In this lesson, we'll explore the Purdue Model
for industrial control systems (ICS) for short.
This foundational framework is designed
to protect operational technology (OT) environments.
Established as part
of the Purdue Enterprise Reference Architecture,
this model helps define network segmentation
and industrial settings to isolate and protect OT systems
from potential cyber threats, including malware attacks.
Originally developed
to support computer-integrated manufacturing,
the Purdue Model organizes network architecture
with a focus on OT security.
It ensures that data flows follow a hierarchical structure
that supports both security and smooth operations.
This model is especially useful in environments
where edge computing and direct-to-cloud connectivity
are common, helping to maintain critical protections
even though the traditional network boundaries have changed.
The Purdue Model is divided into six distinct levels
or zones, each designed to handle specific types of data
and system interactions.
Starting at the top, we have Level 5,
known as External/Vendor Support/Cloud Access,
is part of the Enterprise Security Zone.
It features strong IT controls that focus on risk reduction
and managing interactions with external vendors
and cloud services.
This level supports industrial operations
that rely on external partnerships and cloud technologies.
Level 4,
the Business Logistics Systems/Enterprise IT level,
also has strong IT controls.
It covers corporate IT operations,
including enterprise resource planning systems.
These systems manage crucial business functions
like production scheduling, material use,
shipping, and inventory management,
ensuring smooth logistics operations
across the entire enterprise.
Next, we have level 3.5,
which is that Demilitarized Zone (DMZ).
This buffer zone hosts security measures like firewalls
and proxies to control the exchange of data
between IT and OT systems,
preventing potential threats from spreading.
Level 3, the Manufacturing Operations Systems Zone,
hosts operations management systems
such as Manufacturing Execution Systems.
These systems direct real-time manufacturing processes
and include historical records
that store critical operational data for analysis,
ensuring continuous monitoring
and optimization based on accurate data.
Level 2, the Control Systems Zone, includes devices
like the Supervisory Control and Data Acquisition
(SCADA) systems, which monitor
and actually control physical processes.
Level 1, the Intelligent Devices Zone,
includes Programmable Logic Controllers (PLCs),
that manage operations based on real-time data
from sensors in the Physical Process Zone.
And level 0, the Physical Process Zone,
is where the actual manufacturing process occurs.
It includes sensors and actuators that directly interact
with the manufacturing operations.
Now, the relevance of the Purdue Model remains very high
despite changes in industrial networking,
and merging of IT and OT,
especially with the Industrial Internet of Things.
While direct-to-cloud flow from level 0 devices
challenges traditional models,
the Purdue Model still provides a solid framework
for segmenting and protecting networks.
The model's clear zones and strict controls at each level
help prevent unauthorized access and manage cyber risk.
Even with new technologies and methods emerging,
the Purdue Model adapts,
continuing to offer a valuable blueprint
for securing industrial control systems.
So remember, the Purdue Model is crucial
for ensuring operational integrity
and security in industrial settings.
It offers great flexibility in handling traditional
and new challenges like the integration
of the Industrial Internet of Things
and traditional cloud technologies.
It provides a structured approach to network segmentation,
which is important for protecting against cyber threats
and managing complex data flows.