SSA-686152

Siemens Security Advisory by Siemens ProductCERT

SSA-686152: Denial-of-Service Vulnerability in ARP Protocol of SCALANCE W780 and W740

Publication Date:	2021-02-09
Last Update:	2021-02-09
Current Version:	V1.0
CVSS v3.1 Base Score:	4.3

SUMMARY

A Denial-of-Service vulnerability was found affecting the ARP protocol on older firmware versions of the SCALANCE W780 and W740 (IEEE 802.11n) devices.

Siemens recommends to update to the latest version.

AFFECTED PRODUCTS AND SOLUTION

Affected Product and Versions	Remediation
SCALANCE W780 and W740 (IEEE 802.11n) family: All versions < V6.3	Update to V6.3 or later version https://support.industry.siemens.com/cs/ww/en/view/109781235/

WORKAROUNDS AND MITIGATIONS

Siemens has not identified any specific mitigations or workarounds. Please follow 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

SCALANCE W700 products are wireless communication devices used to connect industrial components like Programmable Logic Controllers (PLCs) or Human Machine Interfaces (HMIs).

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-2021-25666

Sending specially crafted packets through the ARP protocol to an affected device could cause a partial denial-of-service, preventing the device to operate normally for a short period of time.

CVSS v3.1 Base Score	4.3
CVSS Vector	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/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 (2021-02-09): Publication Date

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://new.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.

SSA-686152