Minecraft Server Chicken Exploit Fix
So I happened to encounter an interesting exploit last week on my Minecraft server. Basically had an area in the map which if you went anywhere near it, you would lag out so much, that it could crash the server. This was in a popular area, and therefore the server was crippled. I took the server off line, and investigated the problem on MC Edit. The map was laggy in MC Edit as well, but while it displayed some odd Entities located in the center of the effected area, it did not show anything else. Selecting the entire area, I analyzed it, and found that there were OVER 9000! Chickens located in the area... But I couldn't see them. I decided to try Removing all Entities, and that seems to have gotten rid of the chickens. But the odd Entities were still there and didn't come up as anything unusual if analyzed.
Okay, well, that is good enough I guess. So I saved the map and logged back into it on Single Player Minecraft to check it out. I was able to approach close enough that the chunk would draw, but then began to lag again heavily. I did notice a hole in the map. The hole was near the unusual entities, and while I couldn't see anything there, I did notice that the hole was odd in that it appeared to go all the way down to the bedrock. Water wasn't falling down it, but it was different in that you could see the blocks all the way down along the side.
So I headed back to MC Edit, and began to see some chickens as entities...
Again, I removed the entities, and again the odd entities were still there. About 8 blocks in all, which were not able to be deleted. Upon analysis, the odd entities again appeared as nothing unusual. There was one odd exception however. This time I was getting 2 'future blocks' listed in the block listing. Future Blocks? what?
I made a box around the effected area and decided to delete all the blocks and fill it with stone. I saved and returned to the game. Inside Minecraft, I was able to get a little closer, but the lag quickly accumulated. I was able to save after the lag became too over bearing, and went back into MC Edit. I analyzed the area and found no chickens, but I did find a bunch of feathers and 'Raw Chickens' centered around two spots within the stone. I then deleted the stone, but left a container one stone thick around the suspected effected area to catch and hold any future spawned chickens. Again I saved and loaded back into Minecraft.
In Minecraft I was able to get closer, but the lag was pretty bad. I saw no chickens, but saved and returned to MC Edit. Inside MC Edit I didn't see any chickens right away. It took 2 scans to find the chickens along the bottom of the container. Finally they showed up as the red entity squares that their supposed to. I removed them, and again deleted all the blocks in the effected area, and filled with stone. I saved again and went back into Minecraft, then saved and returned to MC Edit. Again I saw chicken feathers, and raw chickens located around two specific points within the stone. These must be the spawn points!
I then created a narrow pathway in the stone and connected the two points, creating small chambers around each point. I made a small hallway to the exit, and saved and returned to Minecraft. I was able to move my avatar into the hallway I created but the lag grew too intense to go much further. Again saved the game and returned to MC Edit. Cleared entities, and returned to Minecraft. This time, I was able to run up towards the spawn point. As I approached, I saw chickens literally pouring across the floor. I got into the actual chamber and then saved and returned to MC Edit.
This is when I found out how to get rid of this. Since I was literally standing beside this invisible 'Future Block', there was no escaping for this mystery block. Back in MC Edit, I again filled the area with stone, filling in my hallways. Deleted blocks and cleared entities, saved and returned to Minecraft. And there I stood. Stuck inside a stone sarcophagus. Being in creative, I simply clicked to remove the blocks around me. I believe it was the actual act of removing the blocks in the area in game which removed this future block spawn object. I created a room in game, large enough to contain the invisible spawn item from where I remember it being, and waited. Nothing! Lag wasn't as bad, but was still increasing. I still had one more spawn to take care of.
I made my way towards the other spawn and did a similar thing. Then after saving and hopping between MC Edit and Minecraft a few times I confirmed that the chicken spawners were no longer there. Phew! All in all, it took about 3 hours.
Now, why did this happen?
I can only speculate that this was a malicious attack by a gaming clan of trolls.
The following people are believed to be involved: