We have seen customers get Backup Exec files hit by RansomWare -
if it hits backup to disk data files (BKF and IMG folders) or the Deduplication storage and you do not have copies of Backup Sets on tape or some other un-affacted media location then you won't be able to restore
If it hits the catalog folders (which is most likely based on your description) or other files relating to Backup Exec then you should be able to restore given a number of manual steps depending on what is broken first. (re-catalog media, possibly even re-install BE and then recatalog etc)
You kind of really need to work out what is affected though - or even consider starting with a clean server and move the backup sets to that so that you are sure that the ransomware is not still around.