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# SSA-507847: Cross-Site Request Forgery Vulnerability in SIMATIC S7-1200 CPU Family
Version 4

Publication Date:        2018-10-09
Last Update:             2020-02-10
Current Version:         1.1
CVSS v3.1 Base Score:    7.5

SUMMARY
=======

The latest firmware update for S7-1200 CPU family version 4 fixes a
Cross-Site Request Forgery vulnerability. Siemens recommends to update
affected devices as soon as possible.


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


* SIMATIC S7-1200 CPU family version 4 (incl. SIPLUS variants) 
  - Affected versions:
       All versions < V4.2.3
  - Remediation:
       Update to V4.2.3
  - Download:
       https://support.industry.siemens.com/cs/us/en/view/109741461


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

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

* Do not visit other websites while being authenticated against the PLC.
  


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
===================

Products of the SIMATIC S7-1200 CPU family have been designed for
discrete and continuous control in industrial environments such as
manufacturing, food and beverages, and chemical industries worldwide.

SIPLUS extreme products are designed for reliable operation under
extreme conditions and are based on SIMATIC, LOGO!, SITOP, SINAMICS,
SIMOTION, SCALANCE or other devices. SIPLUS devices use the same
firmware as the product they are based on.

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-2018-13800

  The web interface could allow a Cross-Site Request Forgery (CSRF) attack
  if an unsuspecting user is tricked into accessing a malicious link.
  
  Successful exploitation requires user interaction by a legitimate user,
  who must be authenticated to the web interface. A successful attack
  could allow an attacker to trigger actions via the web interface that
  the legitimate user is allowed to perform. This could allow the attacker
  to read or modify parts of the device configuration.
  
  At the time of advisory publication no public exploitation of this
  vulnerability was known.

  CVSS v3.1 Base Score: 7.5
  CVSS Vector:          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
  CWE:                  CWE-352: Cross-Site Request Forgery (CSRF)


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

Siemens thanks the following parties for their efforts:

   * Lisa Fournet and Marl Joos from P3 communications GmbH for coordinated disclosure
   * Artem Zinenko from Kaspersky for pointing out that SIPLUS should also be mentioned



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 (2018-10-09): Publication Date
V1.1 (2020-02-10): SIPLUS devices now explicitly mentioned in the list of affected products

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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