Objective 6.2 Implement Countermeasures Used to Provide Secure Software/firmware. CERTIFIED-IOT-SECURITY-PRACTITIONER Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   What does measured boot record during the boot process?

   • AThe number of times the device has been booted
   • BThe time taken to boot the device
   • CThe temperature of the CPU during boot
   • DThe integrity measurements (hashes) of each boot component
   Reveal Solution Discussion Select an answer first
2. 17expert · hard

   A manufacturer's signing key for firmware updates is compromised. The manufacturer needs to revoke trust in the old key and issue new updates signed with a new key. The devices in the field have the old public key stored in their root of trust. What is the most effective way to update the devices to trust the new key?

   • ASend the new public key to devices over a plain HTTP connection and have them accept it.
   • BUse the new key to sign updates and send them to devices, expecting them to accept the new key automatically.
   • CIssue a signed update that contains the new public key and is signed with the old key, and have devices verify it before updating their trust store.
   • DRequire devices to be physically returned to the manufacturer for key replacement.
   Reveal Solution Discussion Select an answer first
4. 18application · medium

   A security architect is designing a new IoT device and wants to establish a chain of trust starting from an immutable hardware component. The device must verify the bootloader before it executes and then verify the OS kernel. Which component serves as the root of trust in this design?

   • AThe OS kernel, because it is the first software component to run and can verify all subsequent stages.
   • BA hardware-based secure element or TPM with a burned-in public key, because it is immutable and can verify the bootloader.
   • CThe bootloader, because it is the first code executed and can verify the OS kernel.
   • DThe update server's certificate, because it provides the trust anchor for all software on the device.
   Reveal Solution Discussion Select an answer first
5. 19application · medium

   A medical device manufacturer must update device firmware remotely. The update process must prevent an attacker from intercepting the update and modifying it in transit, and also prevent the installation of updates from unauthorized sources. Which two controls, when used together, best address these requirements?

   • AUse a strong encryption algorithm for the update file and rely on the secrecy of the decryption key.
   • BUse a VPN for the update download and rely on the VPN's authentication for source verification.
   • CUse a checksum published on the manufacturer's website and compare it on the device.
   • DUse TLS for the update download and verify the update's digital signature on the device.
   Reveal Solution Discussion Select an answer first
6. 20application · medium

   A company needs to update the certificates used for TLS on thousands of IoT devices. The devices support remote update of certificates. What is the most secure way to perform this update?

   • AEmbed the new certificates in the next firmware update and install them without additional checks.
   • BHave each device download the certificates from a public website without any verification.
   • CSend the new certificates in plain text over the network and rely on the device to accept them.
   • DPush the new certificates to the devices over a secure channel and verify their authenticity before installation.
   Reveal Solution Discussion Select an answer first