Need help to set correct permissions once and for all to prevent spam being sent

My site – philipus.com – lives on a server of Bigbluehost. Several times in the past year folders on my site have been used to send spam and BBH has suspended the site.

Each time I have – with minimal assistance from BBH support – tried to find the offending folders and correct the permissions. I should add that I have not changed any permissions so I have no idea why the permissions could be wrong.

I would like to prevent this from happening in the future and am now looking for a way to ensure – once and for all – that permissions are correct. Is there an automated way to set permissions correctly on the entire site? If not, what can I do to sort this out?

Thanks a million for any help (and please keep in mind I am not technologically very advanced)

Best
philip