Facebook has an estimated 800 million users and receives over a billion login attempts every day, the Daily Mail said.
The hackers try to steal user information, spread frauds or send bogus offers and malicious messages, and also try to sell counterfeit goods to members' friends.
Facebook recently issued a security announcement promoting its new "Trusted Friends" password restoration technique.
Many of the hackers are caught by additional authentication questions, such as asking users to identify friends in pictures.
"At least 600,000 times a day, we stop a bad guy from getting access to an account even though he has guessed, phished, or stolen the login and password of an account. This is something we're very proud of," Facebook spokesman Barry Schnitt was quoted as saying.