It was discovered that the Unitrends Backup (UB) before 10.1.0 user interface was exposed to an authentication bypass, which then could allow an unauthenticated user to inject arbitrary commands into its /api/hosts parameters using backquotes.
Resolution is to upgrade to Unitrends release 10.1.0 or later.
How to enable the release 10.1 upgrade
LINK TO ADVISORIES
[Discoverers] Benny Husted, Cale Smith, Jared Arave