In a world increasingly reliant on digital control systems, the security of industrial devices is a pressing topic that spans energy utilities, manufacturers, and critical infrastructure operators worldwide. Recent revelations have put the spotlight squarely on Hitachi Energy’s Relion 670 and 650 series and the SAM600-IO series—key components in global energy distribution systems—after the discovery of a remote exploitation vulnerability that has the potential to compromise sensitive communications built atop OpenSSL’s widely used cryptographic libraries.
A vulnerability referred to as an “Observable Discrepancy” (CWE-203) forms the basis of this security concern. As detailed in CVE-2022-4304, the affected Hitachi Energy devices employ an OpenSSL RSA decryption implementation susceptible to a classic timing-based side-channel attack. When exploited, this flaw can potentially allow an attacker to recover plaintext transmitted across a network—effectively enabling the decryption of sensitive data in transit and opening doors to a host of further intrusions.
The vulnerability earned a CVSS v4 base score of 8.2, indicative of its high impact albeit somewhat mitigated by a high attack complexity. Notably, earlier assessments under the CVSS v3 standard scored the vulnerability at a lower 5.9, reflecting evolving risk assessment methodologies. Critically, this flaw is remotely exploitable; no physical access or user interaction is required, dramatically raising the stakes for utilities and industrial organizations deploying these systems.
While the attack requires a sophisticated understanding of cryptographic principles and a substantial volume of traffic to perform successfully, history has repeatedly shown that such theoretical risks become practical with increasingly automated attack toolsets and readily available cloud computing resources. Additionally, as OpenSSL’s RSA implementation underpins not just TLS-secured device management but potentially other secure channels within these devices, the broader ramifications are serious.
Breaches of such systems could expose power grid control networks to eavesdropping, data manipulation, or even direct disruption. Recent history—including incidents like the 2015 Ukrainian power grid cyberattack—has demonstrated the tangible threat posed by cyberattacks on industrial energy systems. It cannot be overstated: vulnerabilities in these devices are not abstractions; they have the potential for real-world blackouts, economic disruptions, or worse.
The cited vulnerability affects all RSA padding modes used by OpenSSL in the affected versions. This includes PKCS#1 v1.5, RSA-OEAP, and RSASVE, meaning essentially any scenario wherein a device uses classic RSA to establish secure channels is fair game.
Particularly concerning is that SCADA and protection relay networks, especially those in legacy or semi-connected configurations, often do not benefit from aggressive patch management or cutting-edge security monitoring. Such an environment provides fertile ground for attackers equipped with the patience and knowledge to exploit timing leaks.
Patch Availability:
For later 2.2.x versions of the Relion 670 and 650 series, as well as the SAM600-IO, users are instructed to update to specific patched versions (e.g., 2.2.2.6, 2.2.3.7, 2.2.4.4, and 2.2.5.6 or later). Direct downloads and update instructions are available through official Hitachi Energy channels.
General Mitigations:
Where patching is not possible—whether due to operational constraints, unsupported legacy hardware, or custom deployments—Hitachi Energy and cybersecurity authorities advise taking the following steps:
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has amplified vendor guidance, strongly encouraging organizations to conduct risk assessments before deploying mitigations, rigorously applying Defense-in-Depth principles. Resources such as the Defense-in-Depth Strategies guide (PDF) and CISA’s suite of best practice briefs are recommended reading for all involved in industrial cybersecurity.
Hitachi Energy’s prompt coordination with CISA and fast-tracked advisories represent a model response to industrial vulnerabilities. The transparency shown, including clear version-specific patching and mitigation advice, is a noteworthy strength. Where patches are available, the steps are actionable and systematically reduce the attack surface.
Collaborative Ecosystem:
The cooperation between the vendor, global regulators, and the open security community (as evidenced by CVE assignments and clear technical documentation) underpins sound modern risk management. This network of trust and knowledge sharing contrasts favorably with the opacity that has plagued some sectors in the past.
Awareness and Sector-Specific Guidance:
CISA’s attention to sector-specific realities—such as the impracticality of frequent patches in critical infrastructure—ensures the advice is pragmatic. Recommendations on network zoning, internal threat containment, and the minimization of human error offer organizations a multi-layered defense architecture, even when technical patching lags behind.
Not all operational devices can be swiftly updated, especially when operational schedules or custom integrations prevent downtime. Where patching is impossible, reliance on perimeter defenses becomes a double-edged sword: though helpful, they can engender a false sense of security, especially against sophisticated threat actors with knowledge of network topologies.
Complexity of Attack Not a Guarantee of Safety:
Though the Bleichenbacher-style attack requires a high volume of probes and precise timing measurements—a circumstance less likely in heavily firewalled or air-gapped environments—organizations should not underestimate the ingenuity or resources threat actors might deploy. Cloud resources, AI-driven attack tools, and supply-chain intrusions have repeatedly turned the theoretical into reality.
Evolving Attack Surface:
As industrial networks incrementally modernize and edge devices evolve to support more standardized protocols and remote management tools, the risk of latent cryptographic vulnerabilities only grows. Device manufacturers, operators, and even policymakers need to build “secure by design” approaches into the next generation of industrial control equipment.
Global Risk Profile:
With Hitachi Energy headquartered in Japan but selling and deploying globally, this vulnerability has ramifications far beyond any single market or regulatory regime. That many critical networks still struggle with patch governance means an exploit, should one ever be made widely available online, could propagate with devastating speed.
Ultimately, the combination of technical patching, layered defense, and organizational rigor provides the most resilient path forward. While the complexity of Bleichenbacher-style attacks may seem arcane, recent history assures us that once disclosed, attackers will attempt to weaponize even the most sophisticated vulnerabilities. Only an informed, proactive, and collaborative approach can keep critical energy systems secure in an era increasingly defined by cyber risk.
Source: CISA Hitachi Energy Relion 670, 650, SAM600-IO Series | CISA
The Vulnerability: Observable Discrepancy in OpenSSL RSA Implementation
A vulnerability referred to as an “Observable Discrepancy” (CWE-203) forms the basis of this security concern. As detailed in CVE-2022-4304, the affected Hitachi Energy devices employ an OpenSSL RSA decryption implementation susceptible to a classic timing-based side-channel attack. When exploited, this flaw can potentially allow an attacker to recover plaintext transmitted across a network—effectively enabling the decryption of sensitive data in transit and opening doors to a host of further intrusions.The vulnerability earned a CVSS v4 base score of 8.2, indicative of its high impact albeit somewhat mitigated by a high attack complexity. Notably, earlier assessments under the CVSS v3 standard scored the vulnerability at a lower 5.9, reflecting evolving risk assessment methodologies. Critically, this flaw is remotely exploitable; no physical access or user interaction is required, dramatically raising the stakes for utilities and industrial organizations deploying these systems.
Which Products Are Affected?
Hitachi Energy has acknowledged vulnerability across several firmware versions in the Relion 670 and 650 control and protection devices, as well as various SAM600-IO series models. Specifically affected versions span:- Relion 670: 2.2.0, 2.2.1, and a variety of versions between 2.2.2.0 and 2.2.5.5
- Relion 650: 2.2.0, 2.2.1, plus versions 2.2.4.0 through 2.2.5.5
- SAM600-IO: 2.2.1 and versions from 2.2.5.0 up to (but excluding) 2.2.5.5
Understanding the Risk: Unpacking the Attack Vector
The underlying mechanics stem from a Bleichenbacher-style attack—a variant of padding oracle attacks that exploit subtle timing discrepancies or “side channels” in cryptographic operations. Put simply, when a vulnerable device receives encrypted messages, the time it takes to decrypt and respond can leak minute clues about the decryption process. Over a very large number of probes, an attacker—even without credentials—could amass enough subtle differences in response times to piece together the leaked key material and decrypt intercepted traffic.While the attack requires a sophisticated understanding of cryptographic principles and a substantial volume of traffic to perform successfully, history has repeatedly shown that such theoretical risks become practical with increasingly automated attack toolsets and readily available cloud computing resources. Additionally, as OpenSSL’s RSA implementation underpins not just TLS-secured device management but potentially other secure channels within these devices, the broader ramifications are serious.
Sector-wide Impact: Why This Matters
The gravity of this vulnerability isn’t limited to single installations. Hitachi Energy’s Relion and SAM600-IO modules are embedded in the operational fabric of the world’s power grids, substations, and critical automation networks. These devices underpin Supervisory Control and Data Acquisition (SCADA) systems and protection relays—meaning they aren’t just managing data, they’re controlling the flow of electricity across entire countries and continents.Breaches of such systems could expose power grid control networks to eavesdropping, data manipulation, or even direct disruption. Recent history—including incidents like the 2015 Ukrainian power grid cyberattack—has demonstrated the tangible threat posed by cyberattacks on industrial energy systems. It cannot be overstated: vulnerabilities in these devices are not abstractions; they have the potential for real-world blackouts, economic disruptions, or worse.
Detailed Technical Analysis: Prelude to the Bleichenbacher Attack
OpenSSL, a cornerstone of cryptographic operations worldwide, had previously been criticized for inconsistent handling of RSA padding in its PKCS#1 v1.5 and other modes. Attackers exploit side-channel clues—small differences in error messages or, in this case, decryption response times—to iteratively whittle down possible values until the underlying plaintext, like a session key, is exposed. Once an attacker has the session key, the entire prior (and potentially ongoing) secure conversation becomes plaintext to them.The cited vulnerability affects all RSA padding modes used by OpenSSL in the affected versions. This includes PKCS#1 v1.5, RSA-OEAP, and RSASVE, meaning essentially any scenario wherein a device uses classic RSA to establish secure channels is fair game.
Particularly concerning is that SCADA and protection relay networks, especially those in legacy or semi-connected configurations, often do not benefit from aggressive patch management or cutting-edge security monitoring. Such an environment provides fertile ground for attackers equipped with the patience and knowledge to exploit timing leaks.
Mitigation and Remediation: Guidance and Best Practices
Vendor Actions
Hitachi Energy’s advisory, catalogued under 8DBD000157, recommends a dual approach to mitigation: some device versions receive direct firmware patches, while others require general mitigation strategies.Patch Availability:
For later 2.2.x versions of the Relion 670 and 650 series, as well as the SAM600-IO, users are instructed to update to specific patched versions (e.g., 2.2.2.6, 2.2.3.7, 2.2.4.4, and 2.2.5.6 or later). Direct downloads and update instructions are available through official Hitachi Energy channels.
General Mitigations:
Where patching is not possible—whether due to operational constraints, unsupported legacy hardware, or custom deployments—Hitachi Energy and cybersecurity authorities advise taking the following steps:
- Isolate vulnerable systems by configuring firewalls to limit all external access to control networks.
- Enforce strict physical security, preventing unauthorized personnel from accessing equipment.
- Prohibit direct internet connectivity to control system devices, instead relying on segmented, firewalled internal networks.
- Vigilantly scan all removable storage and portable computers for malware before allowing them access to control networks.
- Mandate strong password policies, minimize inter-network trust, and log all remote access attempts.
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has amplified vendor guidance, strongly encouraging organizations to conduct risk assessments before deploying mitigations, rigorously applying Defense-in-Depth principles. Resources such as the Defense-in-Depth Strategies guide (PDF) and CISA’s suite of best practice briefs are recommended reading for all involved in industrial cybersecurity.
Critical Analysis: Strengths, Risks, and Broader Lessons
Strengths
Rapid Disclosure and Patch Availability:Hitachi Energy’s prompt coordination with CISA and fast-tracked advisories represent a model response to industrial vulnerabilities. The transparency shown, including clear version-specific patching and mitigation advice, is a noteworthy strength. Where patches are available, the steps are actionable and systematically reduce the attack surface.
Collaborative Ecosystem:
The cooperation between the vendor, global regulators, and the open security community (as evidenced by CVE assignments and clear technical documentation) underpins sound modern risk management. This network of trust and knowledge sharing contrasts favorably with the opacity that has plagued some sectors in the past.
Awareness and Sector-Specific Guidance:
CISA’s attention to sector-specific realities—such as the impracticality of frequent patches in critical infrastructure—ensures the advice is pragmatic. Recommendations on network zoning, internal threat containment, and the minimization of human error offer organizations a multi-layered defense architecture, even when technical patching lags behind.
Risks and Limitations
Residual Threats in Unpatchable or Legacy Devices:Not all operational devices can be swiftly updated, especially when operational schedules or custom integrations prevent downtime. Where patching is impossible, reliance on perimeter defenses becomes a double-edged sword: though helpful, they can engender a false sense of security, especially against sophisticated threat actors with knowledge of network topologies.
Complexity of Attack Not a Guarantee of Safety:
Though the Bleichenbacher-style attack requires a high volume of probes and precise timing measurements—a circumstance less likely in heavily firewalled or air-gapped environments—organizations should not underestimate the ingenuity or resources threat actors might deploy. Cloud resources, AI-driven attack tools, and supply-chain intrusions have repeatedly turned the theoretical into reality.
Evolving Attack Surface:
As industrial networks incrementally modernize and edge devices evolve to support more standardized protocols and remote management tools, the risk of latent cryptographic vulnerabilities only grows. Device manufacturers, operators, and even policymakers need to build “secure by design” approaches into the next generation of industrial control equipment.
Global Risk Profile:
With Hitachi Energy headquartered in Japan but selling and deploying globally, this vulnerability has ramifications far beyond any single market or regulatory regime. That many critical networks still struggle with patch governance means an exploit, should one ever be made widely available online, could propagate with devastating speed.
Moving Forward: Recommendations for Security-Conscious Operators
For organizations deploying Hitachi Energy Relion 670, 650, or SAM600-IO series devices, several key takeaways demand urgent attention:- Check Your Versions:
Determine if your deployments run affected software releases. This is a necessary first step and should trigger immediate investigation if outdated firmware is found. - Patch Where Possible:
If a patch is available for your platform, prioritize internal processes for tested, staged deployment. Maintain a record of firmware status for compliance and audit purposes. - Strengthen Segmentation:
Adopt a zero-trust model for network segments housing industrial control systems. Tighten rules on lateral movement and scrutinize network traffic for unusual access patterns. - Enhance Visibility and Monitoring:
Invest in industrial intrusion detection/prevention systems (IDS/IPS) capable of detecting abnormal traffic and potential reconnaissance attempts against SCADA and protection relay networks. - Cultivate a Strong Security Culture:
Continually train operations and engineering staff on physical and cyber security best practices. Encourage a culture of vigilance—not just compliance—to help detect and report anomalous events early. - Participate in Information Sharing Efforts:
Join industry ISACs or collaborate with regulators such as CISA to stay current with the threat landscape and mitigation techniques.
Conclusion: A Cautionary Tale for Industrial Cybersecurity
The discovery and responsible disclosure of the OpenSSL RSA side channel vulnerability within prominent Hitachi Energy products should serve as a wakeup call to the wider industrial and critical infrastructure community. As operational technology networks become more interconnected and complex, the smallest cryptographic design flaw can ripple outwards to global consequence.Ultimately, the combination of technical patching, layered defense, and organizational rigor provides the most resilient path forward. While the complexity of Bleichenbacher-style attacks may seem arcane, recent history assures us that once disclosed, attackers will attempt to weaponize even the most sophisticated vulnerabilities. Only an informed, proactive, and collaborative approach can keep critical energy systems secure in an era increasingly defined by cyber risk.
Source: CISA Hitachi Energy Relion 670, 650, SAM600-IO Series | CISA
