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).
Successful exploitation of this vulnerability could cause the network access server to grant the attacker access to the network with the attacker's desired authorization and without the need of knowing or guessing legitimate access credentials.
Siemens reports the following products using the RADIUS protocol are affected:
The RADIUS Protocol under RFC 2865 is susceptible to forgery attacks by a local attacker who can modify responses Access-Reject or Access-Accept using a chosen-prefix collision attack against MD5 Response Authenticator signature.
CVE-2024-3596 has been assigned to this vulnerability. A CVSS v3.1 base score of 9.0 has been calculated; the CVSS vector string is (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).
A CVSS v4 score has also been calculated for CVE-2024-3596. A base score of 9.1 has been calculated; the CVSS vector string is (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H).
Siemens reported this vulnerability to CISA.
Siemens has released new versions for several of the affected products and recommends updating to the latest versions and configuring the updated systems as follows. Siemens is preparing additional fix versions and recommends specific countermeasures for products where fixes are not yet available.
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-794185 in HTML and CSAF.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. 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.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.