I can't install any modules on this box so Net::SSH is out of the question.

That in itself is not necessarily true. You can just make a directory with all the required files (for example a copy of your development box perl library), and use something like this:

BEGIN {
    unshift @INC, "/home/username/src/sitelib/";
}
use Net::SSH;
[download]

That said, if you can't install the correct software to do your work, your company policy and/or server setup is incorrect in my opinion.