ICS Security Network Architecture and Protocols 2

Question 1

Which ICS protocol transmits data in plaintext and is therefore considered inherently insecure?

Accepted Answer

Modbus TCP

Answer

Modbus TCP lacks built-in authentication or encryption, transmitting all data in plaintext.

Question 2

What is the primary purpose of a demilitarized zone (DMZ) in an ICS network architecture?

Accepted Answer

To host historian servers accessible from both OT and IT networks

Answer

An ICS DMZ hosts shared services like historians so neither the IT nor OT network directly communicates with the other.

Question 3

In the Purdue Reference Model, which level hosts supervisory control functions such as SCADA servers and HMIs?

Accepted Answer

Level 2

Answer

Level 2 of the Purdue Model is the Supervisory Control level, housing SCADA systems and HMIs.

Question 4

A defense-in-depth strategy for ICS networks primarily relies on which concept?

Accepted Answer

Layered security controls across multiple zones

Answer

Defense-in-depth applies multiple overlapping security controls so that failure of one layer does not compromise the entire system.

Question 5

Which protocol is commonly used for secure remote access tunneling into ICS environments?

Accepted Answer

IPsec VPN

Answer

IPsec VPN provides encrypted, authenticated tunnels for secure remote access into ICS environments.

(ICS) Industrial Control Systems Security Certification Practice Test