You should reset your Apple ID password ASAP and if you used the same email/password elsewhere – change it there too! Even if these hackers haven't gotten as many passwords as they say – they clearly obtained some and they're offering verifiable account info to prove it.
Original Post from Bitdefender:
#FridayFact: you should always have strong, hard-to-crack passwords for your accounts. And you should always ensure that your password is unique, and not being used on any other sites.