Alex Stamos, Yahoo's chief information security officer, announced on his Facebook page Wednesday that he's leaving to take a similar post at Facebook.
"The Internet has been an incredible force for connecting the world and giving individuals access to personal, educational and economic opportunities that are unprecedented in human history," Stamos wrote. "These benefits are not without risk, and it is the responsibility of our industry to build the safest, most trustworthy products possible."
He added: "This is why I am joining Facebook."
The post generated over 800 likes on the social media service he'll soon be working for.
Stamos had served as Yahoo's top cybersecurity officer and was with the company for a little over a year. He succeeds Joe Sullivan, who left Facebook in April to join ride-share startup Uber.