Hitachi Energy Relion 670/650/SAM600-IO (Update A)
1. EXECUTIVE SUMMARY
- CVSS v4 8.9
- ATTENTION: Exploitable locally
- Vendor: Hitachi Energy
- Equipment: Relion 670/650/SAM600-IO
- Vulnerability: Initialization of a Resource with an Insecure Default
2. RISK EVALUATION
Successful exploitation of this vulnerability could hijack existing TCP sessions to inject packets of their choosing or cause denial-of-service conditions.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Hitachi Energy reports this vulnerability affects the following Relion products:
- Relion 670/650 series: Version 2.2.0
- Relion 670/650/SAM600-IO series: Versions 2.2.1 through 2.2.1.6
- Relion 670 series: Versions 2.2.2 through 2.2.2.4
- Relion 670 series: Versions 2.2.3 through 2.2.3.3
- Relion 670/650 series: Versions 2.2.4 through 2.2.4.2
3.2 VULNERABILITY OVERVIEW
3.2.1 Initialization of a Resource with an Insecure Default CWE-1188
A vulnerability exists in the early boot process of the product in which there is a tiny time gap where a previous version of VxWorks is loaded prior to booting up the complete application firmware. The older version of VxWorks is susceptible to Urgent/11, which may allow for remote code execution on the device before the operating system is loaded.
CVE-2021-35535 has been assigned to this vulnerability. A CVSS v3.1 base score of 8.1 has been calculated; the CVSS vector string is (CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).
A CVSS v4 score has also been calculated for CVE-2021-35535. A base score of 8.9 has been calculated; the CVSS vector string is (CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H).
3.3 BACKGROUND
- CRITICAL INFRASTRUCTURE SECTORS: Energy
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Switzerland
3.4 RESEARCHER
A Department of Energy CyTRICS researcher from Idaho National Laboratory reported this vulnerability to Hitachi Energy.
4. MITIGATIONS
Hitachi Energy recommends the following actions to mitigate this vulnerability:
- Relion 670/650/SAM600-IO series Version 2.2.1: Update to Revision 2.2.1.7 or latest.
- Relion 670 series Version 2.2.2: Update to Revision 2.2.2.5 or latest.
- Relion 670 series Version 2.2.3: Update to Revision 2.2.3.4 or latest.
- Relion 670/650 series Version 2.2.4: Update to Revision 2.2.4.3 or latest.
Hitachi Energy recommends the following security practices and firewall configurations to help protect process control networks from attacks that originate from outside the network:
- Physically protect process control systems from direct access by unauthorized personnel.
- Do not directly connect to the Internet.
- Separate from other networks by means of a firewall system that has a minimal number of ports exposed.
- Process control systems should not be used for Internet surfing, instant messaging, or receiving e-mails.
- Portable computers and removable storage media should be carefully scanned for viruses before they are connected to a control system.
For additional mitigation and update information see Hitachi Energy cybersecurity advisory 8DBD000061.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. 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 this vulnerability has been reported to CISA at this time. This vulnerability has a high attack complexity.
5. UPDATE HISTORY
- December 02, 2021: Initial Republication of Hitachi Energy cybersecurity advisory 8DBD000061
- May 29, 2025: Update A - Affected Product Versions & Recommended Immediate Actions
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Vendor
- Hitachi Energy