Facebook is probing a series of security failures in which employees built applications that logged unencrypted password data for Facebook users and stored it in plain text on internal company servers. Facebook says an ongoing investigation has so far found no indication that employees have abused access to this data. The social network is still trying to determine how many passwords were exposed and for how long, but so far the inquiry has uncovered archives with plain text user passwords dating back to 2012. Facebook plans to notify affected users, but no password resets would be required.”]