Start with unique credentials, MFA, and automatic updates for every device and companion app. Treat each device account as an identity that needs its own password, lifecycle oversight, and patch support. If a device cannot be updated or protected with stronger authentication, it should not remain connected to the environment.
Secure smart devices by treating every device as an identity
Smart devices that collect personal data are not just endpoints, they are authenticated actors with data access. The first job is to make each device individually accountable: unique credentials, MFA where the device or companion app supports it, and a lifecycle that covers enrollment, rotation, suspension, replacement, and retirement. That gives teams a clean way to decide whether the device should still be trusted.
The same logic should extend to the companion app and any cloud service the device depends on. If multiple devices share one login, one compromise can expose the whole fleet. If a device cannot accept updates or stronger authentication, the safest design choice is to remove it from the connected environment rather than accept permanent exposure.
For smart devices that handle personal data, identity data privacy and consent is part of the control plane, not a legal afterthought. Data minimisation, explicit consent handling, and retention limits matter because the device often becomes a long-lived collector of sensitive information rather than a single-purpose sensor.
What breaks most often in connected device environments
The weak point is usually not the hardware itself but the trust model around it. Default passwords, shared accounts, weak pairing flows, and delayed patching turn an ordinary device into a durable access path. Once the device account is treated as disposable, revocation gets missed and a retired device can keep authenticating long after the user stops using it.
Update failure is another common control gap. A device that cannot be patched will accumulate known weaknesses across firmware, companion app, mobile operating system, and backend API dependencies. That risk increases when the device stores identifiers, home or location data, health-related telemetry, or other personal data that would be damaging if exposed or altered.
For teams building policy, the baseline should align to strong access control and device integrity practices such as NIST SP 800-53 Rev 5 Security and Privacy Controls and NIST Privacy Framework. Those references reinforce the two things that matter most here: limit access to what the device truly needs, and govern the personal data it touches as a first-class security concern.
Build the control set around supportability, not convenience
The practical security test is simple: can the vendor still support secure operation across the full device life? That means reliable updates, modern authentication options, clear reset and deprovisioning paths, and a documented end-of-support date. If the answer is unclear, teams should treat the device as a managed exception, not as an ordinary consumer gadget.
When the device talks to a cloud backend or mobile app, the same expectation should apply to the broader service chain. Teams should confirm that the companion app is maintained, that the backend enforces least privilege, and that account recovery does not weaken the original authentication model. A strong device can still be undermined by a weak app or an overexposed API.
For hardening and identity assurance, use NIST Cybersecurity Framework 2.0 to organise the program around governance, protection, detection, response, and recovery, and use NIST SP 800-63 Digital Identity Guidelines when device or user authentication needs a clearer assurance model. For cloud-connected fleets, privacy risk management should be tied to the data the device collects, not just to the network it sits on.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5 and NIST SP 800-63 set the technical controls, while GDPR and ISO/IEC 27001:2022 define the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | IA-5 — Authenticator Management | Device credentials need unique issuance, rotation, and revocation. |
| IA-2 — Identification and Authentication (Organizational Users) | Users managing device access need strong authentication to reduce account misuse. | |
| CM-8 — System Component Inventory | Smart devices must be inventoried to track lifecycle, supportability, and exposure. | |
| Recommendation — Manage device credentials with issuance, rotation, and revocation controls. Require strong user authentication for device administration and access. Maintain an inventory of connected devices and their support status. | ||
| NIST SP 800-63 | Digital Identity Guidelines | Phishing-resistant authentication concepts inform strong device and companion-app access. |
| Recommendation — Use assurance-based authenticator choices for device administration and pairing. | ||
| GDPR | Art. 5 — Principles relating to processing of personal data | Smart devices that collect personal data must minimise and limit processing. |
| Art. 25 — Data protection by design and by default | Security and privacy must be built into device defaults, not added later. | |
| Art. 32 — Security of processing | Authentication, patching, and access controls directly support secure processing. | |
| Recommendation — Minimise device-collected personal data and limit retention to what is necessary. Configure devices so secure and privacy-preserving settings are the default. Protect device-collected personal data with appropriate technical and organisational measures. | ||
| ISO/IEC 27001:2022 | A.8.24 — Use of cryptography | Some connected devices depend on cryptographic protection for access and data security. |
| Recommendation — Use approved cryptography where the device transmits or stores sensitive data. | ||
Practitioner Guidance
What to prioritise: Start with the devices that collect the most sensitive personal data, have the longest expected lifespan, or are hardest to patch. Those create the biggest exposure if they are still trusted after their security model has degraded.
What to verify: Confirm that every device has a unique account, a documented owner, a reset and offboarding path, and a supported update channel. If any one of those is missing, treat the device as unsafe to keep connected.
Common mistake: Teams often secure the phone app but ignore the device account itself. That leaves shared credentials, stale sessions, and orphaned devices able to keep collecting data even after the user believes they are gone.
Practitioner takeaway: The right standard is not whether the device is convenient or popular, but whether it can be individually governed, updated, and removed without leaving a hidden trust path behind.
Related resources from NHI Mgmt Group
- How should healthcare teams secure IoT devices that collect and transmit patient data to the cloud?
- How should teams secure smart devices that use companion apps and remote access?
- How should security teams secure remote access when employees use a mix of company-owned and personal devices?
- How should security teams govern sensitive data after employees download it to managed or personal devices?
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Reviewed and updated by the NHIMG editorial team on October 11, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org