- Facebook shares tumbled Friday after the social-media network disclosed that it was hacked earlier this week.
- The flaw, which was discovered on Tuesday, allowed hackers to access nearly 50 million users' accounts, Facebook said.
- A Taiwanese hacker, Chang Chi-yuan, announced Wednesday that he found bugs on Facebook and would live stream how to use the flaw and delete CEO Mark Zuckerberg's Facebook account. He backed down on Friday.
- Watch Facebook shares trade in real time here.
Facebook shares dropped more than 3% Friday after the company disclosed that hackers took advantage of a security issue to attack its systems, impacting almost 50 million accounts.
"Our investigation is still in its early stages," Facebook's VP of Product Management Guy Rosen said in a statement, adding that it's not yet clear who was behind the attack.
"But it's clear that attackers exploited a vulnerability in Facebook's code that impacted 'View As', a feature that lets people see what their own profile looks like to someone else," he said. "This allowed them to steal Facebook access tokens which they could then use to take over people's accounts."
Shares have been under pressure since Thursday, after a Taiwanese hacker, Chang Chi-yuan, announced that he found bugs in Facebook's code and would live stream how to use the flaw to delete CEO Mark Zuckerberg's Facebook account.
"Live streaming the deletion of FB founder Zuck's account," Chang posted on his Facebook page on Wednesday, "Scheduled to be live."
But on Friday, he told Bloomberg that he had canceled his plans and that he would show proof once he received a bounty from Facebook.
Facebook shares are down 10% this year.
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