Donít permit any unowned file. Unowned files may also be an indication that an intruder has accessed your system. If you find unowned file or directory on your system, verify its integrity,
and if all looks fine, give it an owner name. Some time you may uninstall a program and get an unowned file or directory related to this software; in this case you can remove the file or directory

To locate files on your system that do not have an owner, use the following command:

[root:~]# find / -nouser -o -nogroup