Crocker made money by offering to send commercial messages to accounts.

A New York hacker who used the alias Phastman on the hacking forum Darkode hijacked more than 77,000 Facebook users profiles and used them to send spam to their friends.

Computers were compromised when a user clicked on a link in a Facebook message sent by an already infected friend. The friend would then be infected with malware known as Slenfbot or Dolbot, which would then download Facebook Spreader making accounts vulnerable and accessible by the hacker.

Eric Crocker, 39, from Binghamton, New York was one of 70 people arrested (12 in the US) as part of Operation Shrouded Horizon. The operation has been labelled by the FBI as “the largest coordinated international law enforcement effort targeting an online cyber criminal forum”.

Crocker and other hackers using the Facebook Spreader tool earned $300 for every 10,000 computers they attacked by selling commercial messages which would be sent to infected users friends.

The U.S. Attorney’s Office in Pittsburgh said in a statement Crocker pleaded guilty to violating the CAN-SPAM Act; a federal law on violations of Internet communication.

He now potentially faces up to three years in prison, a $250,000 fine or both. He will be sentenced on 23 November.