I don't think a minecraft account could be stolen without your login info, but hackers can pose as you and make people think whatever problem was caused was caused by you. This happened to me on one occasion in which I was trying to help someone set up a server and had me banned because his server records logged that I had done the damage in which I will assure you I did not nor did anyone else with use of my account directly.
This was a while ago and I don't know if the problem still persists, however they can't take away access to the account from you without login info.