Siemens Web Server of Industrial Products

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 v3 7.5
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Siemens
• Equipment: SIMATIC CP, SINAMICS, SIPLUS NET CP
• Vulnerability: Missing Release of Memory after Effective Lifetime

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an unauthorized attacker with network access to the web server of an affected device to perform a denial-of-service attack.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following products of Siemens, are affected:

• SIMATIC CP 1242-7 V2 (incl. SIPLUS variants): All versions
• SIMATIC CP 1243-1 (incl. SIPLUS variants): All versions
• SIMATIC CP 1243-1 DNP3 (incl. SIPLUS variants): All versions
• SIMATIC CP 1243-1 IEC (incl. SIPLUS variants): All versions
• SIMATIC CP 1243-7 LTE: All versions
• SIMATIC CP 1243-8 IRC (6GK7243-8RX30-0XE0): All versions
• SIMATIC CP 1543-1 (6GK7543-1AX00-0XE0): All versions
• SINAMICS S210 (6SL5...): Versions V6.1 up to but not including V6.1 HF2
• SIPLUS NET CP 1543-1 (6AG1543-1AX00-2XE0): All versions

3.2 Vulnerability Overview

3.2.1 MISSING RELEASE OF MEMORY AFTER EFFECTIVE LIFETIME CWE-401

The webserver implementation of the affected products does not correctly release allocated memory after it has been used. An attacker with network access could use this vulnerability to cause a denial-of-service condition in the webserver of the affected product.

CVE-2023-38380 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 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:H).

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

Siemens has released a new version for SINAMICS S210 (6SL5...) and

recommends users update to the latest version. Siemens is preparing

further fix versions and recommends specific countermeasures for

products where fixes are not, or not yet available.

• SINAMICS S210 (6SL5...): Update to V6.1 HF2 or later version

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

• Restrict network access to the integrated webserver

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-693975 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). 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 this vulnerability has been reported to CISA at this time.

5. UPDATE HISTORY

• December 14, 2023: Initial Publication

• Siemens