ICS/SCADA Security Model ICSSCADA Practice Questions (Page 6)

Questions 26–30

1. 26expert · hard

   A large utility is upgrading its legacy SCADA system. The current architecture has the HMI, engineering workstation, and SCADA server all at Level 2, but they are on separate VLANs. The new design proposes moving the SCADA server to Level 3 to improve security. The operations team is concerned about latency and reliability. What is the most appropriate decision?

   • AMove the SCADA server to Level 3 as proposed, accepting the potential latency increase.
   • BPlace the SCADA server in the same zone as the HMI to simplify management and reduce complexity.
   • CKeep the SCADA server at Level 2 but ensure it is in a separate zone with strict conduits to other Level 2 devices.
   • DRemove the SCADA server from the network and use a cloud-based SCADA solution.
   Reveal Solution Discussion Select an answer first
2. 27application · medium

   A power generation facility is designing its network. The team needs to allow the engineering workstation (Level 2) to communicate with the PLC (Level 1) for programming. According to the zone and conduit model, how should this communication be handled?

   • ABlock all communication between the engineering workstation and the PLC to ensure security.
   • BUse a direct cable connection between the engineering workstation and the PLC, bypassing the network.
   • CCreate a conduit between the Level 2 zone and the Level 1 zone, allowing only necessary protocols.
   • DPlace the engineering workstation and the PLC in the same zone to simplify communication.
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4. 28application · medium

   A mining company is designing a network for a new site. The design includes a control room with HMIs, a server room with a historian, and a remote crusher with a PLC. The PLC communicates with the HMI over a fiber link. The security team needs to define the zones and conduits. Which of the following is the most accurate representation?

   • AThe fiber link is a zone, and the control room, server room, and crusher are conduits.
   • BThe control room, server room, and crusher are all in the same zone because they are part of the same system.
   • CThe control room and server room are in one zone, the crusher is in another zone, and the fiber link is a conduit.
   • DThe HMI and PLC are in the same zone, and the fiber link is a separate zone.
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5. 29application · easy

   A wastewater treatment plant has a Level 2 HMI that is accessed by operators from the control room. The security team wants to add a control that specifically prevents unauthorized changes to the HMI's configuration. Which control is most appropriate?

   • ADeploy an IDS on the HMI network segment.
   • BAdd a firewall between the HMI and the PLC.
   • CIncrease the logging level on the HMI.
   • DImplement role-based access control (RBAC) on the HMI so only authorized operators can modify configuration settings.
   Reveal Solution Discussion Select an answer first
6. 30application · medium

   A manufacturing plant has a Level 3 historian that is accessed by engineers from the corporate network (Level 4). The security team needs to implement a control that specifically protects the historian from unauthorized access while still allowing legitimate engineering access. Which control is most appropriate?

   • APlace the historian on the corporate network so engineers can access it without crossing the boundary.
   • BInstall a second historian on the corporate network and replicate data from the Level 3 historian.
   • CDisable the historian's network interface and require engineers to physically access the console.
   • DConfigure a firewall rule on the conduit between Level 3 and Level 4 that only allows traffic from the engineering subnet to the historian on the required port.
   Reveal Solution Discussion Select an answer first