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# SSA-178380: Denial-of-Service Vulnerability in SINUMERIK Controllers

Publication Date:        2021-10-12
Last Update:             2021-10-12
Current Version:         1.0
CVSS v3.1 Base Score:    7.5

SUMMARY
=======

A Denial-of-Service vulnerability found in SINUMERIK Controllers could
allow an unauthenticated attacker with network access to the affected
devices to cause system failure with total loss of availability.

Siemens has released an update for the SINUMERIK 828D and recommends to
update to the latest version. Siemens recommends specific
countermeasures for products where updates are not, or not yet
available.


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


* SINUMERIK 808D 
  - Affected versions:
       All versions
  - Remediation:
       See recommendations from section "Workarounds and Mitigations"

* SINUMERIK 828D 
  - Affected versions:
       All versions < V4.95
  - Remediation:
       Update to V4.95 or later version
  - Download:
       The update can be obtained from your Siemens representative or via
       Siemens customer service.


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

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

* Restrict access to port 102/tcp to trusted systems e.g. with an external
firewall

* Apply general workarounds.



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

SINUMERIK CNC offers automation solutions for the shop floor, job shops
and large serial production environments.

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-2021-37199

  Affected devices don't process correctly certain special crafted packets
  sent to port 102/tcp, which could allow an attacker to cause a
  denial-of-service in the device.

  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-122: Heap-based Buffer Overflow


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

Siemens thanks the following parties for their efforts:

   * Industrial Control Security Laboratory of Qi An Xin Group Inc. for reporting the vulnerability and coordination efforts



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 (2021-10-12): 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.
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