The Attachment Security module for Odoo 16 is a custom security tool developed by Lucidbrainz that controls who can access and delete file attachments in the system. The module extends Odoo's attachment model to ensure that only the user who uploaded a file can delete it, preventing unauthorized deletion of important documents. It adds a visibility check mechanism to determine whether attachments should be shown to specific users and includes an administrative checkbox on user profiles to grant special deletion permissions. The module depends on the base and mail modules and provides read-only access to all users by default through security rules, while deletion rights remain restricted to the attachment creator. However, the current implementation has several technical issues including duplicate field definitions and incomplete permission integrations that need refinement for optimal functionality.