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 7.1
ATTENTION: Exploitable from adjacent network/low attack complexity
Vendor: Siemens
Equipment: SIMATIC, OpenPCS
Vulnerabilities: NULL Pointer Dereference

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to cause a persistent denial-of-service condition in the RPC Server of these products.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following products of Siemens, are affected:

OpenPCS 7 V9.1: All versions
SIMATIC BATCH V9.1: All versions
SIMATIC PCS 7 V9.1: All versions
SIMATIC Route Control V9.1: All versions
SIMATIC WinCC Runtime Professional V18: All versions
SIMATIC WinCC Runtime Professional V19: All versions
SIMATIC WinCC V7.4: All versions
SIMATIC WinCC V7.5: All versions prior to V7.5 SP2 Update 15
SIMATIC WinCC V8.0: All versions prior V8.0 SP4

3.2 Vulnerability Overview

3.2.1 NULL POINTER DEREFERENCE CWE-476

The implementation of the RPC (Remote Procedure call) communication protocol in the affected products do not properly handle certain unorganized RPC messages. An attacker could use this vulnerability to cause a denial-of-service condition in the RPC server.

CVE-2023-48363 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (CVSS3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

A CVSS v4 score has also been calculated for CVE-2023-48363. A base score of 7.1 has been calculated; the CVSS vector string is (CVSS4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N).

3.2.2 NULL POINTER DEREFERENCE CWE-476

The implementation of the RPC (Remote Procedure call) communication protocol in the affected products do not properly handle certain malformed RPC messages. An attacker could use this vulnerability to cause a denial-of-service condition in the RPC server.

CVE-2023-48364 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

A CVSS v4 score has also been calculated for CVE-2023-48364. A base score of 7.1 has been calculated; the CVSS vector string is (CVSS4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N).

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens ProductCERT reported these vulnerabilities to CISA.

4. MITIGATIONS

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

SIMATIC WinCC V7.5: Update to V7.5 SP2 Update 15 or later version
SIMATIC WinCC V8.0: Update to V8.0 SP4 or later version

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-753746 in HTML and CSAF.

CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities, 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). Recognize VPNs may have vulnerabilities, should be updated to the most recent version available, and are 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. 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 these vulnerabilities has been reported to CISA at this time. These vulnerabilities are not exploitable remotely.

5. UPDATE HISTORY

February 15, 2024: Initial Publication