There isn't a Bitcoin account per se. There's a bitcoin wallet, it's available in digital and hardware versions.

Once you create a wallet, you get a private and public keys. Public key is used by others to send bitcoins to you. Private key is used by you only to send bitcoin to others.

So, if someone was able to obtain your private key, you are hacked.

It's very common that hackers tend to search for bitcoin wallet keys—private key—once they compromise a system.