# Hitachi Energy Relion RSA timing side-channel in OpenSSL

Published: 2026-03-17 · Severity: elevated · Sectors: energy, infrastructure
Canonical: https://vorant.io/reports/08550198-033d-5f5d-a964-0b382559cba6/hitachi-energy-relion-rsa-timing-side-channel-in-openssl

> CVE-2022-4304 timing attack in OpenSSL affects Hitachi Energy Relion 670, 650, SAM600-IO; decrypt TLS traffic via RSA decryption timing.

Hitachi Energy has published a security advisory addressing CVE-2022-4304, a timing-based side-channel vulnerability in the OpenSSL RSA decryption implementation affecting multiple versions of the Relion 670, 650, and SAM600-IO series. This is a Bleichenbacher-style attack that exploits timing differences in RSA decryption across all padding modes (PKCS#1 v1.5, RSA-OEAP, RSA-SVE). An attacker with network access to observed TLS connections can send a large number of trial decryption messages to the affected device, record processing times, and use the timing patterns to recover the pre-master secret, allowing decryption of previously captured TLS application data.

The vulnerability affects Relion 670/650 series version 2.2.0 (all revisions), versions 2.2.1 through 2.2.1.8, 2.2.2 through 2.2.2.5, 2.2.3 through 2.2.3.6, 2.2.4 through 2.2.4.3, and Relion 670/650/SAM600-IO series version 2.2.5 through 2.2.5.5. Hitachi Energy has released patched versions (2.2.1.9, 2.2.2.6, 2.2.3.7, 2.2.4.4, 2.2.5.6 and later) that remediate the issue.

Defenders managing these critical infrastructure protection devices should prioritize updating to the latest patched versions, isolate affected systems from direct internet exposure, restrict network access to TLS endpoints, and implement monitoring for anomalous connection patterns or timing-based scanning attempts.

## Mentioned in this report

- Vulnerabilities: CVE-2022-4304

Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-25-160-02

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