Identity Inheritance (Agent)

Expanded Definition

Identity Inheritance (Agent) describes an AI agent that acts with the permissions of a human user, service account, or parent system, rather than a purpose-built identity of its own. In practice, that inherited trust can expose every application, dataset, and workflow already reachable by the source identity.

The term sits at the intersection of IAM, NHI governance, and agentic execution. It is not the same as delegation in the narrow, controlled sense used by modern identity systems. When teams apply identity inheritance loosely, they often blur authentication, authorization, and tool execution into one shared trust boundary. Guidance is still evolving across vendors, but the security principle is clear: inherited access should be explicitly bounded, observable, and revocable. NIST’s NIST AI Risk Management Framework is useful here because it emphasizes managing AI system risk across the full lifecycle, not just at login time.

The most common misapplication is letting an agent reuse a human session or broad parent-token scope, which occurs when automation is added before identity scoping is redesigned.

Examples and Use Cases

Implementing identity inheritance rigorously often introduces friction, because every agent action must be narrowed, logged, and sometimes re-approved, forcing organisations to weigh speed of automation against blast-radius reduction.

• A support agent drafts and sends responses using the same mailbox permissions as the assigned employee, so the inherited identity can read sensitive threads and access internal attachments unless scopes are reduced.
• An engineering copilot executes code and opens repositories under a developer’s session, which can make one compromised prompt enough to expose far more than the assistant actually needs. NHIMG’s OWASP NHI Top 10 and the external OWASP Top 10 for Agentic Applications 2026 both reflect this class of overreach.
• A finance agent triggers approvals through a parent workflow token, allowing it to move from data retrieval into payment initiation if the inherited role is not split from the action authority.
• An internal research agent inherits a manager’s access to shared drives and messaging, but should only be allowed to query approved sources, not act as the manager across all systems.
• NHIMG’s Ultimate Guide to NHIs is the best reference for seeing how inherited privileges expand the NHI attack surface in real deployments.

Why It Matters in NHI Security

Identity inheritance is a high-risk pattern because it turns human privilege into machine-scale privilege. NHIs already outnumber human identities by 25x to 50x in modern enterprises, and NHIMG reports that 97% of NHIs carry excessive privileges, increasing unauthorised access and broadening the attack surface, as documented in the Ultimate Guide to NHIs.

That matters even more when agents can call tools, move across systems, and persist through long-running sessions. A single inherited credential can become a lateral-movement path, especially if secrets are stored outside controlled vaulting or if the agent is granted access by default instead of by task. In NHI terms, the fix is to prefer purpose-built agent identities, enforce role separation, and align access with OWASP Agentic AI Top 10 guidance and the MITRE ATLAS adversarial AI threat matrix when adversarial tool use is in scope.

Organisations typically encounter the consequence only after a prompt injection, token theft, or accidental data exposure, at which point identity inheritance becomes operationally unavoidable to address.

Related resources from NHI Mgmt Group

• What is a Non-Human Identity (NHI)?
• What is the difference between NHI and machine identity?
• What is the difference between an identity, a credential, and a secret?
• Why has identity replaced the network perimeter as the primary security boundary?