7.5 High
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
9.9 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.5 High
AI Score
Confidence
Low
0.001 Low
EPSS
Percentile
47.9%
This updated advisory is a follow-up to the advisory update titled ICSA-21-315-03 Siemens SIMATIC WinCC (Update D) that was published April 14, 2022, to the ICS webpage on cisa.gov/ics.
Successful exploitation of these vulnerabilities could allow local attackers to escalate privileges, and read, write, or delete critical files.
Siemens reports these vulnerabilities affects the following SIMATIC SCADA HMI system products:
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Legitimate file operations of the affected systems do not properly neutralize special elements within the pathname. An attacker could cause the pathname to resolve to a location outside of the restricted directory on the server and read, write, or delete critical files.
CVE-2021-40358 has been assigned to this vulnerability. A CVSS v3 base score of 9.9 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).
When downloading files, the affected systems do not properly neutralize special elements within the pathname. An attacker could cause the pathname to resolve to a location outside of the restricted directory on the server and read critical files.
CVE-2021-40359 has been assigned to this vulnerability. A CVSS v3 base score of 7.7 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N).
The affected systems store sensitive information in log files. An attacker with access to the log files could publicly expose the information or reuse it to develop further attacks.
CVE-2021-40364 has been assigned to this vulnerability. A CVSS v3 base score of 5.5 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).
Thomas Riedmaier from Siemens Energy reported these vulnerabilities to Siemens.
Siemens has released updates for several affected products and recommends updating to the latest versions. Siemens is preparing further updates and recommends specific countermeasures for products where updates are not, or not yet, available.
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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 Siemensβ operational guidelines for Industrial Security, and follow the recommendations in the product manuals.
For more information about this issue, please see Siemens security advisory SSA-840188
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 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-12-146-01BβTargeted 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-2021-40358
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-40359
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-40364
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/pdf/ssa-840188.pdf
cisa.gov/ics
cisa.gov/ics
cwe.mitre.org/data/definitions/22.html
cwe.mitre.org/data/definitions/22.html
cwe.mitre.org/data/definitions/532.html
new.siemens.com/global/en/products/services/cert.html#SecurityPublications
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/us/en/view/109763890/
support.industry.siemens.com/cs/us/en/view/109776017/
support.industry.siemens.com/cs/us/en/view/109784441/
support.industry.siemens.com/cs/us/en/view/109793460/
support.industry.siemens.com/cs/ww/de/view/109808270/
support.industry.siemens.com/cs/ww/en/view/109780528/
support.industry.siemens.com/cs/ww/en/view/109780528/
support.industry.siemens.com/cs/ww/en/view/109805073/
support.industry.siemens.com/cs/ww/en/view/109805073/
support.industry.siemens.com/cs/ww/en/view/109805073/
support.industry.siemens.com/cs/ww/en/view/109805073/
support.industry.siemens.com/cs/ww/en/view/109806846/
support.industry.siemens.com/cs/ww/en/view/109806846/
support.industry.siemens.com/cs/ww/en/view/109806846/
support.industry.siemens.com/cs/ww/en/view/109806846/
support.industry.siemens.com/cs/ww/en/view/109811815/
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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
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mailto:?subject=Siemens%20SIMATIC%20WinCC%20%28Update%20E%29&body=www.cisa.gov/news-events/ics-advisories/icsa-21-315-03
7.5 High
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
9.9 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.5 High
AI Score
Confidence
Low
0.001 Low
EPSS
Percentile
47.9%