# AD Objects

## Security Principal

A security principal object has the `objectSid` attribute.

In Active Directory,

* the user
* computer and
* group object classes are examples of security principal object classes though not every group object is a security principal object.

In AD LDS, an independent mode of Active Directory, any object containing the _msDS-BindableObject auxiliary class_ is a security principal.

## Access Control

Access control is administered at the object level by setting different levels of access, or permissions, to objects, such as Full Control, Write, Read, or No Access.

[Microsoft Learn - Access control in Active Directory](https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc785913\(v=ws.10\))

## Reference

[\[MS-ADTS\]](https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-adts/b645c125-a7da-4097-84a1-2fa7cea07714#gt_4bb21ec2-b7ec-435d-9b7c-1eae5ad8f3da)
