Yahoo's Sullivan says he's joining Facebook as its chief security officer

Yahoo's cybersecurity chief says he's heading to Facebook to become its chief security officer.

Alex Stamos said in a Facebook post that he will be joining the social networking company on Monday. He succeeds Joe Sullivan, who departed Facebook Inc. in April to head to Uber.

Stamos served as Yahoo Inc.'s chief information security officer for a little over a year, having started there in March 2014, according to his Linkedin account.

Shares of Facebook added 37 cents to $89.23 in Thursday premarket trading.