Selecting and Applying Controls to Mitigate Risk ICSSCADA Practice Questions (Page 9)

Questions 41–45

1. 41application · medium

   A mining company operates a distributed control system (DCS) that runs on a legacy operating system no longer supported by the vendor. The system is critical and cannot be upgraded in the near term. Which control is most appropriate to mitigate the risk of unpatched vulnerabilities?

   • AApply all available patches from the vendor, even if they are not tested.
   • BReplace the DCS immediately with a modern system.
   • CSegment the DCS network from the corporate network and restrict all external access.
   • DDisconnect the DCS from all networks and use manual controls.
   Reveal Solution Discussion Select an answer first
2. 42application · medium

   A water treatment facility has a flat network where operators, engineers, and the SCADA server all share the same subnet. A recent risk assessment identified that a compromised operator workstation could directly reach the PLCs that control chemical dosing. Management wants to reduce this risk without replacing the existing PLCs. What is the most effective control to implement?

   • AAdd a second network interface card to each PLC and connect it to a separate management network.
   • BChange all PLC passwords to a longer, more complex shared password.
   • CInstall antivirus software on all operator workstations and enable automatic signature updates.
   • DDeploy a firewall between the operator subnet and the PLC subnet, allowing only the SCADA server to initiate connections to the PLCs.
   Reveal Solution Discussion Select an answer first
4. 43application · medium

   A water utility has a disaster recovery plan that includes restoring the SCADA system from backups. During a recent test, the team discovered that the backups were corrupted and could not be restored. Which control should be added to the plan to prevent this from happening again?

   • AIncrease the frequency of backups to every hour.
   • BStore backups in the same location as the SCADA servers for faster access.
   • CAssign a single administrator to manage all backup and recovery tasks.
   • DPerform regular backup restoration tests and verify the integrity of backups after each backup job.
   Reveal Solution Discussion Select an answer first
5. 44foundation · easy

   Which control is essential for rapid restoration of an ICS after a ransomware attack?

   • ARegularly tested backups of critical system configurations and data
   • BNetwork segmentation
   • CA strong password policy
   • DAn intrusion prevention system (IPS)
   Reveal Solution Discussion Select an answer first
6. 45application · medium

   A wastewater plant has a SCADA network that includes a historian, an HMI server, and several PLCs. The plant wants to allow remote engineers to access the HMI for monitoring, but they should not be able to modify any setpoints. Which zoning and access control approach is most appropriate?

   • AAllow remote engineers to connect directly to the HMI server through a VPN without additional authentication.
   • BGive remote engineers full access to the historian so they can monitor historical data.
   • CPlace the HMI server in a DMZ and require remote engineers to authenticate with read-only credentials.
   • DPlace the PLCs directly in the DMZ and allow remote engineers to connect to them.
   Reveal Solution Discussion Select an answer first