After killing the hung apt process I ran dpkg --configure -a , which hung again. Killing the hung dpkg process and running dpkg --configure -a again allowed the package installation to complete but resulted in a broken module:
$ VirtualBox WARNING: The character device /dev/vboxdrv does not exist. Please install the virtualbox-dkms package and the appropriate headers, most likely linux-headers-generic. You will not be able to start VMs until this problem is fixed. $ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1775672 Title: virtualbox-dkms installation hangs in 18.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/virtualbox/+bug/1775672/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs