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 9.8
ATTENTION: Exploitable remotely/low attack complexity
Vendor: Siemens
Equipment: Scalance W1750D
Vulnerabilities: Classic Buffer Overflow

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to exploit buffer overflow and information disclosure vulnerabilities which could lead to information disclosure or unauthenticated remote code execution.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following products of Siemens Scalance W1750D, a direct access point, are affected:

Siemens SCALANCE W1750D (JP) (6GK5750-2HX01-1AD0): All versions prior to V8.10.0.9
Siemens SCALANCE W1750D (ROW) (6GK5750-2HX01-1AA0): All versions prior to V8.10.0.9
Siemens SCALANCE W1750D (USA) (6GK5750-2HX01-1AB0): All versions prior to V8.10.0.9

3.2 Vulnerability Overview

3.2.1 BUFFER COPY WITHOUT CHECKING SIZE OF INPUT (‘CLASSIC BUFFER OVERFLOW’) CWE-120

There are buffer overflow vulnerabilities in multiple underlying services that could lead to unauthenticated remote code execution by sending specially crafted packets destined to the PAPI (Aruba’s access point management protocol) UDP port (8211). Successful exploitation of these vulnerabilities results in the ability to execute arbitrary code as a privileged user on the underlying operating system.

CVE-2023-35980 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).

3.2.2 BUFFER COPY WITHOUT CHECKING SIZE OF INPUT (‘CLASSIC BUFFER OVERFLOW’) CWE-120

There are buffer overflow vulnerabilities in multiple underlying services that could lead to unauthenticated remote code execution by sending specially crafted packets destined to the PAPI (Aruba’s access point management protocol) UDP port (8211). Successful exploitation of these vulnerabilities results in the ability to execute arbitrary code as a privileged user on the underlying operating system.

CVE-2023-35981 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).

3.2.3 BUFFER COPY WITHOUT CHECKING SIZE OF INPUT (‘CLASSIC BUFFER OVERFLOW’) CWE-120

There are buffer overflow vulnerabilities in multiple underlying services that could lead to unauthenticated remote code execution by sending specially crafted packets destined to the PAPI (Aruba’s access point management protocol) UDP port (8211). Successful exploitation of these vulnerabilities results in the ability to execute arbitrary code as a privileged user on the underlying operating system.

CVE-2023-35982 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).

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

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

Update to V8.10.0.9 or later version. The update is available upon request from customer support
The CLI and web-based management interfaces should be restricted to a dedicated layer 2 segment/VLAN and/or controlled by firewall policies at layer 3 and above
Enabling cluster-security via the cluster-security command will prevent the vulnerabilities from being exploited

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-885980 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), 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 these vulnerabilities has been reported to CISA at this time.

5. UPDATE HISTORY

April 11, 2024: Initial Publication