CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
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
39.3%
CVSS v3 5.3
ATTENTION: Exploitable remotely/low skill level to exploit
Vendor: Siemens
Equipment: SIMATIC S7-1500, SIMATIC S7-1500 Software Controller and SIMATIC ET 200SP Open Controller
Vulnerability: Improper Input Validation
This updated advisory is a follow-up to the original advisory titled ICSA-18-282-05 Siemens SIMATIC S7-1500, SIMATIC S7-1500 Software Controller and SIMATIC ET 200SP OpenController that was published October 9, 2018, on the NCCIC/ICS-CERT website.
An attacker with network access to the PLC may be able to cause a denial-of-service condition on the network stack.
Siemens reports that this vulnerability affects the following products and versions:
--------- Begin Update A Part 1 of 2 ---------
--------- End Update A Part 1 of 2 ---------
An attacker can cause a denial-of-service condition on the network stack by sending a large number of specially crafted packets to the PLC. The PLC will lose its ability to communicate over the network. This vulnerability could be exploited by an attacker with network access to the affected systems. Successful exploitation requires no privileges and no user interaction. An attacker could use this vulnerability to compromise availability of the network connectivity.
CVE-2018-13805 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).
Marcin Dudek, Jacek Gajewski, Kinga Staszkiewicz, Jakub Suchorab, and Joanna Walkiewicz from National Centre for Nuclear Research Poland reported this vulnerability to Siemens.
Siemens provides updates to address this vulnerability in these products and recommends users update to the new version.
<https://support.industry.siemens.com/cs/us/en/view/109478528>
<https://support.industry.siemens.com/cs/us/en/ps/13717/dl>
--------- Begin Update A Part 2 of 2--------
<https://support.industry.siemens.com/cs/us/en/view/109759122>
--------- End Update A 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 Siemensβ operational guidelines for industrial security (<https://www.siemens.com/cert/operational-guidelines-industrial-security>), and following the recommendations in the product manuals.
Additional information on Industrial Security by Siemens can be found at:
<https://www.siemens.com/industrialsecurity>
For more information on this vulnerability and associated software updates, please see Siemens security advisory SSA-347726 on their website:
<https://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 this vulnerability.
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CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
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
39.3%