Why do non-human identities accumulate more unused privilege than human users?

Why This Matters for Security Teams

Non-human identities tend to accumulate unused privilege because they are provisioned for speed, not stewardship. A service account, API key, or integration token is often granted broad access so deployment can proceed, then left untouched while the underlying workload changes. That creates a gap between what the identity was created to do and what it can still do months later. NHI Mgmt Group’s Ultimate Guide to NHIs — Key Challenges and Risks notes that 97% of NHIs carry excessive privileges, which is a strong signal that overprovisioning is not an edge case but a structural pattern.

The problem is amplified by scale. NHIs outnumber human identities by 25x to 50x in modern enterprises, so even a small drift rate becomes a large exposure surface. Teams often apply human-style assumptions, such as periodic access reviews and manager approval chains, to machine accounts that never “forget” old permissions on their own. The result is privilege that survives application refactors, vendor changes, and pipeline redesigns. OWASP’s OWASP Non-Human Identity Top 10 treats this as a core identity-risk issue, not just a hygiene problem. In practice, many security teams discover the excess only after an integration breaks, a secret is leaked, or an attacker reuses an old entitlement long after the original business need has vanished.

How It Works in Practice

Unused privilege accumulates through a few repeatable mechanics. First, the initial deployment request is usually framed around uptime and delivery, so approvers grant the broadest workable role. Second, the identity is often embedded in CI/CD, scripts, or vendor tooling, which makes it hard to distinguish live use from dormant access. Third, the account owner changes or disappears, but the entitlement set remains because there is no clean offboarding event. NHI Mgmt Group research shows that only 20% of organisations have formal processes for offboarding and revoking API keys, which explains why old access survives operational change.

Good practice is to treat NHI privilege as lifecycle-managed state, not a one-time configuration. That means binding every non-human identity to a named owner, a documented purpose, and an expiry or review cadence. It also means separating standing access from task-specific access. JIT provisioning, short-lived secrets, and workload identity standards such as SPIFFE reduce the window in which privilege can linger. Policy engines should evaluate access at request time, using the current context rather than static role assumptions. For implementations, the OWASP guidance and JetBrains GitHub plugin token exposure are useful reminders that long-lived tokens and toolchain integrations are frequent sources of hidden privilege. The practical control stack is simple to describe, but hard to maintain without automation:

• Inventory every NHI and map it to an owner, system, and business purpose.
• Replace standing secrets with short-lived credentials where possible.
• Review entitlements after deployment, not just at creation.
• Revoke privileges when workloads, vendors, or pipelines change.

This guidance tends to break down in legacy environments where shared service accounts, static credentials, and unmanaged vendor connectors make ownership and expiry difficult to enforce.

Common Variations and Edge Cases

Tighter privilege controls often increase operational overhead, so organisations have to balance least privilege against delivery speed and support burden. That tradeoff is especially visible in systems that cannot easily issue short-lived tokens or where multiple applications share one account. Current guidance suggests that shared credentials should be treated as temporary exceptions, but there is no universal standard for this yet, and many teams are still translating that idea into workable policy. The safest path is to document the exception, reduce the scope as far as possible, and assign a removal date.

Another edge case appears when a machine identity is genuinely long-lived, such as a core platform component. Even then, the permissions attached to that identity should not be long-lived by default. The standing secret may remain, but the authorised actions should still be narrow, monitored, and regularly revalidated. NIST’s OWASP Non-Human Identity Top 10 and NHI Mgmt Group’s Ultimate Guide to NHIs — Key Challenges and Risks both point to the same operational lesson: privilege creep is usually a lifecycle failure, not just a policy failure. Mature teams therefore combine access reviews, secret rotation, and offboarding automation instead of relying on a single control. In environments with heavy third-party integrations, unused privilege often persists because no one system owns the revocation workflow.

Related resources from NHI Mgmt Group

• How should security teams govern non-human identities at scale?
• How should security teams govern non-human identities for compliance?
• Why do non-human identities create more audit risk than human accounts?
• How should security teams govern non-human identities in Salesforce?