9.8 High
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
9.4 High
AI Score
Confidence
High
10 High
CVSS2
Access Vector
Access Complexity
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:C/I:C/A:C
0.002 Low
EPSS
Percentile
56.6%
This updated advisory is a follow-up to the advisory update titled ICSA-21-012-05 Siemens SCALANCE X Products (Update A) that was published February 9, 2021, to the ICS webpage on us-cert.cisa.gov.
Successful exploitation of these vulnerabilities could cause denial-of-service conditions and further impact the system through heap and buffer overflows.
Siemens reports that these vulnerabilities affect the following SCALANCE X products:
--------- Begin Update B Part 1 of 2 ---------
--------- End Update B Part 1 of 2 ---------
This vulnerability could allow an unauthenticated attacker to reboot the device over the network using special URLs from integrated web server of the affected products.
CVE-2020-15799 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
The web server of the affected devices contains a vulnerability that may lead to a heap-overflow condition. An attacker could cause this condition on the web server by sending specially crafted requests. This could stop the web server temporarily.
CVE-2020-15800 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
The web server of the affected devices contains a vulnerability that may lead to a buffer-overflow condition. An attacker could cause this condition on the web server by sending a specially crafted request. The web server could stop and not recover.
CVE-2020-25226 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Siemens reported these vulnerabilities to CISA.
Siemens has released updates for several affected products and recommends updating to the latest version(s). Siemens recommends countermeasures where fixes are not currently available.
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--------- 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 the Siemens operational guidelines for Industrial Security and following the recommendations in the product manuals.
For additional information, please refer to Siemens Security Advisory SSA-139628
CISA recommends users take defensive measures to minimize the risk of exploitation of 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 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-2020-15799
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-15800
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-25226
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/pdf/ssa-139628.pdf
cwe.mitre.org/data/definitions/122.html
cwe.mitre.org/data/definitions/122.html
cwe.mitre.org/data/definitions/306.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/ww/en/view/109773547/
support.industry.siemens.com/cs/ww/en/view/109792534/
support.industry.siemens.com/cs/ww/en/view/109801131/
twitter.com/CISAgov
twitter.com/intent/tweet?text=Siemens%20SCALANCE%20X%20Products%20%28Update%20B%29+https://www.cisa.gov/news-events/ics-advisories/icsa-21-012-05
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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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mailto:?subject=Siemens%20SCALANCE%20X%20Products%20%28Update%20B%29&body=www.cisa.gov/news-events/ics-advisories/icsa-21-012-05
9.8 High
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
9.4 High
AI Score
Confidence
High
10 High
CVSS2
Access Vector
Access Complexity
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:C/I:C/A:C
0.002 Low
EPSS
Percentile
56.6%