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
59.8%
CVSS v3 7.5
ATTENTION: Exploitable remotely/low skill level to exploit
**Vendor:**Siemens
**Equipment:**SIMATIC S7-1500 CPU
Vulnerabilities: Improper Input Validation
Successful exploitation of these vulnerabilities could allow a denial of service condition of the device.
The following versions of SIMATIC S7-1500 CPU are affected:
3.2.1 IMPROPER INPUT VALIDATION CWE-20
An unauthenticated attacker sending specially crafted network packets to Port 80/tcp or 443/tcp may cause a denial of service on the device.
CVE-2018-16558 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).
3.2.2 IMPROPER INPUT VALIDATION CWE-20
An unauthenticated attacker sending specially crafted network packets to Port 80/tcp or 443/tcp may cause a denial of service on the device.
CVE-2018-16559 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).
Georgy Zaytsev, Dmitry Sklyarov, Druzhinin Evgeny, Ilya Karpov, and Maxim Goryachy of Positive Technologies reported these vulnerabilities to Siemens.
Siemens recommends users upgrade to Version 2.5 or newer. Users who cannot upgrade because of hardware restrictions are recommended to apply the manual mitigations. Updates are available for download from the following link:
<https://support.industry.siemens.com/cs/de/en/view/109478459>
Siemens also recommends users apply the following manual mitigations:
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 (Download: <https://www.siemens.com/cert/operational-guidelines-industrial-security>) and following the recommendations in the product manuals.
Additional information on industrial security for Siemens devices can be found at:
<https://www.siemens.com/Industrialsecurity>
For more information on these vulnerabilities and more detailed mitigation instructions, please see Siemens Security Advisory SSA-180635 at the following location:
<http://www.siemens.com/cert/advisories>
NCCIC recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
NCCIC 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-CERT website 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 NCCIC for tracking and correlation against other incidents.
No known public exploits specifically target these vulnerabilities.
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/20.html
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-16558
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-16559
www.siemens.com/cert/advisories
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public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
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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
59.8%