User-Based Access Control
User-Based Access Control, or UBAC, is an authorization model in which permissions are assigned directly to individual users.
- Acronym
- UBAC
- Synonym
- direct access assignmentuser-based authorization
Definition
User-Based Access Control, or UBAC, assigns permissions directly to a named user rather than through a role, an attribute rule, a relationship, or a policy. It is the simplest model to understand and to implement, and it remains legitimate at small scale, for a handful of specific administrators, or for justified exceptions that no collective model should absorb. Its limits appear with volume: individual assignments accumulate, become difficult to review, are rarely revoked when the person changes position, and make it hard to answer questions such as who can do what and why. UBAC is usually compared with RBAC, ABAC, ReBAC, and PBAC, and often coexists with them for the residual cases.
Why it matters
Understanding UBAC clarifies why direct entitlements are acceptable as an exception but costly as a governance model.
The Ariovis perspective
Direct access assignment is not intrinsically wrong. The problem appears when the exception becomes the dominant model. A sound entitlement model should accept that some exceptions exist, without turning every user into a unique authorization model of their own.
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Common pitfalls
- Direct assignments accumulate silently and become the dominant model, which makes access reviews and revocation unreliable.
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