In general, you can copy the contents of the Knowledge base site easily with the mouse selection and Ctrl+C (or) alternative copy action. In confidential documentation, you would want to restrict the readers from copying the content. You can implement the below solution to restrict readers from copying the content.

By implementing the below solution, the readers can still select the content and perform a copy action (i.e., they can perform mouse selection and press Ctrl +C or perform any copy action). However, the content will not be copied.

Solution

1. Go to Settings -> Knowledge base site -> Custom CSS & JavaScript, and Custom JavaScript

2. Paste the below snippet in the window

$(document).ready(function(){
$('.content_block').bind("cut copy paste",function(e) {
e.preventDefault();
});
});

3. Click Save