Yahoo Resets Passwords After Mass Hack Data was stolen from third-party database, Yahoo says By Rob Quinn, Newser Staff Posted Jan 30, 2014 11:39 PM CST Updated Jan 31, 2014 12:10 AM CST 5 comments Comments This screen shot provided by Yahoo Inc., shows its upgraded email system. (AP Photo/Yahoo Inc.) (Newser) – More trouble for Yahoo:The company says an undisclosed number of passwords were stolen in a "coordinated effort to gain unauthorized access to Yahoo Mail accounts." The company doesn't say when the attack took place, but affected users are now being notified, PC World reports. In a blog post, a Yahoo spokesman says the usernames were probably stolen from a third-party database instead of from Yahoo's own systems. "We regret this has happened and want to assure our users that we take the security of their data very seriously," says the spokesman, who urges users to change passwords regularly and never use the same password for multiple sites. The passwords of affected users have been reset, so "if you’re trying to log in and Yahoo is asking you to change your password and verify your identity via SMS, this is probably why," TechCrunch notes.