As of January 10, 2023, CISA will no longer be updating ICS security advisories for Siemens product vulnerabilities beyond the initial advisory. For the most up-to-date information on vulnerabilities in this advisory, please see Siemens' ProductCERT Security Advisories (CERT Services | Services | Siemens Global).

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1. EXECUTIVE SUMMARY

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow remote attackers to affect the availability of the devices under certain conditions.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Siemens reports that the following products are affected:

3.2 VULNERABILITY OVERVIEW

3.2.1 UNCONTROLLED RESOURCE CONSUMPTION CWE-400

The integrated ICMP service of the network stack of affected devices can be forced to exhaust its available memory resources when receiving specially crafted messages targeting IP fragment re-assembly. This could allow an unauthenticated remote attacker to cause a temporary denial-of-service condition of the ICMP service, other communication services are not affected. Affected devices will resume normal operation after the attack terminates.

CVE-2024-23814 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

A CVSS v4 score has also been calculated for CVE-2024-23814. A base score of 6.9 has been calculated; the CVSS vector string is (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N).

3.3 BACKGROUND

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

Siemens has identified the following specific workarounds and mitigations users can apply to reduce risk:

As a general security measure, Siemens 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 recommendations in the product manuals.

Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage

For more information see the associated Siemens security advisory SSA-725549 in HTML and CSAF.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as:

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 cisa.gov. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.

CISA also recommends users take the following measures to protect themselves from social engineering attacks:

No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.

5. UPDATE HISTORY