Security fundamentals

What is the principle of least privilege?

The principle of least privilege means giving each user, system, or process only the minimum access it needs to do its job, and nothing more. It limits the damage any single account or compromise can cause.

Definition

The principle of least privilege (PoLP) is the security practice of granting every user, account, and process only the access strictly required for its legitimate purpose, and no more.

Background

Least privilege is one of the oldest and most effective ideas in security. In practice it means default-deny access, role-based permissions instead of broad admin rights, just-in-time elevation for sensitive tasks, and prompt removal of access that is no longer needed. It underpins access control expectations in SOC 2 and ISO 27001 and is a building block of zero-trust architectures.

Why it matters

When an account is phished or a service is compromised, least privilege is what decides whether the attacker gets a little or a lot. Tight permissions turn what could be a breach into a contained incident.

Step by step

1. Default to no access; grant permissions explicitly based on role.
2. Use role-based access control rather than handing out broad administrator rights.
3. Separate duties so no single account can both make and approve sensitive changes.
4. Use just-in-time or time-boxed elevation for privileged tasks instead of standing admin access.
5. Review access regularly and revoke what is no longer needed.

Examples

• An engineer gets read access to a data store by default and requests temporary write access only when a task requires it.
• Support staff can view customer records but cannot export them in bulk, limiting the impact of a compromised support account.

Common mistakes

• Handing out admin rights broadly because it is convenient.
• Granting temporary access that never gets revoked.
• Confusing least privilege with a one-time setup rather than something reviews must maintain.

FAQ