I have generated most of my wallets through brainwallet.org.But the address that got hacked was the only that I used to create a transaction via brainwallet.I don't remember my passphrase since I was just smashing my keyboard writing random characters for about 10-15 seconds it must have been at least 50(though I think it was more than 100) random nonsense characters.I then just copy the addresses and private keys to a notepad and forget the passphrase forever.I am almost sure it has to do nothing with the passphrase.