Siemens InterMesh Subscriber Devices

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 10.0
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Siemens
• Equipment: InterMesh
• Vulnerabilities: OS Command Injection, Missing Authentication for Critical Function, Execution with Unnecessary Privileges, Incorrect Privilege Assignment

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to perform remote code execution, execute commands, write arbitrary files, or execute arbitrary commands.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Siemens InterMesh Subscriber Devices, a wireless alarm reporting system, are affected:

• InterMesh 7177 Hybrid 2.0 Subscriber: All versions prior to V8.2.12
• InterMesh 7707 Fire Subscriber: All versions prior to V7.2.12

3.2 Vulnerability Overview

3.2.1 IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS USED IN AN OS COMMAND ('OS COMMAND INJECTION') CWE-78

The web server of affected devices does not sanitize the input parameters in specific GET requests that allow for code execution on operating system level. In combination with other vulnerabilities (CVE-2024-47902, CVE-2024-47903, CVE-2024-47904) this could allow an unauthenticated remote attacker to execute arbitrary code with root privileges.

CVE-2024-47901 has been assigned to this vulnerability. A CVSS v3.1 base score of 10.0 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).

A CVSS v4 score has also been calculated for CVE-2024-47901. A base score of 10.0 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:H/SI:H/SA:H).

3.2.2 MISSING AUTHENTICATION FOR CRITICAL FUNCTION CWE-306

The web server of affected devices does not authenticate GET requests that execute specific commands (such as ping) on operating system level.

CVE-2024-47902 has been assigned to this vulnerability. A CVSS v3.1 base score of 7.2 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N).

A CVSS v4 score has also been calculated for CVE-2024-47902. A base score of 6.9 has been calculated; the CVSS vector string is (CVSS4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N).

3.2.3 EXECUTION WITH UNNECESSARY PRIVILEGES CWE-250

The web server of affected devices allows to write arbitrary files to the web server's DocumentRoot directory.

CVE-2024-47903 has been assigned to this vulnerability. A CVSS v3.1 base score of 5.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N).

A CVSS v4 score has also been calculated for CVE-2024-47903. A base score of 6.9 has been calculated; the CVSS vector string is (CVSS4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N).

3.2.4 INCORRECT PRIVILEGE ASSIGNMENT CWE-266

The affected devices contain a SUID binary that could allow an authenticated local attacker to execute arbitrary commands with root privileges.

CVE-2024-47904 has been assigned to this vulnerability. A CVSS v3.1 base score of 7.8 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

A CVSS v4 score has also been calculated for CVE-2024-47904. A base score of 8.5 has been calculated; the CVSS vector string is (CVSS4.0/AV:L/AC:L/AT:N/PR:L/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

AES Corporation and Jean Pereira from CYTRES reported these vulnerabilities to Siemens. Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

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

• InterMesh 7177 Hybrid 2.0 Subscriber: Update to V8.2.12 or later version
• InterMesh 7707 Fire Subscriber: Update to V7.2.12 or later version
• Restrict access to the InterMesh network to trusted systems and persons only

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-333468 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

• October 29, 2024: Initial Publication

• Siemens