Permissions to edit an attachment in a list

Question

I want people to be able to edit an attachment in a List item, but NOT be able to delete or add an attachment. Thus, I set up the below customized permission (I have SP 2013 Enterprise), but individuals are able to add a document with the below Customized permission. What is wrong ? Note within the list I turned off inherited permissions and give unique permissions.

List Permissions (Below is what I checked) Edit Items View Items Open Items View Versions Create Alerts View Application Pages

Site Permissions Browse Directories Use Self Service Site Creation View Pages Browse User Information Use Remote Interfaces Use Client Integration Features Open Edit Personal User Information

Personal Permissions Manage Personal Views Add/Remove Personal Web Parts Update Personal Web Parts

Answer 1

Attachments are part of the list item, you have given users with Edit items permission, its nothing but making changes to the items. Internally editing the items means making changes to the content DB, so the same permission is needed to create an item and delete an item, that's the reason why the users are able to add and delete items from that list.

I don't think that SharePoint gives permission level to only edit the attachments in a list item.