Modbus / RS485 Security Model

Status: DRAFT

The inverter Modbus RTU interface is considered a legacy local control interface without authentication, authorization or encryption.

Security rule

The backend MUST NOT have unrestricted raw register-write capability.

Required gateway controls

• supported-command allowlist
• supported-inverter allowlist
• writable-register allowlist
• accepted value/range validation
• timeout/retry limits
• serialized Modbus access
• command idempotency where possible
• audit log of state-changing writes

Example

Allowed:

SetOperatingMode(BUY)

Not allowed as a public cloud command:

WriteRegister(address=0x024E, value=1234)