CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:P/I:P/A:N
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
AI Score
Confidence
High
EPSS
Percentile
74.6%
This updated advisory is a follow-up to the advisory update titled ICSA-21-131-03 Siemens Linux-based Products (Update I) that was published August 11, 2022, to the ICS webpage at www.cisa.gov/ics.
Successful exploitation of this vulnerability could compromise confidentiality and integrity.
The following Siemens Linux-based products are affected:
--------- Begin Update J Part 1 of 2 ---------
-------- End Update J Part 1 of 2 ----------
A flaw in ICMP packets in the Linux kernel may allow an attacker to quickly scan open UDP ports. This flaw allows an off-path remote attacker to effectively bypass source port UDP randomization. Software that relies on UDP source port randomization are indirectly affected as well.
CVE-2020-25705 has been assigned to this vulnerability. A CVSS v3 base score of 7.4 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N).
Siemens reported this vulnerability to CISA.
Siemens recommends applying updates where applicable:
--------- Begin Update J Part 2 of 2 ---------
-------- End Update J Part 2 of 2 ----------
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
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 configuring the environment according to the Siemens operational guidelines for industrial security and following the recommendations in the product manuals.
For additional information, please refer to Siemens Security Advisory SSA-324955
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.
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 this vulnerability. This vulnerability has a high attack complexity.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-25705
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/pdf/ssa-324955.pdf
cisasurvey.gov1.qualtrics.com/jfe/form/SV_9n4TtB8uttUPaM6?product=https://www.cisa.gov/news-events/ics-advisories/icsa-21-131-03
cwe.mitre.org/data/definitions/330.html
new.siemens.com/global/en/products/services/cert.html#SecurityPublications
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/de/en/109802805
support.industry.siemens.com/cs/de/en/view/109803672
support.industry.siemens.com/cs/de/en/view/109803672
support.industry.siemens.com/cs/de/en/view/109804366
support.industry.siemens.com/cs/de/en/view/109804366
support.industry.siemens.com/cs/de/en/view/109804366
support.industry.siemens.com/cs/de/en/view/109804366
support.industry.siemens.com/cs/de/en/view/109804366
support.industry.siemens.com/cs/de/en/view/109804366
support.industry.siemens.com/cs/us/en/view/109812218
support.industry.siemens.com/cs/us/en/view/109812218
support.industry.siemens.com/cs/us/en/view/109812218
support.industry.siemens.com/cs/us/en/view/109812218
support.industry.siemens.com/cs/ww/en/view/109793041
support.industry.siemens.com/cs/ww/en/view/109793790
support.industry.siemens.com/cs/ww/en/view/109794349
support.industry.siemens.com/cs/ww/en/view/109794349
support.industry.siemens.com/cs/ww/en/view/109794349
support.industry.siemens.com/cs/ww/en/view/109799584
support.industry.siemens.com/cs/ww/en/view/109799584
support.industry.siemens.com/cs/ww/en/view/109799604
support.industry.siemens.com/cs/ww/en/view/109799604/
support.industry.siemens.com/cs/ww/en/view/109800773
support.industry.siemens.com/cs/ww/en/view/109803418
support.industry.siemens.com/cs/ww/en/view/109803418
support.industry.siemens.com/cs/ww/en/view/109811116
twitter.com/CISAgov
twitter.com/intent/tweet?text=Siemens%20Linux-based%20Products%20%28Update%20J%29+https://www.cisa.gov/news-events/ics-advisories/icsa-21-131-03
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/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
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www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
www.instagram.com/cisagov
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www.linkedin.com/sharing/share-offsite/?url=https://www.cisa.gov/news-events/ics-advisories/icsa-21-131-03
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mailto:?subject=Siemens%20Linux-based%20Products%20%28Update%20J%29&body=www.cisa.gov/news-events/ics-advisories/icsa-21-131-03
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:P/I:P/A:N
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
AI Score
Confidence
High
EPSS
Percentile
74.6%