Should organisations use random-looking object IDs as a security control?

Why Random-Looking Object IDs Do Not Replace Authorisation

Random-looking object IDs can make casual guessing harder, but they are not a security boundary. If a system relies on an unguessable identifier instead of checking whether the requester is allowed to see or change the object, it creates an access control flaw. Good designs treat the identifier as a locator, not as proof of entitlement.

That distinction matters because attackers do not need to “guess correctly” forever, they only need one exposed reference path, log leak, referrer leak, browser history artifact, or predictable enumeration route. Once an object can be referenced, the system still has to decide whether the caller owns it, is tenant-bound to it, or has a valid role or scope for it.

For APIs and web applications, OWASP API Security Top 10 is the clearest reminder that broken object-level and function-level authorisation are separate from identifier format. The control failure is not “IDs were guessable”; it is “the server trusted the wrong request context.”

What Random IDs Can Help With, and What They Cannot

A random identifier can reduce opportunistic browsing, accidental disclosure, and low-effort scraping. That is useful, but only as a minor friction layer. It may lower exposure if an ID would otherwise be easy to enumerate, especially in public URLs or client-visible references, but it does not verify ownership, tenant membership, or privilege.

It also does not fix privilege escalation inside the application. If the backend accepts an object ID and does not re-check the caller’s access, a user can still swap one valid ID for another. The weakness is usually in object reference handling, not in the randomness itself.

Frameworks that emphasise least privilege and verification align with this reality. NIST SP 800-207 Zero Trust Architecture reinforces the same pattern: do not trust a visible reference, verify each request. The identifier should never be treated as an access token.

For broader control design, NIST SP 800-53 Rev 5 Security and Privacy Controls supports the separation between identification, authentication, and access enforcement. In practice, that means object access must be decided by policy, not by obscurity.

How to Design Object Access So the ID Is Harmless

The safest pattern is to make every object access path enforce server-side checks based on the caller’s identity, tenant, role, scope, or ownership context. The object ID can still be random, but the decision must be independent of whether the identifier is hard to guess.

That usually means validating three things on every request: the object exists, the caller is authorised for that object, and the object belongs to the expected tenant or security boundary. In multi-tenant systems, tenant binding is essential because a valid object ID from one tenant should never become a usable reference in another.

Where application teams need a verification baseline, OWASP API Security Top 10 is useful because it frames object access failures as authorisation defects to test for explicitly. Random IDs may be part of the implementation, but they are not the test condition.

At the identity and access layer, NIST SP 800-63 Digital Identity Guidelines is relevant when the object decision depends on the strength of the authenticated session behind the request. Strong authentication helps establish who is asking, but the application still has to decide what that identity may do.

Risk and Threat Considerations

Using random-looking IDs as a substitute for access control creates a false sense of security. The main risk is object-level exposure: once a valid reference is discovered, the system may disclose or modify another user’s data, especially where logs, URLs, exports, or client-side state expose the identifier.

Failure mechanism: The application accepts a referenced object without re-checking ownership, tenant context, or permission, so a valid but unauthorised ID becomes enough to reach the data.

Impact: Attackers can enumerate records, cross tenant boundaries, retrieve sensitive data, or perform unauthorised actions even when the identifier is hard to predict.

Practitioner Guidance

What to verify: Test object access with valid identifiers from another user, another tenant, and a lower-privilege role. If the response changes only because the ID changed, the control is incomplete.

Common mistake: Teams often equate “unguessable” with “protected.” That shortcut fails the moment an identifier is leaked, reused, logged, or copied into a context the application does not re-authorise.

What good looks like: The server makes the access decision from authenticated context and policy, and the identifier merely selects a candidate object after those checks pass. If the identifier is hidden, that is a convenience, not a control.

Practitioner takeaway: Treat random-looking IDs as a small reduction in exposure, not as a security control. Real protection comes from independent authorisation, tenant binding, and ownership checks on every object request.

Related resources from NHI Mgmt Group

• How should security teams use IAST and RASP in NHI governance?
• How should security teams use identity attributes to improve role-based access control in complex organisations?
• How should organisations use cyber insurance loss control services to improve identity security before policy renewal?
• How should security teams prioritise NHI remediation in cloud environments?