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# SSA-448291: Denial-of-Service Vulnerability in ARP Protocol of RWG Universal
Controllers

Publication Date:        2021-07-13
Last Update:             2021-07-13
Current Version:         1.0
CVSS v3.1 Base Score:    6.5

SUMMARY
=======

A Denial-of-Service vulnerability was found affecting the ARP protocol
on RWG Universal Controller devices.

Siemens has released updates for the affected products and recommends to
update to the latest versions.


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


* RWG1.M8 
  - Affected versions:
       All versions < V1.16.16
  - Remediation:
       Login to the RWG Controller Graphical programming platform, generate a
       new project file and download the new project file to the device
  - Download:
       https://www.ubc.siemens.com.cn/

* RWG1.M12 
  - Affected versions:
       All versions < V1.16.16
  - Remediation:
       Login to the RWG Controller Graphical programming platform, generate a
       new project file and download the new project file to the device
  - Download:
       https://www.ubc.siemens.com.cn/

* RWG1.M12D 
  - Affected versions:
       All versions < V1.16.16
  - Remediation:
       Login to the RWG Controller Graphical programming platform, generate a
       new project file and download the new project file to the device
  - Download:
       https://www.ubc.siemens.com.cn/


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

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

* Ensure that only trusted systems are connected to the same Layer 2
domain as the affected devices

* Restrict access to systems in the same Layer 2 domain as the affected
devices to trusted persons only



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

As a general security measure Siemens strongly recommends to protect
network access to affected products with appropriate mechanisms. It is
advised to follow recommended security practices in order to run the
devices in a protected IT environment.

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

RWG Universal Controllers are used to monitor and control FAU, AHU, heat
exchange units, fans, pumps, lighting and other electromechanical
equipments.

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-2021-25671

  Sending specially crafted ARP packets to an affected device could cause
  a partial denial-of-service, preventing the device to operate normally.
  A restart is needed to restore normal operations.

  CVSS v3.1 Base Score: 6.5
  CVSS Vector:          CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C
  CWE:                  CWE-770: Allocation of Resources Without Limits or Throttling




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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