uploaded by a PLC) should be
used to update the web server's user management and to download the
changed configuration


Product specific remediations or mitigations can be found in the section
"Affected Products and Solution".

Please follow the "General Security Recommendations".


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 STEP 7 (TIA Portal) is an engineering software to configure and
program SIMATIC controllers.

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-2021-42029

  An attacker could achieve privilege escalation on the web server of
  certain devices due to improper access control vulnerability in the
  engineering system software. The attacker needs to have direct access to
  the impacted web server.

  CVSS v3.1 Base Score: 6.4
  CVSS Vector:          CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:C/C:H/I:L/A:L/E:P/RL:O/RC:C
  CWE:                  CWE-284: Improper Access Control




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 (2022-04-12): 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.

Copyright: Siemens 2022
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