ICS Deep Packet Inspection (DPI)

Industrial/ICS 🏭 Difficulty: premium

Definition

ICS Deep Packet Inspection decodes industrial protocols at the application layer to validate semantics, enforce command policy, and detect unsafe or unauthorized operations—far beyond simple port/IP filtering.

Examples

  • An inline sensor blocks a Modbus write command to a PLC because the function code and register range aren’t on the approved allowlist for that device.
  • A passive sensor flags an IEC-104 control command from an unexpected source and outside the normal polling window.

Discover 🔎

Generic firewalls and IDS see ports and IPs; ICS DPI understands the language of the plant. By parsing protocols like Modbus, DNP3, IEC 60870-5-104, IEC 61850 MMS/GOOSE, EtherNet/IP (CIP), PROFINET, OPC UA, BACnet, and Siemens S7, DPI can tell reads from writes, validate command parameters, and enforce policy tied to the process. Done well, DPI provides high-fidelity detection and precise control with minimal disruption to deterministic traffic.

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