Siemens SICAM AK3/BC/TM

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 7.8
• ATTENTION: Low Attack Complexity
• Vendor: Siemens
• Equipment: SICAM AK3, SICAM BC and SICAM TM
• Vulnerability: Improper Null Termination

• 2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code or create a denial-of-service condition.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following products of Siemens, are affected:

• Siemens CPCX26 Central Processing/Communication: Versions prior to V06.02
• Siemens ETA4 Ethernet Interface IEC60870-5-104: Versions prior to V10.46
• Siemens ETA5 Ethernet Int. 1x100TX IEC61850 Ed.2: Versions prior to V03.27
• Siemens PCCX26 Ax 1703 PE, Contr, Communication Element: Versions prior to V06.05

3.2 Vulnerability Overview

3.2.1 IMPROPER NULL TERMINATION CWE-170

The affected device firmwares contain an improper null termination vulnerability while parsing a specific HTTP header. This could allow an attacker to execute code in the context of the current process or lead to denial-of-service condition.

CVE-2024-31484 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

A CVSS v4 score has also been calculated for CVE-2024-31484. A base score of 7.3 has been calculated; the CVSS vector string is (CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N).

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

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

• CPCX26 Central Processing/Communication: Update to V06.02 or later version.
  • The firmware CPCX26 V06.2 is present within "SICAM RTUs AK3 Package" V06.02
• PCCX26 Ax 1703 PE, Contr, Communication Element: Update to V06.05 or later version
  • The firmware PCCX26 V06.05 is present within "SICAM RTUs AK3 Package" V06.02
• ETA4 Ethernet Interface IEC60870-5-104: Update to V10.46 or later version
  • The firmware ETA4 V10.46 is present within "SICAM RTUs AK3 Package" V06.02
• ETA5 Ethernet Int. 1x100TX IEC61850 Ed.2: Update to V03.27 or later version
  • The firmware ETA5 V03.27 is present within "SICAM RTUs AK3 Package" V06.02

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-620338 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.

CISA also recommends users take the following measures to protect themselves from social engineering attacks:

• Do not click web links or open attachments in unsolicited email messages.
• Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
• Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.

No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability is not exploitable remotely.

5. UPDATE HISTORY

• June 13, 2024: Initial Publication

• Siemens