How does a permissions boundary affect user permissions?

A permissions boundary is a crucial concept in managing user permissions, particularly in hierarchical permission models like those in cloud environments. This mechanism allows organizations to set limits on what permissions users or roles can take on when they assume a role or are granted policies.

When a permissions boundary is applied, it does not add or grant additional permissions; instead, it establishes a ceiling that restricts the permissions a user can effectively use. This means that even if a user has policies that would typically grant them extensive permissions, the permissions boundary will limit those permissions to what is defined within it. This is particularly useful for enforcing least privilege access principles, ensuring that users only have the necessary permissions they need to perform their job while minimizing potential security risks.

In this context, the other options do not accurately represent the function of a permissions boundary. For example, while a permissions boundary does not create new permissions, it effectively constrains the overall permissions a user can utilize, making it distinct from simply granting access.