One of the most effective steps you can take to protect your cloud account is to make sure you are using two-step verification. In addition, always be sure you know exactly whom you are sharing files with. It is very easy to accidentally share your files with the entire Internet when you think you are only sharing them with specific individuals.
See our page on Multi-factor Authentication for information on MFA.
See our tips page for using Box for more information on sharing.
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Source: SANS Security Awareness Tip of the Day