Threat Modeling ISE Practice Questions (Page 10)

Questions 46–50

1. 46application · easy

   An IoT security team has identified four threats to a fleet of smart meters. They need to prioritize remediation based on risk. Threat A: remote code execution with a likelihood of 4 and impact of 5. Threat B: denial of service with a likelihood of 5 and impact of 3. Threat C: data tampering with a likelihood of 3 and impact of 4. Threat D: physical tampering with a likelihood of 2 and impact of 5. Using a simple risk score of likelihood × impact, which threat should be addressed first?

   • AThreat B (denial of service)
   • BThreat D (physical tampering)
   • CThreat C (data tampering)
   • DThreat A (remote code execution)
   Reveal Solution Discussion Select an answer first
2. 47foundation · easy

   What is the primary purpose of threat modeling in the context of IoT systems?

   • ATo guarantee that no security vulnerabilities exist in the IoT system after deployment
   • BTo document the system architecture and data flows for regulatory compliance only
   • CTo identify and prioritize potential security threats so that mitigation efforts focus on the most significant risks
   • DTo replace the need for penetration testing and vulnerability scanning in the development lifecycle
   Reveal Solution Discussion Select an answer first
4. 48foundation · easy

   Which statement best describes the role of threat modeling in the IoT system development lifecycle?

   • AIt is performed only after a security incident to understand how the attack occurred
   • BIt is an ongoing process that helps identify and prioritize threats early, guiding design and mitigation decisions
   • CIt is a one-time activity conducted at the end of development before deployment
   • DIt is primarily a documentation exercise that has little impact on actual security decisions
   Reveal Solution Discussion Select an answer first
5. 49expert · hard

   A team is threat modeling a smart irrigation system. They have created a data flow diagram and are applying STRIDE. They identify a threat where an attacker can replay a legitimate command to open a valve, causing water waste. Which STRIDE category does this threat belong to, and what is the most effective mitigation?

   • ARepudiation; mitigate by logging all commands with timestamps.
   • BSpoofing; mitigate by using mutual authentication between the controller and the valve.
   • CTampering; mitigate by using a message authentication code (MAC) on each command.
   • DSpoofing; mitigate by including a nonce or timestamp in each command and verifying it on the receiver.
   Reveal Solution Discussion Select an answer first
6. 50application · medium

   A company manufactures smart locks that use a mobile app for unlocking. Threat modeling identified that the BLE communication between the phone and lock lacks encryption, allowing an attacker to replay unlock commands. The team must choose a mitigation. Which mitigation is most effective in directly addressing the replay attack?

   • AIncrease the BLE transmission power to improve range.
   • BRequire the user to re-enter a PIN every time they unlock the lock.
   • CImplement a rolling code or timestamped challenge-response authentication for BLE commands.
   • DAdd a physical key override as a backup unlocking method.
   Reveal Solution Discussion Select an answer first