File sharing sites such as Dropbox make it very easy to share files. They also make it very easy to be hacked.
My first suggestion is: if you have data that is sensitive, be careful before putting it on a file sharing site such as this. If you do put it on a site like this, make sure you have a strong password that you change every 90 days.
Some file sharing services are starting to offer 2 factor authentications. If you have data that needs to be secure, you should enable 2 factor authentication.