Within the group of explicit ACEs, access-denied ACEs are placed before access-allowed ACEs.
Ntfs meaning windows#
For Windows 2000 and Windows Server 2003, the canonical order is the following:Īll explicit ACEs are placed in a group before any inherited ACEs. The preferred order of ACEs in a DACL is called the "canonical" order. One or more access-allowed ACEs for trustees listed in the thread's access token explicitly grant all the requested access rights.Īll ACEs have been checked and there is still at least one requested access right that has not been explicitly allowed, in which case, access is implicitly denied.īecause the system stops checking ACEs when the requested access is explicitly granted or denied, the order of ACEs in a DACL is important. The system examines each ACE in sequence until one of the following events occurs:Īn access-denied ACE explicitly denies any of the requested access rights to one of the trustees listed in the thread's access token. If the LSASS finds ACEs, it compares the trustee SID in each ACE to the trustee SIDs that are identified in the thread's access token. If the object's owner has not created any ACEs in the DACL for that object, the system grants access right away. To do this, the LSASS searches the DACL (Discretionary Access Control List) in the SDS data stream, looking for ACEs that apply to the thread.Įach ACE in the object's DACL specifies the access rights that are allowed or denied for a security principal or logon session. When a thread tries to access a securable object, the LSASS (Local Security Authority) either grants or denies access. A token also contains a logon SID (Security Identifier) that identifies the current logon session. The token identifies the user, the user's groups, and the user's privileges. Every process executed on behalf of the user has a copy of the access token. The system creates an access token when the user logs on. Each user logged onto the system holds an access token with security information for that logon session.