Siemens User Management Component (UMC)

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: SIMATIC Information Server, SIMATIC PCS neo, SINEC NMS, Totally Integrated Automation Portal (TIA Portal)
• Vulnerability: Heap-based Buffer Overflow

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an unauthenticated remote attacker to achieve arbitrary code execution.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following Siemens User Managements Components are affected:

• SIMATIC Information Server 2022: All versions
• SIMATIC Information Server 2024: All versions
• SIMATIC PCS neo V4.0: All versions
• SIMATIC PCS neo V4.1: All versions prior to V4.1 Update 2
• SIMATIC PCS neo V5.0: All versions
• SINEC NMS: All versions
• Totally Integrated Automation Portal (TIA Portal) V16: All versions
• Totally Integrated Automation Portal (TIA Portal) V17: All versions prior to V17 Update 8
• Totally Integrated Automation Portal (TIA Portal) V18: All versions
• Totally Integrated Automation Portal (TIA Portal) V19: All versions

3.2 Vulnerability Overview

3.2.1 HEAP-BASED BUFFER OVERFLOW CWE-122

Affected products contain a heap-based buffer overflow vulnerability in the integrated UMC component. This could allow an unauthenticated remote attacker to execute arbitrary code.

CVE-2024-33698 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-2024-33698. 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

Tenable 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:

• SIMATIC Information Server 2022: Currently no fix is available
• SIMATIC Information Server 2024: Currently no fix is available
• SIMATIC PCS neo V4.0: Currently no fix is available
• SIMATIC PCS neo V4.1: Update to V4.1 Update 2 or later version
• SIMATIC PCS neo V5.0: Currently no fix is available
• SINEC NMS: Update UMC to V2.11.6
• Totally Integrated Automation Portal (TIA Portal) V16: Currently no fix is available
• Totally Integrated Automation Portal (TIA Portal) V17: Update to V17 Update 8 or later version
• Totally Integrated Automation Portal (TIA Portal) V18: Update UMC to V2.13.1 as delivered via TIA Portal V17 Update 8
• Totally Integrated Automation Portal (TIA Portal) V19: Update UMC to V2.13.1 as delivered via TIA Portal V17 Update 8
• Filter the ports 4002 and 4004 to only accept connections to/from the IP addresses of machines
  that run UMC and are part of the UMC network e.g. with an external firewall
• In addition if no RT server machines are used, port 4004 can be filtered completely

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-039007 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

• September 12, 2024: Initial Publication

• Siemens