CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:L/Au:N/C:P/I:N/A:N
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
85.2%
This updated advisory is a follow-up to the original advisory titled ICSA-20-252-06 Siemens SIMATIC HMI Products that was published September 8, 2020, to the ICS webpage on us-cert.cisa.gov.
Successful exploitation of these vulnerabilities could allow a remote attacker to discover user passwords and obtain access to the Sm@rt Server via a brute-force attack.
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The following versions of Siemens SIMATIC HMI Products are affected:
--------- End Update A Part 1 of 2 ---------
Affected devices insufficiently block excessive authentication attempts. This could allow a remote attacker to discover user passwords and obtain access to the Sm@rt Server via a brute-force attack.
CVE-2020-15786 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L).
Affected devices insufficiently validate authentication attempts as the information given can be truncated to match only a set number of characters versus the whole provided string. This could allow a remote attacker to discover user passwords and obtain access to the Sm@rt Server via a brute-force attack.
CVE-2020-15787 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).
Joseph Gardiner from Bristol Cyber Security Group, University of Bristol, reported these vulnerabilities to Siemens.
--------- Begin Update A Part 2 of 2 ---------
Siemens has released updates for the affected products and recommends users update to the latest versions.
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
--------- End Update A Part 2 of 2 ---------
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 following the recommendations in the product manuals.
For additional information, please refer to Siemens Security Advisory SSA-542525
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 these vulnerabilities.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-15786
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-15786
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-15786
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-15786
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-15787
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-15787
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/pdf/SSA-542525.pdf
cisasurvey.gov1.qualtrics.com/jfe/form/SV_9n4TtB8uttUPaM6?product=https://www.cisa.gov/news-events/ics-advisories/icsa-20-252-06
cwe.mitre.org/data/definitions/305.html
cwe.mitre.org/data/definitions/307.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/ww/en/view/109775861
support.industry.siemens.com/cs/ww/en/view/109775861
support.industry.siemens.com/cs/ww/en/view/109775861
support.industry.siemens.com/cs/ww/en/view/109775861
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us-cert.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
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www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
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CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
NONE
Availability Impact
NONE
AV:N/AC:L/Au:N/C:P/I:N/A:N
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
85.2%