On this system we are not permitted to install any modules

I have seen that policy countless times. It's usually "for security reasons". My usual answer to the "admin" is along the lines in writing: "This is a new security problem created by your policy. These workarounds you are proposing are very insecure! Are you really sure you want it implemented this way? Are you taking the responsibility for it?"

Just make sure you CC a number of relevant people (like: your boss, the admin's boss, etc). So when the fit hits the shan, too many high level tie wearers are involved to make this a big affair that gets blamed solely on you. It usually gets swept under the rug, along with the results of all the other "informed decisions" made by middle management over the past year.