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# SSA-139628: Vulnerabilities in Web Server for Scalance X Products

Publication Date:        2021-01-12
Last Update:             2021-09-14
Current Version:         1.2
CVSS v3.1 Base Score:    9.8

SUMMARY
=======

Several SCALANCE X switches contain vulnerabilities in the web server of
the affected devices.

An unauthenticated attacker could reboot, cause denial-of-service
conditions and potentially impact the system by other means through heap
and buffer overflow vulnerabilities.

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


* SCALANCE X-200 switch family (incl. SIPLUS NET variants) 
  - Affected versions:
       All versions < V5.2.5
  - Remediation:
       Update to V5.2.5 or later version
  - Download:
       https://support.industry.siemens.com/cs/ww/en/view/109801131/

* SCALANCE X-200IRT switch family (incl. SIPLUS NET variants) 
  - Affected versions:
       All versions < V5.5.0
  - Remediation:
       Update to V5.5.0 or later version
  - Download:
       https://support.industry.siemens.com/cs/ww/en/view/109792534/

* SCALANCE X-300 switch family (incl. X408 and SIPLUS NET variants) 
  - Affected versions:
       All versions < V4.1.0
  - Affected by vulnerabilities:
    - CVE-2020-15800
  - Remediation:
       Update to V4.1.0 or later version
  - Download:
       https://support.industry.siemens.com/cs/ww/en/view/109773547/


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

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

* Limit network traffic of web servers of Scalance X switches to trusted
connections by firewall rules (port 443/tcp).



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

SCALANCE X switches are used to connect industrial components like
Programmable Logic Controllers (PLCs) or Human Machine Interfaces
(HMIs).

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-2020-15799

  The vulnerability could allow an unauthenticated attacker to reboot the
  device over the network by using special urls from integrated web server
  of the affected products.

  CVSS v3.1 Base Score: 7.5
  CVSS Vector:          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C
  CWE:                  CWE-306: Missing Authentication for Critical Function

* Vulnerability CVE-2020-15800

  The webserver of the affected devices contains a vulnerability that may
  lead to a heap overflow condition. An attacker could cause this
  condition on the webserver by sending specially crafted requests. This
  could stop the webserver temporarily.

  CVSS v3.1 Base Score: 9.8
  CVSS Vector:          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:C
  CWE:                  CWE-122: Heap-based Buffer Overflow

* Vulnerability CVE-2020-25226

  The web server of the affected devices contains a vulnerability that may
  lead to a buffer overflow condition. An attacker could cause this
  condition on the webserver by sending a specially crafted request. The
  webserver could stop and not recover anymore.

  CVSS v3.1 Base Score: 9.8
  CVSS Vector:          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:C
  CWE:                  CWE-122: Heap-based Buffer Overflow




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 (2021-01-12): Publication Date
V1.1 (2021-02-09): Added update information for SCALANCE X-200IRT switch family
V1.2 (2021-09-14): Added solution for SCALANCE X-200 switch family

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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