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
40.3%
CVSS v3 5.3
ATTENTION: Exploitable remotely/low skill level to exploit
**Vendor:**Siemens
**Equipment:**SIMATIC S7
**Vulnerability:**Resource Exhaustion
This updated advisory is a follow-up to the original advisory titled ICSA-18-317-05 Siemens SIMATIC S7 that was published November 13, 2018, on the NCCIC/ICS-CERT website.
Successful exploitation of this vulnerability could result in a denial-of-service condition that could result in a loss of availability of the affected device.
Siemens reports the following SIMATIC S7 products are affected:
--------- Begin Update A Part 1 of 2 --------
--------- End Update A Part 1 of 2 ---------
4.2.1 UNCONTROLLED RESOURCE CONSUMPTION (βRESOURCE EXHAUSTIONβ) CWE-400
An attacker could exhaust the available connection pool of an affected device by opening a sufficient number of connections to the device. Successful exploitation requires an attacker to be able to send packets to Port 102/TCP of the affected device.
CVE-2018-13815 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).
Younes Dragoni of Nozomi Networks reported this vulnerability to Siemens.
Siemens recommends users of SIMATIC S7-1500 update to Version 2.6, which can be downloaded at the following location:
<https://support.industry.siemens.com/cs/de/en/view/109478459>
--------- Begin Update A Part 2 of 2 ---------
<https://support.industry.siemens.com/cs/us/en/view/109763919>
--------- 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-584286 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.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-13815
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cwe.mitre.org/data/definitions/400.html
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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
40.3%