Over the weekend, a saga unfolded that should serve as a reminder to clean up your inbox and shore up your passwords regularly.

On Friday night, an unknown number of users were notified by Microsoft that its webmail client, Outlook.com, was hacked in what the company dubbed a months-long security breach, which was confirmed by TechCrunch on Saturday. The Redmond, Washington-based tech giant sent emails detailing the scope: Hackers could access subject lines, folder names, and contact lists but not email content or user passwords.

On Sunday, Microsoft admitted to Motherboard that roughly 6 percent of affected accounts did suffer hacks allowing access to email content. Motherboard also reported that the nature of the breach meant enterprise or business accounts were unaffected--only normal consumer accounts were hacked. Microsoft hasn't yet responded to a request for comment from Inc. regarding the extent of the attack.

Still, the episode is a valuable reminder for entrepreneurs to shore up their email security, as 70 percent of cyber attacks target small businesses. A recent Lifewire ranking listed Switzerland-based ProtonMail, a free encrypted email provider with an $8 per month business plan, as one of the world's most secure email services. For comparison, Google's cheapest G Suite plan is $6 per month.

There are plenty of resources online to protect yourself and your business from email scams, including free email systems tests from many internet security companies. Security experts also recommend setting clear conduct policies for all employees, especially regarding any personal devices they bring into the office.

Of course, the standard advice always applies: If you think your account has been breached, change your password. And if your account still gets hacked after that, ditch the account and start a new one.

You can't be too careful. Your livelihood could depend on it.