hackers getting into minecraft easily.

Put the summary of the bug you're having here
hackers getting into minecraft easily.
What I expected to happen was...:
Describe what you thought should happen here
make it harder for cracked acounts to be made or make it harder for hackers to get into servers via an ip
What actually happened was...:
Describe what happened here
a player called "Ribbit_the_Frog" joined a white listed server then left ( he was not white listed)
Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...