Hypixel sends sometimes a magic packet with id 0xaa
Hypixel sends sometimes a magic packet, see the description below (Bug report to hypixel):
Minecraft account
Bixilon
Minecraft version
1.8.9
Modifications
Minosoft
Server IP
mc.hypixel.net
Server number
Independent
Map
Independent
Minigame
Other
Description
Dear Hypixel Team,
i found another protocol bug, that lets my own client (https://gitlab.bixilon.de/bixilon/minosoft) throw an fatal exception.
This bug is NOT version dependent and it happens BEFORE connecting to the server.
The normal ping request should look like this:
C -> S: 0x00 Handshake
C -> S: 0x00 Status Request
S -> C: 0x00 Status Response
C -> S: 0x01 Status Ping Request
S -> C: 0x01 Status Ping Response (pong)
That's always possible, so that's not the problem (just want to explain it, so my bug report is comprehensible and does not get instantly closed).
The problem is, that sometimes after the pong packet, I can receive another mysterious packet with the id 0xAA.
It looks like this: "GHsiZXh0cmEiOlsiIl0sInRleHQiOiIifQ==" (Base64 encoded) in hex it is this:
1b aa 01 18 7b 22 65 78 74 72 61 22 3a 5b 22 22 5d 2c 22 74 65 78 74 22 3a 22 22 7d
0x1b is the length, 0xaa is the packet id, 0x18 is a magic byte (could be a VarInt) and the rest of the data is a string that tells me: "{"extra":[""],"text":""}". Looks like a blank text component.
This is not valid and as far as I can tell, it also brings an exception in the original minecraft client ("Could not connect to server").
I am reporting it, because it is (obviously) not my or mojangs fault. So I assume it is your fault, indeed I have no clue, what this package should do. I have not planned to fix this in my client, it is a fatal exception, it could mean anything.
I also asked on the #mcdevs IRC if anybody knows if this is an undocumented special feature, pokechu22 replied, that he also has no clue.
Reproduce:
I can only see this packet rarely, it won't be sent with every ping. A possibility is to just spam ping packets (always open a new connection), there is a chance to receive it (aka. Just hold down F5 and have a look in the console). Good luck :)
I hope you fix it soon, it is kind of annoying.
Thank you
Moritz Zwerger
I also opened an issue in my own project to track this issue: https://gitlab.bixilon.de/bixilon/minosoft/-/issues/10
I'll paste your answer there, once I receive one (name censored of course). If you have a problem with that, let me know:=)
I will keep this issue up to date
Edited by Moritz Zwerger