Mac – Security problem if Mac Os X file sharing permissions for “everybody” is set to read-only

The hard drive I installed the fresh copy of OS X 10.9.4 completely died last week. I suspect that this hard drive failure was unrelated to the issues, but when I re-installed OS X again and went to add the share drives, everything worked as normal.

I suspect that this is an obscure bug, but if you come across this issue, a reinstall may fix it, as this worked for me.

No. Admin accounts can modify any ACL or permission you make to keep them out.

• Admin = root on OS X

I would consider placing the files on a file server and control access over file sharing (where your account is the only admin) or remove admin permissions from the accounts that cannot be trusted to not be malicious or careless.