Hitachi Energy AFS, AFR and AFF Series

An attacker with network access to the RADIUS authentication mechanism could bypass or compromise authentication, potentially gaining unauthorized control of the protective relay to modify settings, disable protection schemes, or disrupt power grid operations.

Energy sector organizations operating Hitachi Energy protective relays (AFS, AFR, AFF series) used in power generation, transmission, and distribution equipment. These devices control protection schemes for critical power infrastructure. Any organization using these models in substations, power plants, or distribution networks is affected, as no patches are available from the vendor.

An attacker on the network segment containing the AFS/AFR/AFF device must craft malicious RADIUS authentication messages that exploit the missing message authenticator validation. By sending crafted RADIUS responses, the attacker could forge authentication packets to bypass or spoof RADIUS server identity, compromising the integrity of the authentication exchange and potentially gaining unauthorized access to the device's configuration and control interfaces.