This libreoffice exploit is hilarious:
Just open that spreadsheet, add files you want to copy from the system, an url where to send the files to and upload to some service running libreoffice under the hood (more than you think :)
yes it runs without user-interaction.
yes commandline pdf-conversion is enough.
you can also just send it to someone if he opens it on libreoffice your spreedsheet can copy files..