5.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
7.2 High
AI Score
Confidence
High
4.3 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:N/I:N/A:P
0.003 Low
EPSS
Percentile
70.9%
This updated advisory is a follow-up to the original advisory titled ICSA-22-104-05 Siemens OpenSSL Vulnerabilities in Industrial Products (Update A) that was published May 12, 2022, on the ICS webpage at cisa.gov/ics.
Successful exploitation of this vulnerability may allow an unauthenticated attacker to cause a denial-of-service condition if a maliciously crafted renegotiation message is sent.
Siemens reports this vulnerability affects the following products:
--------- Begin Update B Part 1 of 1 ---------
--------- End Update B Part 1 of 1 ---------
An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension, where it was present in the initial ClientHello, but includes a signature_algorithms_cert extension, then a NULL pointer dereference will occur, leading to a crash and a denial-of-service condition.
A server is only vulnerable if it has TLSv1.2 and renegotiation enabled, which is the default configuration. OpenSSL TLS clients are not impacted by this issue. All OpenSSL 1.1.1 versions are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. This vulnerability is fixed in OpenSSL 1.1.1k.
CVE-2021-3449 has been assigned to this vulnerability. A CVSS v3 base score of 5.9 has been calculated. the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H)
Siemens reported this vulnerability to CISA.
Siemens has released updates for several affected products and recommends updating to the latest versions available. Siemens is preparing further updates and recommends countermeasures for products where updates are not, or not yet available. Please see Siemens SSA-772220 to determine if there is an update available.
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 to follow the recommendations in the product manuals. 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 and solutions, please contact Siemens.
Additional Reference: SSA-772220 (PDF)
Additional Reference: SSA-772220 (TXT)
Additional Reference: SSA-772220 (CSAF)
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/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 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 this vulnerability.
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/csaf/ssa-772220.json
cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf
cert-portal.siemens.com/productcert/txt/ssa-772220.txt
cert-portal.siemens.com/productcert/txt/ssa-772220.txt
cisa.gov/ics
cisa.gov/ics
cwe.mitre.org/data/definitions/476.html
new.siemens.com/global/en/products/services/cert.html#SecurityPublications
nvd.nist.gov/vuln/detail/CVE-2021-3449
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
twitter.com/CISAgov
twitter.com/intent/tweet?text=Siemens%20OpenSSL%20Vulnerabilities%20in%20Industrial%20Products%20%28Update%20B%29+https://www.cisa.gov/news-events/ics-advisories/icsa-22-104-05
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
www.dhs.gov/performance-financial-reports
www.facebook.com/CISA
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www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
www.instagram.com/cisagov
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www.linkedin.com/sharing/share-offsite/?url=https://www.cisa.gov/news-events/ics-advisories/icsa-22-104-05
www.oig.dhs.gov/
www.siemens.com/cert/advisories
www.siemens.com/industrialsecurity
www.surveymonkey.com/r/CISA-cyber-survey?product=https://www.cisa.gov/news-events/ics-advisories/icsa-22-104-05
www.usa.gov/
www.whitehouse.gov/
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mailto:?subject=Siemens%20OpenSSL%20Vulnerabilities%20in%20Industrial%20Products%20%28Update%20B%29&body=www.cisa.gov/news-events/ics-advisories/icsa-22-104-05
5.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
7.2 High
AI Score
Confidence
High
4.3 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:N/I:N/A:P
0.003 Low
EPSS
Percentile
70.9%