Default Security of the Schema Directory Partition
The default security descriptor for the schema directory partition comprises the following:
Write property permission on the fSMORoleOwner attribute to the Schema Administrators group. This permission enables members of the Schema Administrators group to forcibly transfer the domain controller where schema changes are made.
Change Schema Master control permission to the Schema Administrators group. This permission enables members of the Schema Administrators group to change (per the Flexible Single-Master Operation [FSMO] protocol) the domain controller where schema changes are made.
Inheritable Full Control permission designated to the Schema Administrators group. By default, the Schema Administrators group is the only group that has write access to the entire schema container. A schema object does not have any exclusive control over its own security, thus the object inherits its security from the schema container.
Replicating Directory Changes, Replication Synchronize, and Manage Replication Topology to the Enterprise Domain Controllers group. These permissions enable the members of the Enterprise Domain Controllers group to manage replication of the schema in the forest automatically.
Replicating Directory Changes, Replication Synchronize, and Manage Replication Topology permissions to the Builtin Administrators group. These permissions enable the administrators per domain controllers to resolve replication issues.
Read permissions designated to the Authenticated Users group. This permission enables the members of the Authenticated Users group the right to read the schema.
Audit successful/failed Writes by the Everyone group. Activating the auditing policy ensures that writes that are performed on the directory (on any object) are audited immediately without the need for any extra user intervention. Inheritable ACE provides a convenient way of removing auditing policy.
Default Security of Attributes and Classes
All attributes and classes inherit security from the ACLs on the Schema container. This ensures that the entire schema is consistent in terms of security.
The initial security allows only Schema Administrators write access to the Schema container