We urge everyone in the Minecraft community to change their Minecraft.net passwords ASAP. Please read below for tips on how to create a better password before doing so.
It recently came to our attention that a list of Minecraft account names and passwords were made freely available on the internet. We believe this list consists of information collected by a group of malicious users from a well known "griefing team". How the information in this list was obtained is not sure, but we suspect they collected them through the use of hacked clients that pretend to only give you extra features like flying or seeing through blocks but actually send your account information to the creators as well.
The first thing we did when we acquired this information was to inform Mojang of this crisis, however, we feel we can do a bit more for the community while we wait for them to handle the situation properly as we've learned that there's a high possibility that the griefing team is aware that their list has been made public. As such, we are going to be re-emptively anning compromised accounts with an informative reason.
If there is ONE thing you read in this announcement, it should be this: we urge everyone to go and change their passwords NOW, keeping in mind the following tips on creating better passwords:
Passwords should not contain words found in the dictionary
Passwords should contain a mixture of upper and lowercase characters.
Passwords should contain a mixture of letters and numbers.
Passwords should contain punctuation characters and symbols such as: % & + - = #.
Choose a password you can remember but don't make it too easy.
Passwords should be at LEAST 8 characters in length, but 14 or more is preferable.
Please help us by sharing this information with everyone you know and getting them to change their Minecraft.net passwords.