As in the HDP 2.4 sandbox VM, the 2.5 VM tries to do a git fetch from github for some tutorials. When SSH is blocked at the firewall (for security reasons, ssh allows reverse port forwards, etc) the boot sequence hangs indefinitely. To get the sandbox to boot I needed to find its IP, ssh into it as root, locate the script running the git fetch and comment out the related entries to be able to boot the sandbox VM.
Is this is a known issue? Is it worth submitting a bug to JIRA?
I haven't found evidence of this being a known issue, but I'd certainly suggest filing a JIRA as this will cause a bad experience within many corperate environments that block 22.