Device and endpoint governance

Introduction

Identity is the root control plane, but the machines people use to access code, Microsoft 365, Azure and customer data become part of the control plane too.

Starting stance: governed BYOD with Intune

For a small remote company, the recommended starting point is usually governed BYOD. It is the simplest device security model to implement, it supports remote work quickly, and it gives the company enough posture evidence to start assessing risk.

The goal is not full device control on day one. Full company ownership takes time, money, logistics and operational maturity. A more pragmatic starting point is to allow staff to use personal devices, install the Company Portal and use a simple Intune setup to deploy Defender automatically. This gives the company enough posture visibility to assess whether devices are secure enough and kept up to date without pretending that personal devices are fully company controlled.

Governed BYOD is a staging point. It lets the company learn which controls matter, which devices are healthy, which access paths are risky and when the move to company-owned devices becomes justified.

This allows the company to:

• Support Teams and Microsoft 365 access from personal devices.
• Onboard devices through Company Portal.
• Install Defender automatically through Intune where practical.
• Gain visibility of device security posture.
• Identify whether staff computers are patched and protected.
• Restrict admin account access to known devices.
• Block privileged access from unknown or unhealthy devices.
• Decide later whether full device management is required.

The important distinction is that BYOD is allowed for normal collaboration, but admin access should be treated differently. Admin roles should only be activated from known devices where practical.

Policy follows implementation

The device policy should match the current stance. If BYOD and Intune are not in place, the company should not pretend a BYOD Intune policy is operating. It should record the intended trigger instead.

As soon as BYOD with Company Portal, Intune, Defender or equivalent tooling is introduced, the company needs a matching device and endpoint policy. The policy should define:

• Which devices can access Microsoft 365, repositories, admin portals and customer data.
• Whether BYOD is allowed for normal collaboration.
• Which activities require a known, compliant or trusted device.
• What Defender or endpoint protection is expected.
• What device posture evidence is reviewed.
• How unhealthy, stale or unknown devices are handled.
• How exceptions are approved and reviewed.

This should be supported by a recurring loop. Run endpoint posture review loop to inspect Intune, Defender, Conditional Access and device health evidence, then raise issues where the current device state does not match the policy or access model.

Cyber Essentials Plus and company-owned devices

Cyber Essentials Plus changes the device-management conversation because the company has to evidence the state of endpoints, software and patching rather than simply describe intent. A lightweight BYOD model can be a sensible early position, but it may not be enough as the company moves beyond initial Production and starts to need stronger external assurance.

The maturity path should be explicit:

• Start with BYOD, Company Portal and Defender for posture visibility.
• Restrict privileged access to known or compliant devices where practical.
• Define the trigger for moving from BYOD to company-owned devices.
• As Production scales, migrate privileged and sensitive work to company-owned devices.
• Enforce stricter rules on operating system versions, browser versions, encryption, endpoint

protection, local admin rights and approved software.

• Record exceptions where people temporarily need BYOD for specific low-risk activities.

The point is not to over-control a tiny startup too early. The point is to avoid discovering during Cyber Essentials Plus, procurement or a customer security review that the company cannot evidence the endpoint controls it has been relying on.

Detailed decision considerations

• BYOD stance and known-device requirements.
• Defender onboarding for staff computers.
• Company Portal onboarding path.
• Simple Intune configuration for BYOD posture visibility.
• Endpoint posture review loop and issue handling.
• Trigger for migrating to company-owned devices.
• Cyber Essentials Plus implications for device evidence and control.
• Which activities are allowed from BYOD devices.
• Which admin activities require a known or compliant device.
• Managed devices versus unmanaged devices.
• Whether Intune is introduced immediately or after the first hires.
• Minimum device baseline: disk encryption, screen lock, supported OS and browser updates.
• Software and version enforcement for company-owned devices.
• Local admin rights on developer machines.
• Lost device process.
• Browser/profile separation for admin work.
• Developer machine access to secrets and production data.

How this evolves as the company grows

• At company setup, BYOD can be pragmatic if access is limited and device posture is visible.

• Before Pilot, device posture matters because staff devices may access systems containing customer or personal data.

• At Production, privileged access should be tied to known, healthy devices and PIM-controlled access paths.

• As the company matures, Cyber Essentials Plus or customer requirements may justify moving from BYOD to company-owned devices.

What an agent should look for

• Can admin access be limited to known devices?

• Is BYOD posture visible?

• What is the trigger for company-owned devices?

What good looks like

The company can explain the decision, show the evidence behind it and identify the next point where the control needs to mature.