Least Privilege Access Model

    Model subjects, resources, actions, and context to implement deny-by-default with safe exceptions—aligned with Zero Trust principles.

    Least Privilege
    Policies
    ZTA
    OT/ICS
    8 min
    Last updated: 2026-01-12

    Overview

    Least privilege means access is granted only when required, for the minimum scope and time, under verified conditions.

    Model

    • Subject: user, device, or workload identity.
    • Resource: application, service, OT asset, or data segment.
    • Action: connect, read, write, admin, or remote console.
    • Context: site, zone, time window, risk score, posture.

    Common patterns

    • Deny-by-default with explicit allow rules.
    • Step-up verification for privileged actions.
    • Time-boxed maintenance access.
    • Break-glass approvals with evidence capture.

    OT notes

    OT safety
    Prefer observe mode first, document dependencies, then enforce in maintenance windows.

    Checklist

    • Define resource criticality tiers.
    • Group identities by role and environment.
    • Document required communication paths.
    • Implement staged enforcement and rollback plans.