Last.Fm – Mar 22, 2012
On Mar 22, 2012 attack happened. The music website Last.fm was hacked and 43 million user accounts were exposed. Whilst Last.fm knew of an incident back in 2012, the scale of the hack was not known until the data was released publicly in September 2016. The breach included 37 million unique email addresses, usernames and passwords stored as unsalted MD5 hashes. On Sep 20, 2016 only breach discovered.