Least privilege across human, machine, and AI identities

At a glance

What this is: NHI Mgmt Group's analysis, drawing on Securden's blog post: Least privilege across human, machine, and AI identities is defined as the access-control approach needed because valid credentials and standing access, not only software flaws, are now the dominant access-control risk.

Why it matters: It matters because IAM, PAM, and NHI programmes have to scope access to the task and the session, or they will keep granting attackers broad blast radius through legitimate credentials.

Context

Least privilege is the principle that every identity should hold only the permissions needed to do its current job, nothing more. In practice, that means the control has to follow the identity type, whether the subject is a human user, a service account, or an AI-driven workflow.

The governance gap is not the definition itself but the operationalisation of it across mixed identity estates. When access is granted broadly and reviewed later, standing privilege, hardcoded secrets, and inherited permissions create a much larger attack surface than most programmes admit.

Key questions

Q: What breaks when standing privilege exists for non-human identities?

A: A single compromised credential can be reused across systems, extended over time, and combined with lateral movement. Standing privilege turns routine access into reusable attack capacity. In practice, that means one failure can become a multi-system incident before defenders notice.

Q: Why do valid credentials create so much risk in API environments?

A: Valid credentials are risky when the API trusts them too broadly. Service accounts, API keys, and tokens often outlive the task they were created for or carry scopes wider than the workflow needs. Once an attacker finds that mismatch, abuse looks legitimate to the application, which is why privilege scope and expiry matter as much as authentication.

Q: How do security teams know whether least privilege is actually working?

A: Least privilege is working when identities have narrowly scoped permissions, unused credentials are removed or quarantined, and repeated access reviews consistently shrink entitlements. A good signal is whether a compromised identity would be unable to move beyond one bounded workflow. If broad resource reach still exists, the control is not effective.

Q: What is the difference between just-in-time access and standing privilege?

A: Just-in-time access grants privilege only for a defined task window, while standing privilege remains active until someone removes it. JIT reduces exposure by shrinking the time an identity can be abused, but standing privilege creates a constant attack surface. For NHI programs, the difference is often the difference between contained risk and persistent exposure.

Technical breakdown

Least privilege across humans, service accounts, and AI identities

Least privilege is not a human-only policy. For humans it governs interactive access, for service accounts it governs technical permissions, and for AI identities it has to govern what the actor can invoke at runtime. The article’s key point is that the same control principle applies, but the enforcement mechanism differs by actor type. Human access can be reviewed against roles, machine access has to be scoped to workloads and secrets, and AI access has to be constrained around task, tool, and execution boundaries.

Practical implication: classify each identity type separately before applying least-privilege policy.

Why valid credentials now matter more than exploits

The article frames valid credentials as the dominant breach path because attackers increasingly use what already exists rather than breaking in through software defects. That changes the control problem from perimeter hardening to permission quality. If an account, token, or service identity already has broad reach, compromise becomes an access problem, not an exploitation problem. Least privilege reduces the usable value of stolen credentials by shrinking what any one identity can do even after authentication has succeeded.

Practical implication: prioritise permission scope and credential containment over assuming patching alone will close the risk.

Runtime-scoped access is the real control boundary

The article repeatedly points to time-bound access, just-in-time elevation, session recording, and secret retrieval at runtime as the practical expression of least privilege. Those controls matter because static credentials and standing entitlements outlive the task they were meant to support. Once access is permanent, every compromise inherits an unnecessary blast radius. Runtime-scoped control turns privilege into something temporary, reviewable, and attributable instead of durable and implicit.

Practical implication: move privileged and machine access toward just-in-time issuance and audited session use.

Threat narrative

Attacker objective: The attacker aims to turn legitimate identity access into broad operational reach, data access, or administrative control without needing to exploit a vulnerability.

1. Entry begins with valid credentials, such as a stolen password, API key, or service account secret, rather than a software exploit.
2. Escalation occurs when the compromised identity already has broader permissions than the task requires, allowing the attacker to do more than the original use case needed.
3. Impact follows through lateral movement, data exposure, or privileged action because the account was allowed to operate with standing access.

Breaches seen in the wild

• Smithery.ai MCP hosting breach 2025: A Smithery.ai build flaw gave GitGuardian a live fly.io token controlling 3,000+ hosted MCP servers and the API keys their clients sent.

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

Least privilege has become an identity integrity problem, not just an access review exercise: The article is right to frame PoLP as the control that determines how far legitimate access can travel when credentials are compromised. That matters across human, machine, and AI estates because broad grants turn every authenticated identity into a potential pivot point. The practitioner conclusion is simple: access scope is now a first-order security variable, not an audit afterthought.

Valid credentials are the new default intrusion path: The article’s most important implication is that attackers increasingly win by using credentials that were already accepted by the environment. That makes excessive privilege more dangerous than many technical vulnerabilities because the system itself is authorising the movement. The practitioner conclusion is to treat permission minimisation as breach prevention, not merely governance hygiene.

Runtime-scoped privilege is the named control concept this topic points to: Standing access, hardcoded secrets, and broad entitlements all assume the identity will need the privilege long enough for human review or passive monitoring to matter. That assumption breaks across service accounts and AI-driven workflows because the task window is often much shorter than the review cycle. The practitioner conclusion is to measure privilege by execution window, not by account ownership.

NHI governance and human IAM are converging on the same failure mode: The article shows that the same over-permissioned access pattern now spans employees, service identities, and AI-enabled processes. That convergence means programmes built around separate human and machine controls will miss the real risk, which is unchecked privilege persistence. The practitioner conclusion is to govern entitlement scope and lifecycle as one discipline across all identity types.

Least privilege only works when discovery and revocation are continuous: The article’s operational detail makes clear that visibility alone is not enough if stale accounts, unused permissions, and hardcoded secrets remain active. Once access becomes inventory without enforcement, the environment still carries dormant blast radius. The practitioner conclusion is to pair inventory, revocation, and time-bounding as a single control chain.

From our research library:

• Systems with least-privileged AI access had a 17% incident rate vs 76% for over-privileged systems. Organisations failing to scope AI access properly are 4.5x more likely to experience a security incident, according to the 2026 Infrastructure Identity Survey.
• 97% of NHIs carry excessive privileges, increasing unauthorised access and broadening the attack surface, according to the Ultimate Guide to NHIs.
• Read next: Privileged Access Management Guide

What this signals

Runtime-scoped privilege is becoming the practical boundary for least privilege: Access models built around broad grants and later review cannot keep up with identities that need to act briefly and disappear again. The control has to move closer to issuance time, especially for service accounts and AI-enabled workflows that do not hold access long enough for traditional review cycles to matter.

Hardcoded secrets and standing entitlements should be treated as the same governance problem: Both create durable access that outlives the task and widens blast radius when credentials are exposed. Programmes that still separate secret management from privilege management will miss how attackers chain the two together.

For practitioners

• Map privilege by identity type Separate humans, service accounts, API clients, and AI-driven workflows in the entitlement model so each can be judged by its actual task scope rather than a shared permission template.
• Replace standing access with time-bound elevation Use just-in-time elevation for administrative and high-risk operations so privileged access exists only for the task window and is removed when the session ends.
• Inventory non-human credentials and secrets Discover service accounts, API keys, tokens, SSH keys, and certificates, then remove unused or unmanaged identities that still hold access to production systems.
• Move secret use to runtime retrieval Replace hardcoded secrets in code and CI/CD pipelines with runtime retrieval from a vault so the credential is not sitting exposed in development or deployment artefacts.
• Review cloud entitlements against actual usage Compare granted permissions to observed activity across AWS, Azure, and GCP, then cut back over-allocated rights that are never exercised by the workload.

Key takeaways

• Least privilege is only effective when access scope matches the task for humans, service identities, and AI-driven workflows.
• The article’s core warning is that valid credentials and standing access now drive more compromise potential than broken software alone.
• Programmes need runtime-scoped privilege, time-bound elevation, and continuous removal of unused entitlements to shrink blast radius.

Key terms

• Least Privilege: A security principle requiring that every identity, human or non-human, is granted only the minimum permissions necessary to perform its function. Least privilege is the single most effective control for reducing NHI blast radius.
• Standing Privilege: Standing privilege is access that remains active even when no immediate task requires it. For NHI programmes, it is a common failure mode because long-lived credentials and persistent roles create unnecessary exposure. Reducing standing privilege usually means tighter expiry, on-demand access, and clearer review of who or what still needs access.
• Just-in-Time Elevation: A temporary access pattern that grants a user or system elevated permissions for a limited period. It reduces exposure compared with always-on privilege, but it does not necessarily remove the underlying role or account from the environment, so governance must still address the residual entitlement path.
• Context Retrieval: Context retrieval is the process of supplying an AI system with the files, records, or project state it needs to act effectively. It becomes an identity concern when retrieval scope shapes what the agent can decide, access, and change, making data exposure part of the authorization boundary.

Deepen your knowledge

NHI governance, agentic AI identity, and machine identity lifecycle 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.