Mandatory Integrity Control is defined using a new access control entry (ACE) type to represent the object's IL in its security descriptor. In Windows, Access Control Lists (ACLs) are used to grant access rights (read, write, and execute permissions) and privileges to users or groups. An IL is assigned to a subject's access token when initialized. When the subject tries to access an object (for example, a file), the Security Reference Monitor compares the integrity level in the subject's access token against the integrity level in the object's security descriptor. Windows restricts the allowed access rights depending on whether the subject's IL is higher or lower than the object, and depending on the integrity policy flags in the new access control entry (ACE). The security subsystem implements the integrity level as a mandatory label to distinguish it from the discretionary access under user control that ACLs provide.
