What does ACB mean in UNCLASSIFIED

What is an Access Control Block?

An Access Control Block (ACB) is a structure maintained by a system to track access control information related to certain resources such as files, directories, processes, etc. An ACB contains access control lists (ACLs) which specify the permissions applicable to the resource in question. These ACLs define the type of operations that can be performed on the resource and by whom. For example, a file's ACL might specify that only members of a particular group have read or write access to it. The ACB also tracks additional metadata about each resource such as ownership, timestamps for when it was created or modified, etc.

How Does an Access Control Block Work?

When a user attempts to access a resource they will first need to authenticate themselves with their username and password if required by the system. If authentication is successful then the system will look up any associated ACBs in its database via a lookup table. If an ACB exists for this specific resource then the system will compare various elements contained therein against criteria set out within associated ACLs before granting or denying access as appropriate. Finally, if access is approved then associated metadata pertaining to the operation are recorded within the ACB for auditing purposes at some future date if necessary.

Benefits of Using an Access Control Block

The use of Access Control Blocks provides numerous benefits from both a security and operational perspective including:

• Improved Security — By controlling user access to resources using ACLs contained within an ACB malicious actors are much less likely be able to gain unauthorized access compared with traditional authentication methods;

• Enhanced Auditability— By recording all activity related to each resource in its respective ACB full traceability can be established which allows events to be properly monitored and investigated;

• Greater Flexibility —As different resources can have unique rules relating to their usage permission levels across systems can be readily customized based on specific business needs;