I’ve spent a lot of time looking for the easiest way to unpack ISO image file under Linux without mounting it (it requires root privileges).
The solution you may find over the Internet describes various tools – one option is to install p7zip and p7zip-plugins (which is OK) or other custom tools which I wouldn’t like to depend on in my configuration.
However, there is not much information about bsdtar that is an excellent replacement of the common tar tool which also allows unpacking ISO images with:
$ bsdtar xvf image.iso