CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
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:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
72.8%
This updated advisory is a follow-up to the advisory update titled ICSA-16-348-05 SIEMENS S7-300/400 PLC Vulnerabilities (Update D) that was published January 25, 2018, to the ICS webpage on us-cert.gov.
Successful exploitation of these vulnerabilities could lead to a denial-of-service condition or result in credential disclosure.
The following products are affected:
--------- Begin Update E Part 1 of 1 ---------
An attacker with network access to Port 102/TCP (ISO-TSAP) or via Profibus could obtain credentials from the PLC if Protection-Level 2 is configured on the affected devices.
CVE-2016-9159 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).
Specially crafted packets sent to Port 80/TCP could cause the affected devices to go into defect mode. A cold restart is required to recover the system.
CVE-2016-9158 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).
--------- End Update E Part 1 of 1 ---------
Zhu WenZhe from Beijing Acorn Network Technology reported these vulnerabilities to CISA.
Siemens provides the following firmware versions to resolve CVE-2016-9158:
Siemens also recommends the following mitigations:
Siemens strongly recommends users protect network access with appropriate mechanisms (e.g., firewalls, segmentation, VPN). Siemens also advises that users configure the operational environment according to Siemensβ Operational Guidelines for Industrial Security.
For more information on these vulnerabilities and more detailed mitigation instructions, please see Siemens Security Advisory SSA-731239.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. 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.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.gov 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-2016-9158
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-9159
www.siemens.com/cert/advisories
cisasurvey.gov1.qualtrics.com/jfe/form/SV_9n4TtB8uttUPaM6?product=https://www.cisa.gov/news-events/ics-advisories/icsa-16-348-05
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/200.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/de/en/view/109474874
support.industry.siemens.com/cs/ww/en/ps/13752/dl
support.industry.siemens.com/cs/ww/en/view/109476571
support.industry.siemens.com/cs/ww/en/view/109752685
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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:N/A:N
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www.us-cert.gov/ics
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www.us-cert.gov/ics/alerts/ICS-ALERT-10-301-01
www.us-cert.gov/ics/recommended-practices
www.us-cert.gov/ics/tips/ICS-TIP-12-146-01B
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CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
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:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
72.8%