Moxa UC-1200A EUVD-2026-36411

Requires invasive physical access to the UC-1200A device: the attacker must open the chassis and physically attach SPI bus probing equipment (logic analyzer or sniffer) between the SoC and the discrete TPM2 chip, then trigger a boot/unseal cycle to capture the LUKS key in transit. No network access, no credentials, and no user interaction are needed once physical access is obtained, but exploitation is strictly limited to the specific tampered device - there is no remote vector and no impact on downstream/connected systems per the vendor. The condition is the misconfigured TPM2 authorization session in Moxa's embedded Linux firmware on UC-1200A series; devices that do not use TPM-sealed LUKS, or that run a patched firmware with the corrected session attributes, are not exploitable via this path.

Real-world risk is moderate and highly bounded. The CVSS 4.0 score of 7.0 is driven by high VC/VI/VA (full disk compromise) but tempered by AV:P (physical) and the description's emphasis that the attacker must open the device and attach equipment to the SPI bus. There is no KEV listing, no public POC, and no EPSS signal indicating opportunistic mass exploitation - consistent with a hardware-level attack that does not scale. The realistic threat model is targeted: stolen/seized devices, supply-chain interdiction, or insider access in unattended OT/ICS field deployments where UC-1200A controllers are often installed in cabinets without tamper response. For fleets in physically secure facilities the priority is low; for devices deployed in remote substations, vehicles, or kiosks the priority rises sharply because the attack fully defeats LUKS at-rest protection. Note the vendor explicitly states downstream systems are unaffected, so blast radius is per-device.

An attacker gains brief unattended physical access to a deployed UC-1200A - for example a controller in a remote substation cabinet or a stolen unit - opens the chassis, clips a logic analyzer or SPI sniffer onto the bus between the SoC and the TPM2 chip, and power-cycles the device. During the boot-time unseal operation the LUKS key traverses the SPI bus and, because parameter encryption is misconfigured, is captured in plaintext; the attacker then images the storage and unlocks the encrypted volume offline at leisure. No public exploit identified at time of analysis, but the technique mirrors well-known TPM sniffing attacks against BitLocker that have public tooling.