(adsbygoogle = window.adsbygoogle || []).push({}); Ok so, this has been used by a lot of the high-end griefing teams for awhile to grief bigger servers. This is also the reason why everyone thinks ForceOP is real, since it was before, and it is now, and it is going to be further down the line.

This tutorial was not written by me, though it explains about the much I want to say, as I rather not give out a client with this already implemented, with that said only users who know java and can make a client are able to use this, Enjoy




First of all, let me explain how this exploit works. When you connect to a Minecraft server, you send a handshake packet (Packet2ClientProtocol) that contains the username you want to connect with. The server then goes and tries to authenticate that with the Minecraft auth servers. In that time that it is authenticating, you can send another handshake to the server with a new username of your choice. The server doesn't authenticate this second username, as it has already started authenticating the first. This tricks the server into using the valid response from the first handshake on the second handshake. Basically, it lets you switch usernames, without authenticating the second username.

This is simple enough to do: Just find where your client sends the handshake packet, add a delay after that, and then send a second handshake packet, with your new username.

Code:

Go to ThreadConnectToServer.java. Under the run() function, find where the Packet2ClientProtocol is sent.

Under that, add a delay and then send a second packet, with your changed username:
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Now to get the timing correct. If you get a response from the server saying "Invalid client reply", you need a longer delay.

Likewise, if you get a response saying "Failed to verify username", you need a longer delay.

If you get a response saying "Protocol error, unexpected packet", you need a shorter delay.



Now, if you can get the timing correct, you will see your client connect to the server, but then you will lose the connecting and get a connection reset error. As far as I can tell, this is because the server is sending back two ServerAuthData packets. This confuses the client.

The way to fix this is to not accept the response from second ServerAuthData packet sent from the server (the one that comes in return to our fake handshake).

Code:

Go to NetClientHandler.java.


Create a boolean:
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In each of the constructors for NetClientHandler:
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Set firstConnection to true:
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Now under the handleServerAuthData() method, add this at the beginning:
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Have fun destroying as many servers as you can while it's not 100% patched.[/COLOR]

k TANX!!!
BAI

I DONT EVEN PLAY MINECRAFT
whoops caps was locked

good job V, good job
i still dont play mincrap

This still works on a lot of smallers servers due to them not being experienced enough.

Another ForceOP is known to smaller private groups and it will be hopefully kept that way, if it starts to be leaked i'll make another thread and write out the full tut unlike I did with this one.

On another note the newer ForceOP only works with certain servers who have other plugins / don't have some plugins.