Identity-centric least privilege is replacing perimeter trust models

At a glance

What this is: This is an analysis of why perimeter-based trust breaks down when identity, not network location, determines access, with excessive permissions and identity sprawl creating the main exposure.

Why it matters: IAM, NHI, and PAM teams need to treat identity as the control plane for containment, because valid credentials and over-privileged accounts can bypass perimeter logic entirely.

By the numbers:

• Identity security weaknesses play a material role in nearly 90% of cyber incidents today, according to Zero Networks.
• Identity is involved in 89% of incidents investigated for the 2026 Unit 42 Global Incident Response Report, according to Zero Networks.
• Machine identities like service accounts make up more than 70% of networked identities, according to Zero Networks.

Context

Identity-centric least privilege is the practice of limiting access based on the identity making the request, not just where the request comes from or what network segment it traverses. The article argues that perimeter-based assumptions fail once valid credentials, service accounts, and hybrid access paths become the main way attackers move.

The practical problem is privilege creep across both human and non-human identities. Zero Networks cites broad identity sprawl, dormant accounts, and excessive permissions as the conditions that make lateral movement possible even when traditional network controls are present.

The article also shows why this has become an operational governance issue, not just an architecture debate. If identities can reach too widely, the network perimeter stops being the main control point and becomes only one layer in a larger access model.

Key questions

Q: What breaks when perimeter security is treated as the main trust control?

A: Access governance becomes location-dependent instead of identity-dependent. That means users or systems can appear trusted because they are inside the boundary, even when authentication quality, privilege scope, or review cadence is weak. In practice, this creates blind spots that zero trust is meant to remove.

Q: Why do over-privileged identities make lateral movement easier?

A: Over-privileged identities make lateral movement easier because they already hold the permissions needed to talk to many systems, not just the one the task requires. An attacker who captures such an identity can use legitimate access paths to expand reach, blend in with normal activity, and avoid the friction that segmented access would impose.

Q: What are the signs that identity-centric least privilege is not working?

A: Common signs include service accounts that can reach more systems than their application needs, dormant accounts that still retain broad access, and hybrid environments where access rules differ by platform rather than by identity intent. If operators cannot explain why an identity can reach a destination, the policy is probably too loose.

Q: Should security teams prioritise identity segmentation over perimeter hardening?

A: Security teams should prioritise identity segmentation when attackers already use valid credentials, cloud workloads, and service accounts to move inside the environment. Perimeter hardening still matters, but it cannot contain internal abuse by itself. The priority is to shrink what any one identity can do after authentication.

Technical breakdown

Identity segmentation as the new control boundary

Identity segmentation limits where a given user, service account, or workload can authenticate and what it can reach after authentication. Instead of trusting a device or subnet by default, the control uses identity context to constrain east-west movement and reduce the usable blast radius of valid credentials. In practice, this is closer to an authorization fabric than a perimeter firewall rule set. The key technical shift is that access is evaluated continuously against identity and destination, not granted broadly at login and assumed safe afterward.

Practical implication: map high-value identities to narrowly scoped destination sets and remove implicit reachability between tiers.

Why over-privileged identities defeat perimeter trust

Perimeter trust models assume the risky event is entry from outside the boundary, but identity-centric attacks often begin with legitimate authentication. Once an attacker has valid credentials, the problem is no longer network origin but privilege scope, because the identity can be used exactly as designed. Excess permissions turn that single identity into a lateral movement bridge. This is why over-privilege and dormant access are not hygiene issues alone, they are direct enablers of post-compromise expansion.

Practical implication: review access scope on identities that can authenticate broadly, especially service accounts and administrative users.

Real-time enforcement for hybrid and machine identity traffic

The article’s focus on automated, human-on-the-loop enforcement reflects a technical reality: manual segmentation does not scale across cloud, SaaS, and on-premises environments. Identity-aligned policy must adapt to changing workloads, application dependencies, and session context without forcing a fixed human review cycle for every connection. That means policy generation, exception handling, and enforcement need to be tied to observed behavior and approved operational need. For machine identities, this is especially important because service accounts frequently hold permissions that outlast the task they were created for.

Practical implication: automate policy enforcement for hybrid traffic and use observed dependencies to shrink standing access.

Threat narrative

Attacker objective: The attacker wants to turn one valid identity into broad internal access that bypasses perimeter controls and enables lateral movement.

1. Entry occurs when an attacker obtains valid credentials or abuses an identity that is already trusted by the environment, so authentication itself becomes the foothold.
2. Escalation follows when the compromised identity carries permissions far beyond the immediate task, allowing the attacker to access additional systems or control planes.
3. Impact occurs through lateral movement and expanded reach, where the attacker uses identity trust to move across assets and steal data or disrupt operations at scale.

Breaches seen in the wild

• Azure Key Vault Contributor escalation 2024: Datadog found Azure Key Vault Contributor could add itself to access policies and read every secret, key and certificate in a vault.
• Kubeflow cryptomining attacks 2020: Exposed Kubeflow dashboards and a notebook's mounted Kubernetes service account let attackers run cryptominers on tens of ML clusters.

Read and download The State of NHI & AI Agent Breach Report 2026, covering 200+ breaches impacting Non-Human Identities including AI Agents.

NHI Mgmt Group analysis

Identity has become the control boundary, not the network edge: The article shows that perimeter trust models fail when valid credentials are the preferred entry point and identity is the mechanism for movement. That is a governance change as much as a tooling change, because access decisions now have to follow the identity across login, workload, and lateral reach. The practitioner conclusion is that segmentation policy must be built around identity scope, not just network placement.

Excess privilege is now an exposure multiplier: Zero Networks cites 99% of cloud users, roles, and services holding excessive permissions, which means the average identity can do far more than it should. That is not just a permissions problem, it is a containment problem, because broad scope turns a single compromise into a multi-system event. The practitioner conclusion is that privilege boundaries must be treated as blast-radius controls.

Machine identities are driving the governance gap: Service accounts now make up more than 70% of networked identities, so least privilege cannot be managed as a human-only IAM issue. This is where NHI governance and network containment converge: the same identity that enables automation can also become the shortest path to uncontrolled reach if it is over-scoped. The practitioner conclusion is that NHI lifecycle and access scope need one control model.

Dynamic enforcement is the only scalable alternative to static perimeter assumptions: The article’s three-dimensional security model reflects a broader market truth, which is that policy must adapt to identity, device, and traffic context together. Static rules cannot keep pace with hybrid environments or changing application dependencies. The practitioner conclusion is that least privilege at scale depends on automation that understands identity intent and operational necessity.

Identity segmentation is a named concept worth carrying forward: This is the practical expression of identity-centric least privilege, where access is limited by who or what the identity is allowed to reach rather than by broad trust in a zone or subnet. The implication for the field is that identity segmentation is becoming a core governance primitive for both human and non-human access. The practitioner conclusion is that IAM, PAM, and NHI controls should converge on destination-level enforcement.

From our research library:

• 83% of privilege escalation incidents involved no CVE exploitation, according to Verizon's 2026 Data Breach Investigations Report.
• Read next: Ultimate Guide to NHIs — Key Challenges and Risks

What this signals

Identity blast radius is now the practical unit of control: When an identity can touch too many systems, the question is no longer whether the perimeter holds, but how much damage one authenticated session can do. Teams should measure reachability by identity class and remove paths that do not match operational need.

Machine identities need the same containment logic as privileged humans: Service accounts are not a side category in this model, they are the largest source of hidden access scope. Governance programmes that treat them as background infrastructure will keep missing the access paths that matter most.

The next programme shift is from policy ownership to reachability ownership. Security teams need a control model that can explain, for every identity, where it is allowed to go, why it can go there, and what changes when its task is complete.

For practitioners

• Map identity blast radius by role Inventory which users, service accounts, and workloads can reach high-value systems and identify where the reachable set is wider than the business need. Prioritise identities with administrative scope, shared credentials, or cross-environment reach.
• Segment machine identities separately Treat service accounts and application identities as first-class policy subjects, not as extensions of human access. Assign destination restrictions that match application function and remove inherited reach that is only present for convenience.
• Replace static trust with context-aware enforcement Use observed dependencies and approved operational need to generate access rules that change as systems move across cloud, SaaS, and on-premises boundaries. Keep exception handling explicit so temporary access does not become permanent reach.
• Reduce standing privilege on dormant identities Review accounts that have not been used for long periods and strip permissions that are not required for current operations. Identities that are unused but still highly privileged should be treated as containment gaps, not dormant assets.

Key takeaways

• Identity-centric least privilege replaces broad perimeter trust with access limits tied to the specific identity making the request.
• Excess permissions, dormant accounts, and service-account sprawl create the conditions that let one valid credential expand into wider compromise.
• The control objective is not only to block entry but to shrink post-authentication reach so lateral movement cannot scale.

Key terms

• Identity Segmentation: The practice of separating identities by workload, environment, and risk so one credential cannot easily move across unrelated systems. For machine identities, segmentation is a blast-radius control as much as a least-privilege measure, because shared dependencies can turn a single compromise into a wider operational event.
• Identity Blast Radius: The amount of damage a compromised identity can cause across systems, data, and infrastructure. In NHI environments, it is shaped by permissions, network reach, and administrative capability rather than by the credential alone. Reducing blast radius is a containment strategy that limits lateral movement and data exposure.
• Machine Identity: The digital identity of a machine, device, or workload, such as a server, container, or VM, used to authenticate it within a network. Sometimes used interchangeably with NHI, though NHI is the broader category.
• Privilege Creep: Privilege creep is the gradual accumulation of access rights beyond what an identity actually needs. It usually happens when permissions are added for convenience and never removed. For NHIs, privilege creep expands blast radius and makes old credentials far more dangerous than their original purpose suggests.

Deepen your knowledge

NHI governance, identity lifecycle management, and workload identity security are core topics in our NHI Foundation Level course, the industry's only accredited NHI security programme. If you are building or maturing an IAM programme, it is worth exploring.