Filter this response based on my being a pen tester, not a Unix/Linux admin - I'm much better at finding vulnerabilities and shortcomings than I am at coming up

Filter this response based on my being a pen tester, not a Unix/Linux admin - I'm much better at finding vulnerabilities and shortcomings than I am at coming up with a really good solution to them :). That's also why I can't give you a worthwhile answer about an auditing setup - I could tell you which ones I'm not super fond of, but I've never run the auditing side of things on Unix/Linux systems. The challenge I've run into with the group permission is that because there's only the owning group for the file/directory, there are basically two options: 1 - Leave the content owned by the primary group of the service account which also owns the file, and make support staff members of that group. This has the side effect of giving those support personnel access to just about everything else that group can get to, even if they don't need it. 2 - Create a new group that's just for delegating permissions for whatever content needs to be secured, and add both the service account and the users. This is analogous to using the new group as a quasi-ACL, IMO. It works, but quickly leads to group sprawl, and most of the Unix/Linux admins I've worked with are loathe to do it for this reason. A secondary challenge with #2 is that larger organizations will usually have group membership controlled by some sort of administrative team. So getting the group membership changed is a much bigger headache than the filesystem object owner modifying the ACL on their own content.