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ISO 27400 Foundation study materials
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ISO 27400 Foundation practice questions

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Question 1Fundamental concepts and principles of IoT security and privacy

In ISO/IEC 27400, which statement best describes the relationship between IoT security and privacy controls?

  1. Privacy is a legal topic outside the scope of the guidance, which addresses only technical security
  2. Privacy controls are optional add-ons that only matter when personal data is stored on a device
  3. Security controls always guarantee privacy compliance without further measures
  4. Security and privacy are interdependent, because weak security can directly cause privacy harm to people affected by the device Correct answer.

Explanation

The guidance treats security and privacy as linked concerns: a compromise of an IoT device can expose or infer information about individuals, so privacy protection depends on adequate security. It also stresses that security alone does not satisfy privacy expectations, which need separate consideration of data minimization and transparency.

Question 2Fundamental concepts and principles of IoT security and privacy

An organization deploys smart sensors in a public building. Which characteristic of IoT environments most directly complicates applying traditional IT security assumptions?

  1. Devices often operate unattended in physical spaces and interact directly with the environment and people Correct answer.
  2. Devices are typically general-purpose computers with full operating systems
  3. Devices always use the same network protocols as enterprise servers
  4. Devices are usually administered interactively by end users every day

Explanation

IoT devices are commonly embedded in the physical world, run unattended, and sense or act on their surroundings, which creates exposure that classic IT assets do not have. This physical coupling and lack of direct supervision are central to the risk picture the guidance describes.

Question 3Fundamental concepts and principles of IoT security and privacy

Which term describes the property that a party interacting with an IoT device can confirm the identity claimed by that device or by the other party?

  1. Availability
  2. Resilience
  3. Authentication Correct answer.
  4. Accountability

Explanation

Authentication is the property of verifying a claimed identity, whether of a device, service, or user. In IoT, mutual authentication between devices and backend services is a foundational control because trust cannot rest on physical proximity alone.

Question 4Fundamental concepts and principles of IoT security and privacy

A manufacturer ships a device with a unique per-device credential rather than a shared default password. Which risk does this practice primarily reduce?

  1. The risk that the device will exceed its power budget in low-power modes
  2. The risk that the device will lose network connectivity during firmware updates
  3. The risk that an attacker can use one known credential to compromise many devices at once Correct answer.
  4. The risk that sensor readings will be inaccurate due to calibration drift

Explanation

Shared or default credentials create a systemic weakness: one discovered secret unlocks an entire device population. Unique per-device credentials limit the blast radius of a single compromise to that device, which is why the guidance addresses credential management and avoiding predictable defaults.

Question 5Fundamental concepts and principles of IoT security and privacy

Which practice best reflects the principle of data minimization in an IoT deployment?

  1. Collecting every available sensor field so future analytics needs are covered
  2. Collecting only the data fields needed for the stated purpose and limiting retention accordingly Correct answer.
  3. Encrypting all collected data so that collection scope becomes irrelevant
  4. Retaining raw sensor data indefinitely in case it is needed for audits

Explanation

Data minimization means limiting collection to what is necessary for a defined purpose and not keeping it longer than needed. Encryption protects data that is held but does not reduce the privacy exposure created by collecting or retaining excessive data.

Question 6Fundamental concepts and principles of IoT security and privacy

An IoT device supports remote firmware updates. Why does the guidance treat a secure update mechanism as a security requirement rather than a convenience feature?

  1. Because updates eliminate the need for authentication between devices and services
  2. Because updates guarantee that the device will comply with privacy law in every jurisdiction
  3. Because without a trusted update path, known vulnerabilities cannot be remediated once devices are deployed in the field Correct answer.
  4. Because updates are the only way to change device configuration settings

Explanation

Devices are often deployed for years in places that are hard to reach, so the ability to deliver authenticated updates is what allows vulnerabilities to be fixed after shipment. Without it, a flaw discovered post-deployment may remain exploitable for the device's whole service life.

Question 7Fundamental concepts and principles of IoT security and privacy

Which risk is most specific to IoT devices that remain in service for a decade or more?

  1. The device may need more frequent user interaction than a desktop computer
  2. The device may become unsupported while still deployed, leaving known vulnerabilities unpatched Correct answer.
  3. The device may consume more bandwidth than a smartphone
  4. The device may require a larger screen than originally planned

Explanation

Long operational lifetimes mean a device can outlive its vendor's support period, so vulnerabilities disclosed later may never be fixed. The guidance highlights lifecycle planning, including support duration, as a way to manage this exposure.

Question 8Fundamental concepts and principles of IoT security and privacy

What does the principle of 'security by design' require in the context of an IoT product?

  1. Documenting security risks without changing the product design
  2. Relying on network perimeter firewalls to protect every device
  3. Embedding security considerations into requirements, architecture, and development from the outset Correct answer.
  4. Adding security features only after a penetration test reveals problems

Explanation

Security by design means security is treated as a design objective from the beginning, shaping requirements and architecture rather than being retrofitted. Retrofitting is costlier and often leaves structural weaknesses that patches cannot remove.

Question 9Fundamental concepts and principles of IoT security and privacy

A smart home hub collects occupancy patterns to automate lighting. Which privacy consideration is most directly raised by this function?

  1. The hub may use a wireless protocol that is incompatible with older bulbs
  2. The hub may consume standby power when no lights are on
  3. The collected patterns can reveal when the home is empty, creating both privacy and physical safety concerns Correct answer.
  4. The device may need a firmware update to support new bulb types

Explanation

Occupancy data is behavioral information about people in a private space, and inferences from it can expose absence from the home. The guidance stresses assessing privacy impact of data collection and inference, not only the functional benefit.

Question 10Fundamental concepts and principles of IoT security and privacy

Which control most directly addresses the risk of unauthorized devices joining an IoT network?

  1. Increasing the transmit power of the gateway antenna
  2. Compressing telemetry payloads before transmission
  3. Enforcing network admission control with authenticated device identities Correct answer.
  4. Rotating the display language of the device management console

Explanation

Admission control verifies that a device is authorized and authenticated before it can join and exchange traffic. This limits rogue or compromised devices from entering the network and interfering with legitimate ones.

Question 11Fundamental concepts and principles of IoT security and privacy

Why does the guidance recommend that IoT devices avoid exposing unnecessary network services?

  1. Unnecessary services prevent the device from receiving firmware updates
  2. Each exposed service increases the attack surface and the chance that a vulnerable interface can be reached Correct answer.
  3. Exposed services always consume more battery than encrypted services
  4. Exposed services make the device incompatible with cloud backends

Explanation

Every reachable service is a potential entry point, and unused services add exposure without adding value. Reducing the attack surface by disabling unneeded interfaces is a basic hardening measure for constrained devices.

Question 12Fundamental concepts and principles of IoT security and privacy

A vendor wants to log device telemetry for diagnostics. Which approach best aligns with privacy-protective logging?

  1. Log all raw payloads permanently so any future issue can be investigated
  2. Disable logging entirely to avoid any privacy risk
  3. Log data without timestamps so it cannot be linked to individuals
  4. Log only the fields needed for diagnostics, with defined retention and access restrictions Correct answer.

Explanation

Privacy-protective logging limits content to what is necessary, sets a retention period, and restricts who can access the logs. This preserves diagnostic value while reducing the likelihood that logs become a reservoir of personal data.

Question 13Fundamental concepts and principles of IoT security and privacy

Which statement about transparency toward users of IoT devices is most consistent with the guidance?

  1. Transparency is satisfied by publishing the source code of the device firmware
  2. Users should be informed about what data the device collects and for what purpose, in understandable terms Correct answer.
  3. Transparency is unnecessary when the device is installed in a commercial rather than residential setting
  4. Transparency requires disclosing every third-party supplier in the device bill of materials

Explanation

Transparency centers on giving people clear information about collection purposes and how data is used, so they can make informed choices. Publishing code or supplier lists may support scrutiny but does not by itself inform users about data practices.

Question 14Fundamental concepts and principles of IoT security and privacy

What is the primary purpose of assigning a unique identity to each IoT device in a deployment?

  1. To guarantee that the device will never be physically stolen
  2. To allow the device to operate without any network configuration
  3. To reduce the amount of power the device draws during idle periods
  4. To ensure the device can be distinguished for authentication, authorization, and audit purposes Correct answer.

Explanation

Unique identity lets a system know which device is acting, apply the right permissions, and trace events to a specific asset. Without distinguishable identities, authorization and accountability become unreliable.

Question 15Fundamental concepts and principles of IoT security and privacy

An attacker floods an IoT gateway with traffic so that legitimate sensor readings are delayed. Which security objective is most directly violated?

  1. Confidentiality
  2. Non-repudiation
  3. Data minimization
  4. Availability Correct answer.

Explanation

Availability means data and services are accessible when needed, and a flood that delays legitimate readings undermines that objective. Confidentiality concerns disclosure, not disruption of timely access.

Question 16Fundamental concepts and principles of IoT security and privacy

Why is mutual authentication particularly important between an IoT device and its backend service?

  1. Because mutual authentication guarantees the device firmware is free of vulnerabilities
  2. Because the device must trust the service it sends data to, and the service must trust the device it accepts data from Correct answer.
  3. Because mutual authentication removes the need to manage device identities
  4. Because mutual authentication eliminates the need for encryption of the traffic

Explanation

In a two-way exchange, each side needs assurance about the other: the device should not send data to an impostor service, and the service should not accept data from an unauthorized device. Mutual authentication establishes both directions of trust.

Question 17Fundamental concepts and principles of IoT security and privacy

Which consideration makes privacy risk assessment for IoT different from assessing a conventional web application?

  1. IoT privacy risk depends only on the size of the device's screen
  2. IoT devices never process personal data and therefore need no assessment
  3. IoT devices often collect data continuously and unobtrusively from physical spaces, so people may not be aware of collection Correct answer.
  4. IoT privacy risk is limited to the data stored on the device itself

Explanation

Continuous, ambient sensing can capture information about people who did not actively engage with the device and may not realize it is collecting. This invisibility raises the stakes for assessing purpose, notice, and necessity of collection.

Question 18Fundamental concepts and principles of IoT security and privacy

Which measure best protects data at rest on a constrained IoT device that may be physically accessible to attackers?

  1. Storing sensitive data in encrypted form with keys protected by hardware-backed storage Correct answer.
  2. Storing data only during business hours to reduce exposure time
  3. Writing data to a plaintext file that is hidden from the user interface
  4. Relying on the device's plastic enclosure to prevent access to the storage chip

Explanation

Physical access defeats simple obscurity, so sensitive data should be encrypted and the keys protected by hardware root-of-trust mechanisms where available. This limits what an attacker gains from extracting the storage medium.

Question 19Fundamental concepts and principles of IoT security and privacy

What role does a hardware root of trust play in IoT security?

  1. It provides an anchor for verifying that software started in a trusted state and for protecting keys Correct answer.
  2. It automatically anonymizes all personal data collected by the device
  3. It guarantees the device will never be affected by a network attack
  4. It replaces the need for any software security controls

Explanation

A hardware root of trust offers an immutable basis for secure boot, attestation, and key protection, so trust can be established from the lowest layer. It supports software security rather than substituting for it.

Question 20Fundamental concepts and principles of IoT security and privacy

A team plans to reuse a single symmetric key across an entire product line to simplify manufacturing. What is the main security objection to this plan?

  1. Symmetric keys require more processing power than public-key operations in all cases
  2. Compromise of one device exposes every device that shares the key, and revocation becomes impractical Correct answer.
  3. Symmetric keys cannot be used to protect data in transit
  4. Reusing keys prevents the device from connecting to a network at all

Explanation

A shared key collapses the security of the whole population into a single secret, so one extraction compromises all devices and makes selective revocation impossible. Per-device keys allow a compromised unit to be isolated without recalling the fleet.

Question 21Fundamental concepts and principles of IoT security and privacy

Which practice best supports accountability in an IoT system that performs automated actions on the physical environment?

  1. Maintaining tamper-evident records of which device or operator triggered each action Correct answer.
  2. Deleting action logs immediately after execution to save storage
  3. Allowing anonymous commands so operators are not identified
  4. Disabling all automated actions to avoid attributing them

Explanation

Accountability requires that actions can be attributed to a responsible device or person after the fact. Tamper-evident records preserve that attribution even when automated behavior affects the physical world.

Question 22Fundamental concepts and principles of IoT security and privacy

What is the purpose of secure boot in an IoT device?

  1. To speed up the device's startup time for better user experience
  2. To compress firmware images so they fit in smaller memory
  3. To verify the integrity and authenticity of firmware before it executes Correct answer.
  4. To encrypt all network traffic generated by the device

Explanation

Secure boot checks that the software about to run is authentic and unmodified, blocking tampered firmware from executing. It addresses integrity at startup rather than performance or network confidentiality.

Question 23Fundamental concepts and principles of IoT security and privacy

An organization wants to decommission a batch of IoT devices. Which action best addresses privacy and security at end of life?

  1. Securely erasing credentials and personal data and revoking the devices' access rights Correct answer.
  2. Leaving stored data on the devices so they remain usable if redeployed
  3. Transferring the devices to another site without changing their configuration
  4. Publishing the device serial numbers to help future owners identify them

Explanation

End-of-life handling should remove residual data and credentials and revoke access so retired devices cannot be reused to enter the system. This prevents old devices from becoming a source of data leakage or unauthorized access.

Question 24Fundamental concepts and principles of IoT security and privacy

Which scenario best illustrates a privacy harm arising from inference rather than from direct disclosure of collected data?

  1. A sensor's firmware is replaced with a malicious version
  2. A gateway's routing table is corrupted, causing packet loss
  3. A smart meter's fine-grained consumption pattern is analyzed to deduce a household's daily routine Correct answer.
  4. A device's stored password file is copied by an attacker

Explanation

Inference harms arise when analysis of data reveals facts about people that were not explicitly collected, such as routines derived from energy usage. The raw data may not contain a routine, but the derived insight still affects privacy.

Question 25Fundamental concepts and principles of IoT security and privacy

Why does the guidance emphasize understanding the data flows of an IoT system across devices, gateways, cloud services, and mobile apps?

  1. Because gateways are always the most secure component and need no controls
  2. Because mobile apps are outside the scope of IoT security
  3. Because data flows determine the physical dimensions of the device
  4. Because privacy and security controls must be applied wherever data is processed or stored along the whole chain Correct answer.

Explanation

IoT systems distribute processing across many components, and a weakness at any hop can expose data or disrupt the service. Mapping flows makes it possible to place controls and assign responsibility at each stage.

Question 26Fundamental concepts and principles of IoT security and privacy

In the ISO 27400 view of IoT security, what distinguishes an IoT device from a conventional IT endpoint?

  1. It is exempt from lifecycle security because it has no stored data
  2. It always runs a full general-purpose operating system with local user accounts
  3. It communicates only over short-range radio and never reaches the internet
  4. It interacts with the physical world through sensors and actuators while often lacking direct human administration Correct answer.

Explanation

The defining trait of IoT is the coupling of networked computing with sensing or actuation in the physical environment, frequently with no operator present. This combination creates safety, privacy, and management concerns that ordinary IT endpoints do not raise in the same way.

Question 27Fundamental concepts and principles of IoT security and privacy

Which pairing correctly matches an IoT security objective with the harm that its failure causes?

  1. Authentication failure: a device uses more power than its battery budget
  2. Integrity failure: a legitimate user is temporarily locked out of the console
  3. Confidentiality failure: an unauthorized party reads stored sensor data Correct answer.
  4. Availability failure: a firmware image is read by a third party

Explanation

Confidentiality protects data from unauthorized disclosure, so reading stored sensor data without authorization is exactly the harm it prevents. The other pairings attach a consequence to an objective that does not govern that consequence.

Question 28Fundamental concepts and principles of IoT security and privacy

A fitness wearable transmits heart-rate readings to a phone app. Under the guidance, which element is personal data in this flow?

  1. The battery level reported in the device status message
  2. The firmware build number reported at connection
  3. The Bluetooth radio frequency band used for transmission
  4. The heart-rate readings linked to an identifiable wearer Correct answer.

Explanation

Personal data is information relating to an identified or identifiable individual, and health measurements tied to a wearer clearly qualify. Technical attributes such as radio band, build number, or battery level are not personal data unless linked to a person.

Question 29Fundamental concepts and principles of IoT security and privacy

Which statement best captures the relationship between security and privacy in IoT according to the guidance?

  1. Privacy is fully achieved once strong encryption is deployed on every device
  2. Security measures support privacy, but privacy also requires limits on lawful collection and use Correct answer.
  3. Security and privacy are competing goals that cannot be pursued together
  4. Privacy applies only to data held in cloud backends, not on devices

Explanation

Security is a necessary foundation for privacy because unprotected data cannot be kept private, yet privacy adds requirements about purpose, minimization, and lawful use that encryption alone does not satisfy. Treating the two as identical or opposed misreads the guidance.

Question 30Fundamental concepts and principles of IoT security and privacy

A city deploys air-quality sensors on lampposts. Which stakeholder group is most directly affected by the privacy implications of the deployment?

  1. The manufacturer's component suppliers
  2. Residents and passers-by in the monitored areas Correct answer.
  3. The electricity utility billing the city
  4. The logistics firm delivering the lampposts

Explanation

Privacy impact falls on the individuals whose environment is observed, since sensor data may reveal activity or occupancy patterns about them. Suppliers, utilities, and delivery firms have commercial relationships with the deployment but are not the data subjects.

Question 31Fundamental concepts and principles of IoT security and privacy

What does the principle of data minimization require when an IoT device collects environmental measurements?

  1. Collecting only the data needed for the stated purpose and retaining it no longer than necessary Correct answer.
  2. Collecting everything possible so future analytics are never blocked
  3. Reducing the number of devices deployed to lower cost
  4. Compressing payloads so less bandwidth is consumed

Explanation

Data minimization limits collection to what is adequate and relevant to a defined purpose, and storage limitation bounds retention. It is about the scope and duration of personal data processing, not about device counts or payload size.

Question 32Fundamental concepts and principles of IoT security and privacy

Which concept describes granting an IoT device only the permissions it needs to perform its defined function?

  1. Separation of duties
  2. Least privilege Correct answer.
  3. Defense in depth
  4. Fail-safe default

Explanation

Least privilege means each component, service, or user receives only the access required for its task, which limits blast radius if it is compromised. The other principles address layered controls, secure default states, and divided responsibilities respectively.

Question 33Fundamental concepts and principles of IoT security and privacy

Why does the guidance treat the constrained nature of many IoT devices as a security consideration rather than only an engineering one?

  1. Small devices are physically too small to be stolen
  2. Constrained devices cannot connect to any network, so they are invisible to attackers
  3. Constraint forces manufacturers to omit logging, which removes all audit obligations
  4. Limited memory and processing power restrict which security controls can run on the device itself Correct answer.

Explanation

Because constrained devices cannot host full security stacks, architects must compensate with gateway, network, and backend controls. This makes resource limits a design-level security decision rather than a purely technical detail.

Question 34Fundamental concepts and principles of IoT security and privacy

A hospital adds connected infusion pumps to its network. Which risk does this introduce that a standard office laptop does not?

  1. The device is assigned an IP address on the network
  2. The device requires periodic software patching
  3. A security compromise could directly endanger patient physical safety Correct answer.
  4. The device consumes electricity during operation

Explanation

When a device actuates on the physical world, a compromise can cause direct physical harm, which is the distinctive cyber-physical risk of IoT. Patching, power, and addressing are shared with ordinary IT equipment and are not unique.

Question 35Fundamental concepts and principles of IoT security and privacy

A manufacturer sells a door lock whose default administrator password is the same on every unit. Which principle does this most directly violate?

  1. Network segmentation
  2. Data minimization
  3. Secure by default configuration Correct answer.
  4. Purpose limitation

Explanation

Secure defaults require that a device ship in a state that is not trivially exploitable, and a shared factory password fails that test. Minimization and purpose limitation concern personal data use, while segmentation concerns network topology.

Question 36Fundamental concepts and principles of IoT security and privacy

During design review, a team maps every place sensor data is stored, processed, and forwarded. Which security and privacy benefit does this data-flow mapping primarily provide?

  1. It removes the need for user consent
  2. It reveals where personal data is exposed and which trust boundaries need controls Correct answer.
  3. It eliminates the need for encryption at rest
  4. It guarantees the product will pass a penetration test

Explanation

Mapping flows shows where data crosses trust boundaries, which is where interception, over-collection, and unauthorized access can occur, so controls can be placed deliberately. It is an analysis input, not a certification or a substitute for consent or encryption.

Question 37Fundamental concepts and principles of IoT security and privacy

An IoT vendor wants to reuse one global signing key to authenticate firmware for all its products. What is the principal security concern?

  1. A single key compromise would allow malicious firmware to be accepted across the entire product fleet Correct answer.
  2. Signing would become slower as the number of products grows
  3. Firmware images would become too large to store on devices
  4. Devices would be unable to verify signatures offline

Explanation

Key scope determines blast radius: one key protecting every product means one leak endangers every product. Good practice limits key scope and supports revocation and rotation so compromise is contained.

Question 38Fundamental concepts and principles of IoT security and privacy

A smart meter reports consumption every fifteen minutes. Which privacy risk arises from the granularity of the reported consumption data?

  1. Fine-grained consumption readings can reveal occupancy and behavioral patterns through inference Correct answer.
  2. The interval causes the meter to consume more energy
  3. Frequent reporting prevents firmware updates
  4. The interval makes the device ineligible for network segmentation

Explanation

High-frequency metering produces a detailed time series from which household routines and occupancy can be inferred even without names attached. The risk comes from the granularity of collection, which is why aggregation or reduced frequency is sometimes preferred.

Question 39Fundamental concepts and principles of IoT security and privacy

What is the security purpose of verifying a device's identity before it is allowed to join an operational IoT network?

  1. To reduce the manufacturing cost of each device
  2. To increase the wireless signal range of the device
  3. To guarantee the device will never need a firmware update
  4. To prevent unknown or impersonating devices from accessing network resources and data Correct answer.

Explanation

Identity verification at admission ensures only known, authenticated devices can consume and produce data on the network. This blocks rogue devices and impersonation, which are common IoT attack vectors.

Question 40Fundamental concepts and principles of IoT security and privacy

A product team proposes to store a device's private key in plaintext flash memory on a physically accessible board. Which alternative best reflects the guidance?

  1. Store the key in a protected hardware element such as a secure element or TPM Correct answer.
  2. Store the key in a file with a random-looking filename
  3. Store the key only in the device's RAM at runtime and lose it on reboot
  4. Encode the key in Base64 to obscure it

Explanation

Keys should be held in hardware that resists extraction, so physical access does not automatically yield the secret. Obscuring techniques and RAM-only storage do not provide durable protection.

Question 41Fundamental concepts and principles of IoT security and privacy

An IoT system logs every sensor reading together with a device identifier and a user account name. Which change best reduces privacy risk while preserving operational diagnostics?

  1. Replace the account name with a rotating pseudonym and restrict access to the logs Correct answer.
  2. Store the logs in a public bucket so researchers can audit them
  3. Increase the logging frequency to capture more context
  4. Delete all logs so no diagnostic data exists

Explanation

Pseudonymization and access restriction reduce identifiability and exposure while keeping the diagnostic value of the logs. Deleting logs destroys accountability, and publishing or expanding collection worsens the risk.

Question 42Fundamental concepts and principles of IoT security and privacy

Why does the guidance recommend that IoT devices fail to a safe state when a security check cannot be completed?

  1. Because safe-state behavior removes the need for authentication
  2. Because it allows the device to skip logging of the failure
  3. Because an unverified condition may indicate attack, and the physical world must be left in a safe posture Correct answer.
  4. Because failing open improves user convenience at all times

Explanation

When integrity or authentication cannot be established, the device may be under attack or malfunctioning, so defaulting to a safe physical state limits harm. This is the fail-safe default principle applied to cyber-physical systems.

Question 43Fundamental concepts and principles of IoT security and privacy

Which activity best corresponds to a privacy risk assessment performed early in an IoT product lifecycle?

  1. Benchmarking battery life against competitor products
  2. Identifying personal data flows, purposes, and potential harms before the design is fixed Correct answer.
  3. Auditing the supplier's factory for component quality
  4. Penetration testing the finished firmware for memory corruption bugs

Explanation

Privacy risk assessment examines what personal data is processed, why, and what harms could result, and it is most effective before design decisions harden. Penetration testing addresses technical vulnerabilities, not privacy purposes or harms.

Question 44Fundamental concepts and principles of IoT security and privacy

A vendor plans to share aggregated device telemetry with a research partner. Which condition best aligns with the guidance?

  1. Verify that the aggregation genuinely prevents re-identification before sharing Correct answer.
  2. Share raw records as well so the partner can validate the aggregation
  3. Assume aggregation is always sufficient regardless of dataset size
  4. Share the data without informing users because it is aggregated

Explanation

Aggregation reduces identifiability only if re-identification is actually prevented, which depends on granularity and dataset size. Sharing raw records or skipping transparency would defeat that protection.

Question 45Fundamental concepts and principles of IoT security and privacy

Which statement best explains why IoT devices often require compensating controls at the gateway or backend?

  1. The devices never communicate outside a local network
  2. The devices may lack the resources to run full security functions locally Correct answer.
  3. The devices are legally prohibited from using cryptography
  4. The devices are always physically inaccessible to attackers

Explanation

Resource limits can prevent constrained devices from hosting comprehensive security functions, so gateways and backends take on authentication, monitoring, and filtering duties. This is a deliberate architectural response to device constraints.

Question 46Fundamental concepts and principles of IoT security and privacy

An attacker gains control of a smart thermostat and uses it as a launch point to scan the home network. Which security principle would most directly have limited the resulting exposure?

  1. Increasing the thermostat's display brightness
  2. Reducing the thermostat's sampling rate
  3. Shortening the thermostat's warranty period
  4. Segmenting IoT devices onto a separate network from personal computers Correct answer.

Explanation

Network segmentation limits lateral movement, so a compromised IoT device cannot easily reach laptops and other sensitive hosts. The other options affect usability or commercial terms and provide no containment.

Question 47Fundamental concepts and principles of IoT security and privacy

A device's firmware is signed by the manufacturer, but the bootloader accepts any image when the signature check fails to parse. What is the most accurate description of this weakness?

  1. The verification logic is not fail-secure, so malformed input can bypass the integrity check Correct answer.
  2. The device is using symmetric instead of asymmetric cryptography
  3. The firmware image is too large for the bootloader to verify
  4. The signing key is too short to provide adequate entropy

Explanation

A verifier that treats an unparseable signature as acceptable fails open, which an attacker can exploit by supplying malformed data. Secure boot requires that any verification failure result in rejection.

Question 48Fundamental concepts and principles of IoT security and privacy

A manufacturer wants to show that its connected camera meets the guidance's expectations for security and privacy. Which approach best reflects an accountability-oriented posture?

  1. Delegating all security responsibility to the end user
  2. Relying on the fact that the camera is inexpensive and therefore a low-value target
  3. Publishing a marketing claim that the camera is fully secure
  4. Documenting design decisions, risk assessments, and controls, and making them available for independent review Correct answer.

Explanation

Accountability requires demonstrable evidence that risks were assessed and controls chosen deliberately, which documentation and independent review provide. Unsupported claims, assumed low value, and shifting duties to users do not demonstrate diligence.

Question 49Fundamental concepts and principles of IoT security and privacy

A vendor argues that because its devices never store names or addresses, privacy is irrelevant to the product. Which reasoning most accurately evaluates this argument?

  1. It is sound because privacy law applies only to cloud databases
  2. It is sound because personal data always requires an explicit name field
  3. It is flawed because pseudonymous or device-level data can still be linked to individuals and reveal behavior Correct answer.
  4. It is flawed because device identifiers must always be published openly

Explanation

Identifiability can arise through linkage and inference even without names, so device identifiers and behavioral traces may constitute personal data. The absence of name fields therefore does not settle the privacy question.

Question 50Fundamental concepts and principles of IoT security and privacy

A fleet of devices uses certificates with a ten-year validity and no revocation mechanism. Which risk does this configuration most directly create?

  1. Certificate validity will slow the devices' sensor sampling
  2. The devices will be unable to perform symmetric encryption
  3. The certificates will expire before the devices are manufactured
  4. A compromised device credential remains trusted for years with no practical way to withdraw it Correct answer.

Explanation

Without revocation, a stolen or extracted credential cannot be distrusted until expiry, leaving a long exploitation window. Credential lifetime and revocation capability are therefore core lifecycle design decisions.