CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
12.6%
This updated advisory is a follow-up to the original advisory titled ICSA-21-194-06 Siemens SIMATIC Software Products (Update A) that was published July 13, 2021, to the ICS webpage on cisa.gov/ics
Successful exploitation of this vulnerability could allow an attacker to manipulate parameters or the behavior of devices configured by the affected software products.
Siemens reports this vulnerability affects the following SIMATIC software products:
--------- Begin Update B Part 1 of 2 ---------
--------- End Update B Part 1 of 2 ---------
An attacker could change the content of certain metafiles and subsequently manipulate parameters or the behavior of devices that would be later configured by the affected software.
CVE-2021-31894 has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L).
Siemens reported this vulnerability to CISA.
Siemens has released updates for the following product:
--------- Begin Update B Part 2 of 2 ---------
--------- End Update B 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 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
Please see Siemens Security Advisory ssa-661034 for more information.
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. This vulnerability is not exploitable remotely.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-31894
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/pdf/ssa-661034.pdf
cisasurvey.gov1.qualtrics.com/jfe/form/SV_9n4TtB8uttUPaM6?product=https://www.cisa.gov/news-events/ics-advisories/icsa-21-194-06
cwe.mitre.org/data/definitions/732.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/de/en/view/109794088/
support.industry.siemens.com/cs/ww/en/view/109800526/
support.industry.siemens.com/cs/ww/en/view/109811911/
support.industry.siemens.com/cs/ww/en/view/109812240/
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:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L
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mailto:?subject=Siemens%20SIMATIC%20Software%20Products%20%28Update%20B%29&body=www.cisa.gov/news-events/ics-advisories/icsa-21-194-06
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
12.6%