In February, Barbara Corcoran, founder of real estate brokerage firm Corcoran Group and judge on ABC's "Shark Tank," was nearly scammed out of $400,000.

"Scammers found their way to me in the most clever and simple way," she tells CNBC Make It

The scammers emailed Corcoran's bookkeeper pretending to be her assistant. The message contained an invoice supposedly authorized by her assistant to pay for an investment property in Europe that needed renovations. 

"The story was totally plausible because I invest in a lot of real estate and do a lot of renovations for a living," says Corcoran. 

However, the investment property it referred to was not real and Corcoran's assistant hadn't actually sent the email.

Corcoran became aware of the scam when her assistant was copied in an email from the bookkeeper about the wire transfer. The scammers had created a fake email address for her assistant by leaving out one letter of her name. Corcoran and her team realized the trick when her bookkeeper added her assistant to the conversation using her real email address.

"No one reads their email addresses that carefully that you see day in and day out, and the scammers knew it," says Corcoran. 

Thankfully, though the money was already gone from Corcoran's account, her bank in New York froze the money before it made its way to the scammers in China and she was able to get it all back. 

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This type of scam is called business email compromise (BEC) or email account compromise (EAC) by the Federal Bureau of Investigations. These scams happen when someone compromises businesses' email accounts in order to conduct unauthorized transfer or funds.

Last year, the FBI received 23,775 BEC complaints with losses adding up to more than $1.7 billion, according to the FBI's 2019 Internet Crime Report

In order to avoid becoming the latest victim of a scam, Corcoran says to always double check details like email addresses, which she plans to do from now on.

"It is as simple as that," she says. 

There are other ways to protect yourself from scammers:

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Disclosures: NBCUniversal and Comcast Ventures are investors in Acorns. CNBC owns the exclusive off-network cable rights to "Shark Tank."