From the Wikipedia:

A typical configuration is a hardened Unix machine configured with SSH and a local firewall. A SSH connection is then made from the administrator's desktop to the Jump Server and SSH forwarding is used to access the target machine in the DMZ.

From this I would gather that a Jump Server is accessed through SSH, just like any other server.

Now, whether you have the appropriate and credentials to do so is another matter. And whether it is a good idea to allow a random script to access a highly sensitive server is a question that you need to take up with both your Boss and your Security Officer.