Hitachi Energy RTU500

1. EXECUTIVE SUMMARY

• CVSS v3 7.5
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Hitachi Energy
• Equipment: RTU500 Series
• Vulnerability: Stack-based Buffer Overflow

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to send a specially crafted Modbus TCP packet in a high rate, causing a stack overflow, which could result in a reboot of the product.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Hitachi Energy’s RTU500 firmware are affected:

• RTU500 series CMU Firmware version 12.0.1–12.0.13
• RTU500 series CMU Firmware version 12.2.1–12.2.11
• RTU500 series CMU Firmware version 12.4.1–12.4.11
• RTU500 series CMU Firmware version 12.6.1–12.6.7
• RTU500 series CMU Firmware version 12.7.1–12.7.3
• RTU500 series CMU Firmware version 13.2.1–13.2.4
• RTU500 series CMU Firmware version 13.3.1

3.2 VULNERABILITY OVERVIEW

3.2.1    STACK-BASED BUFFER OVERFLOW CWE-121

This vulnerability exists in the HCI Modbus TCP function in affected product versions. If the HCI Modbus TCP is enabled and configured, an attacker could exploit the vulnerability by sending a specially crafted message to the RTU500 in a high rate, causing the targeted RTU500 CMU to reboot. There is a lack of flood control, which if exploited, could cause an internal stack overflow in the HCI Modbus TCP function.

CVE-2022-2081 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Energy
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Switzerland

3.4 RESEARCHER

Hitachi Energy reported this vulnerability to CISA.

4. MITIGATIONS

Hitachi Energy recommends updating to the following firmware versions:

• Update to RTU500 series CMU Firmware version 12.0.14.0 or higher.
• Update to RTU500 series CMU Firmware version 12.2.12.0 or higher.
• Update to RTU500 series CMU Firmware version 12.4.12.0 or higher.
• Update to RTU500 series CMU Firmware version 12.6.8.0 or higher.
• Update to RTU500 series CMU Firmware version 12.7.4.0 or higher.
• Update to RTU500 series CMU Firmware version 13.2.5.0 or higher.
• Update to RTU500 series CMU Firmware version 13.3.2.0 or higher.

Users should see Hitachi Energy advisory 8DBD000111 for additional mitigation and update information.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls and isolate them from business networks.
• When remote access is required, use 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 its 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 at 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.

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 exploits specifically target this vulnerability.

• Hitachi Energy