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

CVSS v4 9.3
ATTENTION: Exploitable remotely/low attack complexity
Vendor: Siemens
Equipment: SENTRON 7KM PAC3200
Vulnerability: Improper Authentication

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to access clear text communication.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Siemens SENTRON PAC3200 devices are affected:

SENTRON 7KM PAC3200: All versions

3.2 Vulnerability Overview

3.2.1 IMPROPER AUTHENTICATION CWE-287

Affected devices only provide a 4-digit PIN to protect from administrative access via Modbus TCP interface. Attackers with access to the Modbus TCP interface could easily bypass this protection by brute-force attacks or by sniffing the Modbus clear text communication.

CVE-2024-41798 has been assigned to this vulnerability. A CVSS v3.1 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

A CVSS v4 score has also been calculated for CVE-2024-41798. A base score of 9.3 has been calculated; the CVSS vector string is (CVSS4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N).

3.3 BACKGROUND

CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
COUNTRIES/AREAS DEPLOYED: Worldwide
COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Michael Messner from Siemens Energy reported this vulnerability to Siemens. Siemens reported this vulnerability to CISA.

4. MITIGATIONS

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

SENTRON 7KM PAC3200: Currently no fix is planned
Consider the PIN as protection against unauthorized operation (i.e., protection against inadvertent operating errors), not as protection against malicious access attempts, such as through brute-force attacks; for details see the FAQ article at https://support.industry.siemens.com/cs/ww/en/view/109975235/

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-850560 in HTML and CSAF.

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

Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
Locate control system networks and remote devices behind firewalls and isolating them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.

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/ics. 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/ics 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.

5. UPDATE HISTORY

October 10, 2024: Initial Publication