6.5 Medium
CVSS3
Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7 High
AI Score
Confidence
High
3.3 Low
CVSS2
Access Vector
ADJACENT_NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:A/AC:L/Au:N/C:N/I:P/A:N
0.002 Low
EPSS
Percentile
64.3%
Successful exploitation of these vulnerabilities could allow an attacker within Wi-Fi range to forge encrypted frames, which could result in sensitive data disclosure and traffic manipulation.
The following Siemens products are affected:
The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired Equivalent Privacy (WEP) doesn’t require the A-MSDU flag in the plaintext QoS header field to be 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.
CVE-2020-24588 has been assigned to this vulnerability. A CVSS v3 base score of 3.5 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N).
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.
CVE-2020-26139 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).
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.
CVE-2020-26140 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).
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 decrypt packets in WPA or WPA2 networks that support the TKIP data-confidentiality protocol.
CVE-2020-26141 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).
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.
CVE-2020-26143 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).
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 eight 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.
CVE-2020-26144 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).
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.
CVE-2020-26145 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).
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 WEP is vulnerable to this attack by design.
CVE-2020-26146 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N).
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.
CVE-2020-26147 has been assigned to this vulnerability. A CVSS v3 base score of 5.4 has been assigned; the CVSS vector string is (AV:A/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N).
Siemens reported these vulnerabilities to CISA.
Siemens recommends updating their software to the latest version where available:
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
For more details regarding the FragAttacks vulnerabilities refer to:
As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends users configure the environment according to the Siemens operational guidelines for industrial security and follow the recommendations in the product manuals.
For additional information, please refer to Siemens Security Advisory SSA-913875
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.
No known public exploits specifically target these vulnerabilities.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-24588
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26139
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26140
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26141
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26143
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26144
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26145
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26146
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-26147
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/pdf/ssa-913875.pdf
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/287.html
cwe.mitre.org/data/definitions/306.html
cwe.mitre.org/data/definitions/354.html
cwe.mitre.org/data/definitions/74.html
papers.mathyvanhoef.com/usenix2021.pdf
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/de/en/view/109802805
support.industry.siemens.com/cs/de/en/view/109805887
support.industry.siemens.com/cs/de/en/view/109805887
support.industry.siemens.com/cs/de/en/view/109805887
support.industry.siemens.com/cs/de/en/view/109805887
support.industry.siemens.com/cs/ww/en/view/109808629
support.industry.siemens.com/cs/ww/en/view/109808629
support.industry.siemens.com/cs/ww/en/view/109808629
support.industry.siemens.com/cs/ww/en/view/109808629
support.industry.siemens.com/cs/ww/en/view/109808629
twitter.com/CISAgov
twitter.com/intent/tweet?text=Siemens%20SCALANCE%20FragAttacks+https://www.cisa.gov/news-events/ics-advisories/icsa-22-104-04
www.cisa.gov/uscert/ics
www.cisa.gov/uscert/ics
www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01
www.cisa.gov/uscert/ics/recommended-practices
www.cisa.gov/uscert/ics/tips/ICS-TIP-12-146-01B
www.cisa.gov/uscert/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
www.dhs.gov
www.dhs.gov/foia
www.dhs.gov/performance-financial-reports
www.facebook.com/CISA
www.facebook.com/sharer/sharer.php?u=https://www.cisa.gov/news-events/ics-advisories/icsa-22-104-04&title=Siemens%20SCALANCE%20FragAttacks
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
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mailto:?subject=Siemens%20SCALANCE%20FragAttacks&body=www.cisa.gov/news-events/ics-advisories/icsa-22-104-04
6.5 Medium
CVSS3
Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7 High
AI Score
Confidence
High
3.3 Low
CVSS2
Access Vector
ADJACENT_NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:A/AC:L/Au:N/C:N/I:P/A:N
0.002 Low
EPSS
Percentile
64.3%