Restrict Administrative Privileges with Entra Cloud PKI

The Essential Eight maturity model, maintained by the Australian Cyber Security Centre, treats the control of administrative privileges as one of the foundations of a resilient environment. Attackers who compromise a privileged credential gain the ability to move laterally, disable protections, and extract sensitive data with far greater ease than an ordinary user account allows. For this reason, the Restrict Administrative Privileges strategy asks organisations to limit the number of privileged accounts, validate their ongoing necessity, and strengthen the way those accounts authenticate.

Microsoft has continued to extend the tooling available for this task, and two capabilities in particular are worth close attention. The first is Microsoft Cloud PKI, a service that allows an organisation to run a certificate authority hierarchy from the cloud without maintaining on-premises infrastructure. The second is certificate-based authentication in Microsoft Entra ID, which allows administrators to prove their identity with a cryptographic certificate rather than a password. Read together, these capabilities offer a practical way to raise the assurance of privileged access while reducing the credential theft exposure that concerns security teams across distributed sites.

What the strategy actually requires

Restrict Administrative Privileges is concerned with who holds elevated rights, how often that entitlement is reviewed, and how strongly those accounts are protected. At higher maturity levels the model expects privileged access to be limited to defined tasks, separated from accounts used for email and web browsing, and validated when it is first requested and periodically thereafter. The intent is to shrink the attack surface so that a stolen password, on its own, cannot deliver administrative control of critical systems.

Passwords remain the weakest part of most privileged workflows because they can be phished, guessed, reused, or harvested from memory. Even with multifactor authentication in place, some methods remain susceptible to interception or fatigue attacks. Moving privileged authentication towards a phishing-resistant, certificate-backed method addresses the underlying problem directly, because a certificate stored on secure hardware cannot be typed into a fraudulent portal or replayed from a captured session.

How Microsoft Cloud PKI supports certificate-backed access

Microsoft Cloud PKI, delivered as part of the Microsoft Intune Suite, provides a managed certificate authority that issues and manages certificates for devices and users without the operational burden of running Active Directory Certificate Services on local servers. Certificates can be provisioned automatically to enrolled devices through Intune policy, which removes much of the manual handling that historically made certificate deployment difficult to sustain. This matters for privileged access because it makes it feasible to place a valid, trusted certificate on the specific devices that administrators use for elevated tasks.

Once a certificate authority hierarchy is established, those certificates can underpin authentication to Microsoft Entra ID. Certificate-based authentication allows Entra to accept a client certificate as a primary factor, and it can be combined with a hardware-protected key so that the private key never leaves the device. When an administrator signs in, the service validates the certificate against the configured authority and the associated policies, which means an attacker who obtains a password alone gains nothing usable. The result aligns closely with the phishing-resistant direction that the Essential Eight and broader government guidance encourage.

Relevance to government and mining operations

Government agencies operate under strict expectations for the protection of privileged access, and they are frequently assessed against the Essential Eight as part of assurance activities. Certificate-based administrative authentication gives these agencies a defensible way to demonstrate that elevated access depends on a cryptographic credential bound to a managed device, rather than a shared secret that could be captured. Because Cloud PKI is managed centrally, it also supports consistent policy across departments and reduces the risk that a neglected on-premises certificate authority becomes a liability.

Mining organisations face a different but related challenge, because their operations are often spread across remote sites with limited local IT presence and intermittent connectivity. Administrators may need to manage systems from field locations where the risk of credential interception is harder to control. Provisioning certificates to managed devices and requiring them for privileged sign-in means that access remains protected even when an administrator works far from a corporate network, and it reduces reliance on passwords that could be exposed at any of these distributed sites. This distributed resilience is one of the clearest practical benefits of a certificate-backed approach.

Practical considerations before adoption

Adopting certificate-based privileged authentication is not solely a technical exercise, and it benefits from careful planning. Organisations should map their existing privileged accounts, confirm which devices those administrators use, and decide how certificates will be protected on those devices, whether through a Trusted Platform Module or a physical security key. It is also important to plan the certificate authority hierarchy, define renewal and revocation processes, and ensure that a compromised or lost device can have its certificate revoked promptly.

Equally, the move should be integrated with the wider set of privileged access controls rather than treated in isolation. Conditional access policies can require compliant devices and phishing-resistant methods for administrative roles, while Privileged Identity Management can enforce just-in-time elevation so that entitlements exist only when needed. Combining these controls with certificate-backed authentication produces a layered approach that reflects the intent of the Essential Eight and supports the periodic validation of access that higher maturity levels expect.

References

• ACSC Essential Eight Maturity Model
• Microsoft Cloud PKI overview
• Microsoft Entra certificate-based authentication