A security architect is designing an endpoint security solution for a critical industrial control system (ICS) environment. Due to the sensitive nature and strict operational requirements, traditional active agents cannot be installed on all devices, and network segmentation must be extremely granular. Which approach would best integrate Zero Trust principles into this challenging environment?
- AEnforcing strict firewall rules only at the perimeter of the ICS network.
- BImplementing network micro-segmentation with policy enforcement at the network edge, combined with passive device profiling.
- CDeploying a full EDR solution on all ICS endpoints for continuous monitoring.
- DUtilizing cloud-based security analytics platforms to detect anomalies across the ICS network.
Show answer & explanationAnswer & explanation
Correct answer: B. Implementing network micro-segmentation with policy enforcement at the network edge, combined with passive device profiling.
In ICS environments, active agents are often problematic. Implementing network micro-segmentation, with policy enforcement at the network edge (e.g., using switches or firewalls to apply policies based on passively identified devices), aligns with Zero Trust's 'Never Trust, Always Verify' and 'Least Privilege' principles without requiring endpoint agents.
Why the other options are wrong
- A. Enforcing firewall rules only at the perimeter provides coarse-grained security and is insufficient for Zero Trust's granular, internal segmentation requirements, especially for lateral movement threats.
- C. Deploying full EDR agents on all ICS endpoints is often not feasible due to compatibility, performance, and certification issues in sensitive operational technology (OT) environments.
- D. Cloud-based analytics might be challenging due to air-gapped or highly restricted ICS network connectivity and data sovereignty concerns.
Zero Trust for ICS (Agentless)
Applying Zero Trust principles to Industrial Control Systems (ICS) often involves agentless solutions like network micro-segmentation and passive device profiling due to the constraints of OT environments.
- Avoids active agents on sensitive ICS devices.
- Achieves granular control through network-based enforcement.
- Passive profiling identifies devices and their intended communications.
- Critical for preventing lateral movement and unauthorized access in OT.
Memory trick: ICS needs 'Segmented Safety' without 'Agent Aggravation'.