ICS Access Control & Perimeter Security 2

Question 1

Which ICS-specific challenge makes traditional role-based access control (RBAC) difficult to implement?

Accepted Answer

Many legacy controllers lack authentication capabilities entirely

Answer

Many legacy PLCs and RTUs were designed without authentication mechanisms, making enforcement of RBAC impossible without compensating controls like network segmentation.

Question 2

A unidirectional security gateway (data diode) is best suited for which perimeter security scenario?

Accepted Answer

Transferring historian data from OT to IT without any return path

Answer

Data diodes enforce one-way data flow at the hardware level, making them ideal for replicating OT historian data to the IT network while physically preventing any inbound traffic.

Question 3

In ICS environments, what is the PRIMARY risk of using shared accounts for HMI operator access?

Accepted Answer

Inability to attribute actions to specific individuals during incident investigation

Answer

Shared accounts eliminate individual accountability, making it impossible to determine which operator performed a specific action during a post-incident forensic review.

Question 4

Which NERC CIP standard specifically addresses Electronic Security Perimeters (ESPs) for bulk electric system facilities?

Accepted Answer

CIP-005

Answer

NERC CIP-005 requires identification and protection of Electronic Security Perimeters, including controlling all Electronic Access Points into those perimeters.

Question 5

What distinguishes a DMZ in an ICS architecture from a traditional IT DMZ?

Accepted Answer

ICS DMZs host services like historians and jump servers between OT and IT zones

Answer

An ICS DMZ hosts shared services (historians, remote access jump servers, file transfer zones) that bridge OT and IT networks while preventing direct connectivity between the two zones.

(ICS) Industrial Control Systems Security Certification Practice Test

(ICS) Industrial Control Systems Security Certification Practice Test

ICS Access Control & Perimeter Security 2