Principle of Least Privilege
Least privilege grants every user and process only the minimum permissions needed, limiting attack surface and breach impact.
The principle of least privilege (PoLP) states that any user, account, process, or service should have only the permissions strictly required to do its job. Reducing standing access shrinks the attack surface and limits the damage of any compromise.
How It Works
Least privilege applies to people and machines alike. A developer might get read access to logs but not write access to production databases. A microservice might receive a scoped credential that can call one API and nothing else. Permissions are defined narrowly and reviewed regularly.
Common techniques include role-based access control to group permissions by job function, attribute-based access control for fine-grained context-aware rules, and just-in-time access that grants elevated rights only for a short window. Service accounts use scoped tokens, and secrets are rotated frequently. Regular access reviews remove permissions that are no longer needed, fighting "privilege creep."
Why It Matters
Most breaches escalate by abusing excessive permissions. If a compromised account can only touch a narrow slice of the system, an attacker gains little. Least privilege also reduces accidental damage, such as an engineer deleting the wrong resource.
Least privilege is a foundation of zero trust and is required by many compliance frameworks, including SOC 2, PCI DSS, and ISO 27001. It is also a practical operational discipline: tightly scoped access makes audits clearer and incidents easier to contain.
The main challenge is balancing security with productivity. Overly tight permissions frustrate users, while broad grants reintroduce risk. Automated tooling and good role design keep this balance manageable.
Related Terms
Least privilege underpins zero trust and is implemented through role-based access control and attribute-based access control. It works alongside defense in depth and sound secrets management.