Siemens has identified the following specific mitigations that customers can apply to reduce the risk:
CVE-2020-24588
Disable A-MSDU, if possible
As these vulnerabilities can only be exploited within Wi-Fi range, when possible reduce Wi-Fi transmission power or make sure to have the devices in private areas with physical access controls
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 W products are wireless communication devices used to connect industrial components, like Programmable Logic Controllers (PLCs) or Human Machine Interfaces (HMIs), according to the IEEE 802.11 standard (802.11ac, 802.11a/b/g/h, and/or 802.11n).
SCALANCE W-1700 products are wireless communication devices based on IEEE 802.11ac standard. They are used to connect all to sorts of WLAN devices (Access Points or Clients, depending on the operating mode) with a strong focus on industrial components, like Programmable Logic Controllers (PLCs) or Human Machine Interfaces (HMIs) and others.
SCALANCE W1750D is an Access Point that supports IEEE 802.11ac standards for high-performance WLAN, and is equipped with two dual-band radios, which can provide access and monitor the network simultaneously.
This chapter describes all vulnerabilities (CVE-IDs) addressed in this security advisory.
Wherever applicable, it also documents the product-specific impact of the individual vulnerabilities.
Vulnerability CVE-2020-24588
The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent Privacy (WEP) doesn't require that the A-MSDU flag in the plaintext QoS header field is authenticated. Against devices that support receiving non-SSP A-MSDU frames (which is mandatory as part of 802.11n), an adversary can abuse this to inject arbitrary network packets.
CVSS v3.1 Base Score
3.5
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
CWE
CWE-306: Missing Authentication for Critical Function
Vulnerability CVE-2020-26139
An issue was discovered in the kernel in NetBSD 7.1. An Access Point (AP) forwards EAPOL frames to other clients even though the sender has not yet successfully authenticated to the AP. This might be abused in projected Wi-Fi networks to launch denial-of-service attacks against connected clients and makes it easier to exploit other vulnerabilities in connected clients.
CVSS v3.1 Base Score
5.3
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
CWE-287: Improper Authentication
Vulnerability CVE-2020-26140
An issue was discovered in the ALFA Windows 10 driver 6.1316.1209 for AWUS036H. The WEP, WPA, WPA2, and WPA3 implementations accept plaintext frames in a protected Wi-Fi network. An adversary can abuse this to inject arbitrary data frames independent of the network configuration.
CVSS v3.1 Base Score
6.5
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE
CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Vulnerability CVE-2020-26141
An issue was discovered in the ALFA Windows 10 driver 6.1316.1209 for AWUS036H. The Wi-Fi implementation does not verify the Message Integrity Check (authenticity) of fragmented TKIP frames. An adversary can abuse this to inject and possibly decrypt packets in WPA or WPA2 networks that support the TKIP data-confidentiality protocol.
CVSS v3.1 Base Score
6.5
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE
CWE-354: Improper Validation of Integrity Check Value
Vulnerability CVE-2020-26143
An issue was discovered in the ALFA Windows 10 driver 1030.36.604 for AWUS036ACH. The WEP, WPA, WPA2, and WPA3 implementations accept fragmented plaintext frames in a protected Wi-Fi network. An adversary can abuse this to inject arbitrary data frames independent of the network configuration.
CVSS v3.1 Base Score
6.5
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE
CWE-20: Improper Input Validation
Vulnerability CVE-2020-26144
An issue was discovered on Samsung Galaxy S3 i9305 4.4.4 devices. The WEP, WPA, WPA2, and WPA3 implementations accept plaintext A-MSDU frames as long as the first 8 bytes correspond to a valid RFC1042 (i.e., LLC/SNAP) header for EAPOL. An adversary can abuse this to inject arbitrary network packets independent of the network configuration.
CVSS v3.1 Base Score
6.5
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE
CWE-20: Improper Input Validation
Vulnerability CVE-2020-26145
An issue was discovered on Samsung Galaxy S3 i9305 4.4.4 devices. The WEP, WPA, WPA2, and WPA3 implementations accept second (or subsequent) broadcast fragments even when sent in plaintext and process them as full unfragmented frames. An adversary can abuse this to inject arbitrary network packets independent of the network configuration.
CVSS v3.1 Base Score
6.5
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE
CWE-20: Improper Input Validation
Vulnerability CVE-2020-26146
An issue was discovered on Samsung Galaxy S3 i9305 4.4.4 devices. The WPA, WPA2, and WPA3 implementations reassemble fragments with non-consecutive packet numbers. An adversary can abuse this to exfiltrate selected fragments. This vulnerability is exploitable when another device sends fragmented frames and the WEP, CCMP, or GCMP data-confidentiality protocol is used. Note that WEP is vulnerable to this attack by design.
CVSS v3.1 Base Score
5.3
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE
CWE-20: Improper Input Validation
Vulnerability CVE-2020-26147
An issue was discovered in the Linux kernel 5.8.9. The WEP, WPA, WPA2, and WPA3 implementations reassemble fragments even though some of them were sent in plaintext. This vulnerability can be abused to inject packets and/or exfiltrate selected fragments when another device sends fragmented frames and the WEP, CCMP, or GCMP data-confidentiality protocol is used.
CVSS v3.1 Base Score
5.4
CVSS v3.1 Vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N
CWE
CWE-20: Improper Input Validation
ADDITIONAL INFORMATION
For more details regarding the FragAttacks vulnerabilities refer to:
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
V1.1 (2021-10-12):
Added fix for SCALANCE W1750D
V1.2 (2022-02-08):
Added fix for SCALANCE W-700 IEEE 802.11ax family; updated name and split into individual products the SCALANCE W-700 and SCALANCE W-1700 families; clarified that no fix is planned for SCALANCE W-700 IEEE 802.11n and SCALANCE W-1700 IEEE 802.11ac families
V1.3 (2022-04-12):
Added fix for SCALANCE W-1700 IEEE 802.11ac family
V1.4 (2025-04-08):
Clarified fix version information for SCALANCE W-700 IEEE 802.11ax family