4.1 Explain the importance of basic network security concepts
Network Segmentation Enforcement
📘CompTIA Network+ (N10-009)
1. What is SCADA, ICS, and OT?
To understand network segmentation in these environments, first, we need to know the systems involved:
- SCADA (Supervisory Control and Data Acquisition):
A system used to monitor and control industrial processes. It collects data from sensors and sends commands to devices to control machinery or processes. - ICS (Industrial Control Systems):
The broader category that includes SCADA and other control systems like DCS (Distributed Control Systems). ICS manages industrial operations, like factory machines, power plants, or manufacturing lines. - OT (Operational Technology):
Hardware and software that monitor and control physical devices, processes, and events in industrial environments. OT focuses on “doing” things in the real world, like controlling valves, motors, or sensors, unlike IT which focuses on data.
Key Difference: IT systems deal with data and communication; OT systems deal with controlling physical processes.
2. Why Network Segmentation is Important for SCADA/ICS/OT
Network segmentation is dividing a network into smaller, isolated parts to improve security and manage traffic efficiently.
For SCADA/ICS/OT:
- Protect Critical Systems:
These systems often control essential industrial processes. If an attacker gains access, it could disrupt operations or cause physical damage. Segmentation isolates these systems from general IT networks. - Limit Attack Spread:
If a malware or ransomware infects one part of the network, segmentation prevents it from spreading to the SCADA/ICS/OT systems. - Compliance Requirements:
Many industrial and critical infrastructure environments must follow security regulations. Segmentation is often a required security control. - Minimize Human Error Impact:
Operators or IT staff working on IT systems cannot accidentally access sensitive OT systems if the network is segmented properly.
3. How Network Segmentation is Implemented in SCADA/ICS/OT
Here’s how segmentation works in practice:
a. Physical Segmentation
- Separate physical network cables or switches for IT and OT networks.
- Example: SCADA devices connect to an OT-only switch and not to the IT network.
b. Logical Segmentation
- Use VLANs (Virtual Local Area Networks) to separate traffic within the same physical network.
- Example: One VLAN for SCADA devices, another VLAN for the IT office network, and rules in the router/firewall prevent cross-VLAN traffic unless necessary.
c. Firewalls and Access Control
- Firewalls control which devices or applications can communicate across network segments.
- Example: Only specific IT servers can communicate with the SCADA system for maintenance; everything else is blocked.
d. Demilitarized Zone (DMZ)
- A DMZ acts as a buffer zone between IT and OT networks.
- Example: If an IT application needs to collect data from SCADA, it goes through the DMZ, which monitors and controls the data flow.
e. Network Monitoring
- Monitor network traffic to detect unusual patterns.
- Example: If a device in the OT network suddenly tries to access external websites, alerts are triggered.
4. Benefits of Network Segmentation in SCADA/ICS/OT
| Benefit | Explanation |
|---|---|
| Security | Limits malware spread and prevents unauthorized access. |
| Operational Safety | Reduces risk of disruptions in industrial processes. |
| Compliance | Helps meet standards for industrial security (like IEC 62443). |
| Performance | Reduces network congestion and improves response times in critical systems. |
5. Exam Tips for AZ-104
- Remember the Goal: Segmentation separates networks to protect critical systems and limit attacks.
- Know the Methods: Physical separation, VLANs, firewalls, DMZ, and monitoring.
- SCADA/ICS/OT Focus: Always highlight that OT systems control real processes, so security is about protecting both data and operations.
- Example You Can Use:
- IT network: Office computers, email, file servers.
- OT network: SCADA controllers, sensors, and actuators.
Segmentation ensures that if IT network is compromised, OT network stays safe.
✅ Key Takeaway:
Network segmentation in SCADA/ICS/OT is about safely isolating critical industrial control systems from IT networks to prevent attacks, ensure operational continuity, and maintain compliance.
