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
0.001 Low
EPSS
Percentile
36.9%
As of January 10, 2023, CISA will no longer be updating ICS security advisories for Siemens product vulnerabilities beyond the initial advisory. For the most up-to-date information on vulnerabilities in this advisory, please see Siemens’ ProductCERT Security Advisories (CERT Services | Services | Siemens Global).
Successful exploitation of these vulnerabilities could result in a remote attacker causing a denial-of-service condition on the affected devices.
The following software from Siemens is affected:
Affected devices do not correctly process certain specially crafted packets sent to port 102/TCP, which could allow an attacker to cause a denial-of-service condition on the device.
CVE-2021-40365 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated. the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Affected devices do not correctly process certain specially crafted packets sent to port 102/TCP, which could allow an attacker to cause a denial-of-service condition on the device.
CVE-2021-44693 has been assigned to this vulnerability. A CVSS v3 base score of 4.9 has been calculated. the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H)
Affected devices do not correctly process certain specially crafted packets sent to port 102/TCP, which could allow an attacker to cause a denial-of-service condition on the device.
CVE-2021-44694 has been assigned to this vulnerability. A CVSS v3 base score of 5.5 has been calculated. the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:H)
Affected devices do not correctly process certain specially crafted packets sent to port 102/TCP, which could allow an attacker to cause a denial-of-service condition on the device.
CVE-2021-44695 has been assigned to this vulnerability. A CVSS v3 base score of 4.9 has been calculated. the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H)
Gao Jian reported these vulnerabilities to Siemens.
Siemens released updates for several affected products and recommends updating to the latest versions. Siemens is preparing further updates and recommends countermeasures for products where updates are not, or not yet, available.
Siemens has identified the following specific workarounds and mitigations users can apply to reduce risk:
As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. 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 here.
For further inquiries on security vulnerabilities in Siemens products, users should contact Siemens ProductCERT.
For more information, see the associated Siemens security advisory SSA-382653 in HTML and CSAF.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability these vulnerabilities. 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 at cisa.gov/ics. Several CISA products detailing cyber defense best 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 at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploits specifically target these vulnerabilities.
cert-portal.siemens.com/productcert/csaf/ssa-382653.json
cert-portal.siemens.com/productcert/html/ssa-382653.html
cisa.gov/ics
cisa.gov/ics
cwe.mitre.org/data/definitions/1284.html
cwe.mitre.org/data/definitions/1286.html
cwe.mitre.org/data/definitions/1287.html
cwe.mitre.org/data/definitions/20.html
new.siemens.com/global/en/products/services/cert.html#SecurityPublications
nvd.nist.gov/vuln/detail/CVE-2021-40365
nvd.nist.gov/vuln/detail/CVE-2021-44693
nvd.nist.gov/vuln/detail/CVE-2021-44694
nvd.nist.gov/vuln/detail/CVE-2021-44695
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/ww/en/view/109478459/
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us-cert.cisa.gov/ics/Recommended-Practices
us-cert.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01
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