For the owners of the affected accounts, and of another 40 million that Facebook considered at risk, the first order of business may be a simple one: sign back into the app. Facebook logged everyone out of all 90 million accounts in order to reset digital keys the hackers had stolen — keys normally used to keep users logged in, but which could also give outsiders full control of the compromised accounts.
Next up is the waiting game, as Facebook continues its investigation and users scan for notifications that their accounts were targeted by the hackers.
What Facebook knows so far is that hackers got access to the 50 million accounts by exploiting three distinct bugs in Facebook’s code that allowed them to steal those digital keys, technically known as “access tokens.” The company says it has fixed the bugs.
Users don’t need to change their Facebook passwords, it said, although security experts say it couldn’t hurt to do so.
Facebook, however, doesn’t know who was behind the attacks or where they’re based. In a call with reporters, CEO Mark Zuckerberg — whose own account was compromised — said that attackers would have had the ability to view private messages or post on someone’s account, but there’s no sign that they did.
“We do not yet know if any of the accounts were actually misused,” Zuckerberg said.