Use both, but for different purposes. Zero trust provides the assumption that access must be continuously verified, while just-in-time access limits how long elevated authority exists. For endpoint agents, the combination matters because continuous verification alone does not stop overbroad standing access, and just-in-time alone does not solve misuse within a live session.
Why zero trust and just-in-time solve different endpoint agent problems
Zero trust is the access model, just-in-time is the privilege timing model. Endpoint agents often need persistent connectivity, but they should not need persistent elevation. The practical design goal is to verify each request continuously while also shrinking the window in which an agent can act with admin or other high-impact authority.
That distinction matters because an agent can be “trusted enough” to connect and still be too powerful for long-lived use. Zero trust helps constrain where the agent can reach and what must be proven at access time, while just-in-time helps ensure that privileged ability exists only when a specific task requires it.
What breaks when teams treat them as substitutes
If teams choose only zero trust, they may still leave broad standing privilege in place. That means the agent is continuously checked, but once approved it can keep using an overbroad role, token, or session for far longer than the task really needs.
If teams choose only just-in-time, they may narrow the duration of elevation but still rely on weak identity context or permissive trust boundaries. In that case the agent can receive temporary power, yet it may still reach too many systems, reuse credentials too widely, or execute actions with insufficient policy checks.
The safer pattern is to separate the questions, who or what is making the request, what resource is being accessed, and how long privileged authority should last. A good design treats zero trust as the guardrail around access decisions and JIT as the guardrail around privilege lifetime.
What good implementation looks like for endpoint agents
For endpoint agents, the control objective is not merely “allow or deny.” It is to bind access to a verified workload or agent identity, constrain the target scope, and make elevated rights ephemeral. In practice, that means the agent should authenticate as itself, request only the specific privilege needed, and lose that privilege automatically when the task ends.
Teams usually get the most value when they apply strong identity proofing and request-time authorization to the agent, then layer JIT for admin-like actions, break-glass use, or narrow operational tasks. Zero Trust Identity Guide is the right mental model for the continuous-verification side, while Just-in-Time Access and Zero Standing Privilege Guide covers the time-bound elevation side.
When agents depend on short-lived credentials or rotated secrets, the access model and the credential lifecycle have to match. Service Account Security Guide is useful when the endpoint agent is effectively operating like a service principal or automation account that needs disciplined ownership, rotation, and least privilege.
Risk and Threat Considerations
Endpoint agents increase exposure when standing privilege, broad tokens, or cached sessions outlive the task that needed them. The risk is not only external compromise, but also accidental misuse, because an overpowered agent can act faster and farther than a human operator would notice.
Failure mechanism: Continuous verification can be satisfied while privilege remains overbroad, and JIT can be satisfied while a live session still has enough authority to cause damage. If the control design does not bind identity, scope, and session duration together, misuse becomes a matter of timing rather than prevention.
Impact: The result is larger blast radius, harder containment, and more difficult attribution when an agent is abused, misconfigured, or simply given too much authority. Endpoint agents should therefore be treated as high-value execution paths, not as ordinary user sessions with a different login method.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 addresses the attack and risk surface, while NIST Zero Trust (SP 800-207) and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-05 — Overprivileged NHI | Endpoint agents can hold excessive standing authority if not time-bound. |
| NHI-07 — Long-Lived Secrets | Agents often rely on credentials whose lifespan should be minimized. | |
| NHI-10 — Human Use of NHI | Endpoint agents are sometimes operated through human workflows that blur authority boundaries. | |
| Recommendation — Eliminate standing privilege and scope agent access to the minimum required task. Replace long-lived credentials with short-lived secrets and enforced rotation. Separate human approval from agent execution and record who authorized each action. | ||
| NIST Zero Trust (SP 800-207) | Zero Trust Architecture | The question centers on continuous verification and scoped access decisions for agents. |
| Recommendation — Apply zero trust principles so every agent request is explicitly verified and constrained. | ||
| NIST SP 800-53 Rev 5 | IA-9 — Identification and Authentication (Service and Application Accounts) | Endpoint agents act as non-human accounts that must authenticate securely. |
| AC-6 — Least Privilege | JIT access is a least-privilege mechanism that limits overbroad authority. | |
| IA-5 — Authenticator Management | Time-bound access depends on controlled secrets, tokens, and other authenticators. | |
| Recommendation — Use service-account authentication controls that bind the agent to its own verified identity. Grant only the permissions needed for the task and revoke them when the task ends. Manage agent authenticators with expiry, rotation, and tight distribution controls. | ||
Practitioner Guidance
What to verify: Confirm that the agent’s authenticated identity, allowed actions, target systems, and privilege duration are all enforced independently. If any one of those controls is missing, the other two will not adequately contain the agent.
Decision rule: If the agent needs repeated access but only occasional elevation, keep its baseline access under zero trust and reserve JIT for privileged steps. If the agent needs broad standing privilege to function, treat that as an exception that needs redesign, not as a normal operating state.
Practitioner takeaway: Zero trust answers whether the agent should be trusted to connect, JIT answers whether it should remain powerful once connected, and mature endpoint-agent design needs both answers at the same time.
Related resources from NHI Mgmt Group
- Should healthcare teams use the same zero trust model for AI agents and service accounts?
- How should security teams enforce just-in-time access in Zero Trust environments?
- Which frameworks should teams use to govern zero trust access in energy operations?
- How should security teams use device identity in zero trust access decisions?