7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.6 High
AI Score
Confidence
High
7.8 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
0.974 High
EPSS
Percentile
99.9%
This updated advisory is a follow-up to the advisory update titled ICSA-19-253-04 Siemens Industrial Products (Update Q) published on April 14, 2022 to the ICS webpage on cisa.gov/ics.
Successful exploitation of these vulnerabilities could cause denial-of-service condition.
Siemens reports the vulnerabilities affect the following industrial products:
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The kernel can be forced to make very expensive calls for every incoming TCP Selective Acknowledgement (SACK) packet which can lead to a denial-of-service condition.
CVE-2019-8460 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
The kernel is affected by an integer overflow when handling TCP Selective Acknowledgements, which could allow a remote attacker to cause a denial-of-service condition.
CVE-2019-11477 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
A remote attacker sending specially crafted TCP Selective Acknowledgment (SACK) sequences may cause a denial-of-service condition.
CVE-2019-11478 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).
An attacker may exploit a vulnerability in the TCP retransmission queue implementation kernel when handling TCP Selective Acknowledgements (SACK) to cause a denial-of-service condition.
CVE-2019-11479 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).
Siemens reported theses vulnerabilities to CISA.
Siemens recommends users follow the specific workarounds and mitigations below. Siemens has also released fixes for the following products:
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Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
As a general security measure, Siemens strongly recommends users protect network access to devices with As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for industrial security and following recommendations in the product manuals.
Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage.
For more information, please see Siemens Security Advisory SSA-462066
CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities. 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/ics. 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 e ICS webpage on cisa.gov/ics 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-2019-11477
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2019-11478
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2019-11479
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2019-8460
cert-portal.siemens.com/productcert/pdf/ssa-462066.pdf
cisa.gov/ics
cisa.gov/ics
cwe.mitre.org/data/definitions/1049.html
cwe.mitre.org/data/definitions/190.html
cwe.mitre.org/data/definitions/400.html
cwe.mitre.org/data/definitions/400.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/document/109756957
support.industry.siemens.com/cs/document/109773485
support.industry.siemens.com/cs/document/109773486
support.industry.siemens.com/cs/document/109773487
support.industry.siemens.com/cs/document/109774204
support.industry.siemens.com/cs/document/109774207/
support.industry.siemens.com/cs/document/109774207/
support.industry.siemens.com/cs/document/109775640
support.industry.siemens.com/cs/document/109775640
support.industry.siemens.com/cs/document/109775642
support.industry.siemens.com/cs/document/109775642
support.industry.siemens.com/cs/document/109778305
support.industry.siemens.com/cs/document/109778305
support.industry.siemens.com/cs/document/109778537
support.industry.siemens.com/cs/ww/en/view/109761495
support.industry.siemens.com/cs/ww/en/view/109769636
support.industry.siemens.com/cs/ww/en/view/109769665
support.industry.siemens.com/cs/ww/en/view/109773308
support.industry.siemens.com/cs/ww/en/view/109775642
support.industry.siemens.com/cs/ww/en/view/109777247
support.industry.siemens.com/cs/ww/en/view/109778052
support.industry.siemens.com/cs/ww/en/view/109781070
support.industry.siemens.com/cs/ww/en/view/109781665
support.industry.siemens.com/cs/ww/en/view/109781769
support.industry.siemens.com/cs/ww/en/view/109783768
support.industry.siemens.com/cs/ww/en/view/109798403
support.industry.siemens.com/cs/ww/en/view/109804739
support.industry.siemens.com/cs/ww/en/view/109804739
support.industry.siemens.com/cs/ww/en/view/109808361
support.industry.siemens.com/cs/ww/en/view/109808794
support.industry.siemens.com/cs/ww/en/view/109808796
twitter.com/CISAgov
twitter.com/intent/tweet?text=Siemens%20Industrial%20Products%20%28Update%20R%29+https://www.cisa.gov/news-events/ics-advisories/icsa-19-253-03
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
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www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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mailto:?subject=Siemens%20Industrial%20Products%20%28Update%20R%29&body=www.cisa.gov/news-events/ics-advisories/icsa-19-253-03
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.6 High
AI Score
Confidence
High
7.8 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
0.974 High
EPSS
Percentile
99.9%