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
7.8 High
AI Score
Confidence
High
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
0.001 Low
EPSS
Percentile
47.3%
This updated advisory is a follow-up to the advisory update titled ICSA-20-343-05 Siemens Embedded TCP/IP Stack Vulnerabilities–AMNESIA:33 (Update B) that was published March 9, 2021, to the ICS webpage on us-cert.cisa.gov.
Successful exploitation of this vulnerability could cause a denial-of-service condition.
The following products are affected:
An attacker located in the same network could trigger a denial-of-service condition on the device by sending a specially crafted IP packet.
CVE-2020-13988 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been calculated; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Daniel dos Santos, Stanislav Dashevskyi, Jos Wetzels, and Amine Amri of Forescout Research Labs reported this vulnerability to CISA.
Siemens recommends users upgrade affected products if upgrade are available for those products:
--------- Begin Update C Part 1 of 1 ---------
--------- End Update C Part 1 of 1 ---------
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 Siemens’ operational guidelines for industrial security and following the recommendations in the product manuals.
Additional information on industrial security by Siemens can be found at: <https://www.siemens.com/industrialsecurity>
For more information on this vulnerability and associated software updates, please see Siemens security advisory SSA-541017
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 us-cert.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 us-cert.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 this vulnerability.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-13988
cwe.mitre.org/data/definitions/190.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/ww/en/view/109759671/
support.industry.siemens.com/cs/ww/en/view/109760897/
support.industry.siemens.com/cs/ww/en/view/109761031/
support.industry.siemens.com/cs/ww/en/view/109765343/
support.industry.siemens.com/cs/ww/en/view/109793060/
support.industry.siemens.com/cs/ww/en/view/31674577
support.industry.siemens.com/cs/ww/en/view/31674577
twitter.com/CISAgov
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us-cert.cisa.gov/ics
us-cert.cisa.gov/ics
us-cert.cisa.gov/ics/alerts/ICS-ALERT-10-301-01
us-cert.cisa.gov/ics/recommended-practices
us-cert.cisa.gov/ics/tips/ICS-TIP-12-146-01B
us-cert.cisa.gov/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:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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www.oig.dhs.gov/
www.siemens.com/cert/advisories
www.siemens.com/cert/operational-guidelines-industrial-security
www.siemens.com/industrialsecurity
www.surveymonkey.com/r/CISA-cyber-survey?product=https://www.cisa.gov/news-events/ics-advisories/icsa-20-343-05
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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
7.8 High
AI Score
Confidence
High
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
0.001 Low
EPSS
Percentile
47.3%