A Practical Guide to Red HatВ® LinuxВ®: Fedoraв„ў Core and Red Hat Enterprise Linux (3rd Edition)

The traditional UNIX permission system allows three permissions to be assigned to each file: controlling access by the owner, by a single group, and by everyone else. ACLs provide much finer-grained access control. In theory, ACLs can increase security. However, they make setting correct permissions more complicated, which may encourage administrators to establish weaker controls than they should.