Kaseya Virtual System Administrator (VSA) 7.x before 7.0.0.33, 8.x before 8.0.0.23, 9.0 before 9.0.0.19, and 9.1 before 9.1.0.9 does not properly require authentication, which allows remote attackers to bypass authentication and (1) add an administrative account via crafted request to LocalAuth/setAccount.aspx or (2) write to and execute arbitrary files via a full pathname in the PathData parameter to ConfigTab/uploader.aspx.