An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. The privileged vaultServer could be leveraged to create arbitrary writable files, leading to privilege escalation.
https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2
https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1