5 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:L/Au:N/C:N/I:P/A:N
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
0.001 Low
EPSS
Percentile
49.8%
This updated advisory is a follow-up to the updated advisory titled ICSA-18-067-01 Siemens SIPROTEC 4, SIPROTEC Compact, DIGSI 4, and EN100 Ethernet Module (Update C) that was published March 12, 2019, to the ICS webpage on us-cert.cisa.gov.
Successful exploitation of these vulnerabilities could allow an attacker to upload a modified device configuration that could overwrite access authorization passwords, or allow an attacker to capture certain network traffic that could contain authorization passwords.
Siemens reports that the vulnerabilities affect the following products:
--------- Begin Update D Part 1 of 2 --------
--------- End Update D Part 1 of 2 --------
Successful exploitation of this vulnerability could allow an attacker to upload a modified device configuration, allowing an overwrite of access authorization passwords.
CVE-2018-4840 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:H/A:N).
Successful exploitation of this vulnerability could allow an attacker with local access to the engineering system or in a privileged network position to capture certain network traffic, and possibly reconstruct access authorization passwords.
CVE-2018-4839 has been assigned to this vulnerability. A CVSS v3 base score of 4.0 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N).
Ilya Karpov and Dmitry Sklyarov from Positive Technologies reported these vulnerabilities to Siemens.
Siemens has provided the following updates for mitigations:
--------- Begin Update D Part 2 of 2 --------
--------- End Update D 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.
Recommended security guidelines to secure substations and defense in depth can be found at: <https://www.siemens.com/gridsecurity>.
For more information on these vulnerabilities and associated software updates, please see Siemens security advisory SSA-203306
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-CERT web page. 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.
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/pdf/ssa-203306.pdf
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-4839
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-4840
cwe.mitre.org/data/definitions/306.html
cwe.mitre.org/data/definitions/326.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/us/en/view/109742699
support.industry.siemens.com/cs/us/en/view/109742712
support.industry.siemens.com/cs/us/en/view/109742758
support.industry.siemens.com/cs/us/en/view/109743551
support.industry.siemens.com/cs/us/en/view/109743555
support.industry.siemens.com/cs/us/en/view/109745821
support.industry.siemens.com/cs/us/en/view/109745821
support.industry.siemens.com/cs/ww/en/view/109740980
twitter.com/CISAgov
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us-cert.cisa.gov/ics/alerts/ICS-ALERT-10-301-01
us-cert.cisa.gov/ics/Recommended-Practices
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
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www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N
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5 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:L/Au:N/C:N/I:P/A:N
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
0.001 Low
EPSS
Percentile
49.8%