Access control

Ensures that components operate with only the permissions they require, reducing unnecessary access.

Web application: granting API keys broader scopes than needed; Operating system: running services with root privileges unnecessarily; Cloud infrastructure: assigning IAM roles that include unused actions

Enterprise applications, cloud services, operating system services, containerized deployments, microservice architectures

Determine required actions → assign only those permissions → deny all others

• role-based access control
• permission matrix
• sandbox
• capability
• ACL

• Using role-based access control instead of fine-grained capabilities – easier to manage but may be less precise
• Granting admin rights as a shortcut – quick but violates least privilege

Granting broad administrator rights by default → leads to unnecessary attack surface; Assuming default user accounts have minimal rights without verification → can cause privilege escalation; Over-restricting permissions during development → results in frequent permission errors and delays

Role-based access control vs. attribute-based access control – RBAC groups permissions, ABAC evaluates attributes; Defense in depth – broader security strategy that includes least privilege as one layer

Coming from Windows: assuming all users run as Administrator → need to enforce non-admin accounts in Linux and container environments

• Principle of least privilege
• defense in depth
• role-based access control
• capability-based security

1) Do not apply when a temporary elevated privilege is required for setup or migration tasks; 2) Overly restrictive permissions can cause runtime failures and increase debugging overhead; 3) Boundary condition: privilege escalation mechanisms (e.g., sudo) must be tightly controlled and audited

Reduces attack surface, limits impact of compromised components, and helps meet compliance requirements such as PCI-DSS and HIPAA.

Like giving a guest only the key to the room they need, not the whole house.

Least privilege is a guiding security principle rather than a specific API; implementation details vary across platforms and languages.

Combine with defense-in-depth strategies and automated permission audits