CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:L/Au:N/C:P/I:P/A:P
CVSS3
Attack Vector
PHYSICAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
26.0%
This updated advisory is a follow-up to the advisory update titled-19-318-02 Siemens S7-1200 (Update A) that was published December 10, 2019, on the ICS webpage on us-cert.gov.
Successful exploitation of this vulnerability could expose additional diagnostic functionality to an attacker with physical access to the UART interface during boot process.
The following Siemens products are affected:
--------- Begin Update B Part 1 of 2 ---------
--------- End Update B Part 1 of 2 ---------
4.2.1 EXPOSED DANGEROUS METHOD OR FUNCTION CWE-749
An attacker with physical access to the UART interface could access additional diagnostic functionality. Successful exploitation could compromise confidentiality, integrity, and availability of the affected system.
CVE-2019-13945 has been assigned to this vulnerability. A CVSS v3 base score of 6.8 has been calculated; the CVSS vector string is
(AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Ali Abbasi from Ruhr University of Bochum reported this vulnerability to Siemens.
Siemens has identified the following specific mitigations for the referenced products:
--------- 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. Siemens recommends users configure their environment according to the Siemens Operational Guidelines for Industrial Security and follow the recommendations in the product manuals to operate the devices in a protected environment.
Additional information on industrial security by Siemens can be found at: https://www.siemens.com/industrialsecurity.
For further inquiries on security vulnerabilities in Siemens products, please contact the Siemens ProductCERT: http://www.siemens.com/cert/advisories.
For more information on the vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-686531 at the following location: http://www.siemens.com/cert/advisories.
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.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.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.
This vulnerability is not exploitable remotely; no known public exploits specifically target this vulnerability.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2019-13945
www.siemens.com/cert/advisories
www.siemens.com/cert/advisories
cisasurvey.gov1.qualtrics.com/jfe/form/SV_9n4TtB8uttUPaM6?product=https://www.cisa.gov/news-events/ics-advisories/icsa-19-318-02
cwe.mitre.org/data/definitions/749.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
twitter.com/CISAgov
twitter.com/intent/tweet?text=Siemens%20S7-1200%20and%20S7-200%20SMART%20CPUs%20%28Update%20B%29+https://www.cisa.gov/news-events/ics-advisories/icsa-19-318-02
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-19-318-02&title=Siemens%20S7-1200%20and%20S7-200%20SMART%20CPUs%20%28Update%20B%29
www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
www.instagram.com/cisagov
www.linkedin.com/company/cybersecurity-and-infrastructure-security-agency
www.linkedin.com/sharing/share-offsite/?url=https://www.cisa.gov/news-events/ics-advisories/icsa-19-318-02
www.oig.dhs.gov/
www.siemens.com/cert/operational-guidelines-industrial-security
www.siemens.com/cert/operational-guidelines-industrial-security
www.siemens.com/industrialsecurity
www.us-cert.gov/ics
www.us-cert.gov/ics
www.us-cert.gov/ics/alerts/ICS-ALERT-10-301-01
www.us-cert.gov/ics/recommended-practices
www.us-cert.gov/ics/tips/ICS-TIP-12-146-01B
www.us-cert.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
www.usa.gov/
www.whitehouse.gov/
www.youtube.com/@cisagov
mailto:?subject=Siemens%20S7-1200%20and%20S7-200%20SMART%20CPUs%20%28Update%20B%29&body=www.cisa.gov/news-events/ics-advisories/icsa-19-318-02
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:L/Au:N/C:P/I:P/A:P
CVSS3
Attack Vector
PHYSICAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
26.0%