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Challenge Minecraft???
I’ve placed a lectern near this village, and there’s a book here - I definitely did not hide the Flag here
Objective
Find the lectern location shown in the image. Once you get there, you’ll definitely be able to find the Flag… maybe?
Facing Direction
I’m facing southeast.
Coordinate Range
- X: 100000 ~ 150000
- Y: 60 ~ 75
- Z: -1000 ~ 1000
You’re free to wander around and survive on my server, but you must not grief the server or interfere with other players’ progress while solving.
Server Connection Info
- Version:
Java 1.21.11 - IP:
mc.pg72.tw - Password:
THJCC_3rd_Summer_CTF
If you’ve already figured out some of the coordinates, I don’t think you need to try them one by one - I believe you’ll know what to do with them :D!
Rule: No plugins, cheat clients, mods, or automation tools are allowed. Violations result in an immediate ban.
Challenge Design Inspiration:
The idea for this challenge came from this video:
Simply put, when Minecraft generates terrain, it has a seed that can determine which way each block faces (grass, stone, etc.). This adds variety and keeps everything from looking too uniform and boring.
That made me think I could use this feature to make a CTF challenge. In the end, I put it in Forensics (that counts as digital forensics, right? :thinking:)
Solution:
Method 1
First, analyze the image, paying particular attention to how the grass blocks are generated. You can identify the orientation of each block:
Install the Manual texture rotations resource pack, then recreate the terrain in the photo on a blank map using specific blocks (for example, light green glazed terracotta for grass):
After recreating it, switch to the Textures to numbers resource pack, and you will see a bunch of black blocks and numbers.
Next, open this website:
Enter the relative coordinates. Here is the data you can import:
110 collapsed lines
[ { "pos": { "x": 0, "y": 0, "z": -1 }, "rotation": 0, "side": false }, { "pos": { "x": -1, "y": 0, "z": -1 }, "rotation": 2, "side": false }, { "pos": { "x": -1, "y": 0, "z": 0 }, "rotation": 3, "side": false }, { "pos": { "x": -2, "y": 0, "z": 1 }, "rotation": 3, "side": false }, { "pos": { "x": -3, "y": 1, "z": 1 }, "rotation": 0, "side": false }, { "pos": { "x": -3, "y": 1, "z": 0 }, "rotation": 1, "side": false }, { "pos": { "x": -3, "y": 1, "z": -1 }, "rotation": 0, "side": false }, { "pos": { "x": -3, "y": 2, "z": -2 }, "rotation": 3, "side": false }, { "pos": { "x": -2, "y": 1, "z": -2 }, "rotation": 3, "side": false }, { "pos": { "x": -1, "y": 1, "z": -2 }, "rotation": 2, "side": false }, { "pos": { "x": 0, "y": 1, "z": -3 }, "rotation": 1, "side": false }, { "pos": { "x": 1, "y": 1, "z": -4 }, "rotation": 2, "side": false }]
After importing the data, select the version and enter the limits described in the challenge into the fields. Then you can brute-force some results:
20 collapsed lines
100487, 61, -69100839, 63, -962100929, 65, 655102309, 65, 893102597, 72, 600102957, 60, 467104694, 71, -382105235, 73, 666106664, 75, -833107175, 62, -968108539, 65, -251109007, 64, -275111078, 70, -567111095, 64, -641111505, 75, 190111621, 72, -676112598, 60, 72112597, 72, 746113914, 67, 736114330, 61, 90114514, 72, 81075 collapsed lines
116394, 67, 412116546, 62, -936116914, 72, -414117346, 71, -980117446, 68, 175117516, 69, -635117718, 66, -781117873, 65, -547118466, 66, 911118705, 66, 931121658, 74, -726121780, 65, -972122226, 62, -671122326, 65, 630122329, 74, 926122590, 70, 57123085, 66, -949124372, 61, -267124435, 75, -833124490, 68, 770124510, 61, -426125368, 61, 356126032, 62, -686126732, 72, 56127139, 65, 216128696, 75, 113128786, 70, -348129062, 69, -517130169, 66, 785130190, 62, 407130259, 61, 862130836, 74, -634130895, 72, -564130979, 71, 120131230, 71, -316131920, 63, 177132368, 71, -49132577, 61, -437133408, 70, -685133517, 65, 74134227, 63, 321135657, 64, 114135661, 62, -748135769, 69, -673135919, 64, 31135952, 67, 890136500, 74, -802136934, 67, 476138271, 62, 679138775, 67, -976139086, 62, 460140178, 67, 185141305, 68, -466143029, 60, 230143066, 73, 720143084, 69, 604143140, 66, 90143575, 64, -875143656, 72, 620143814, 71, 679144843, 63, 671144869, 75, -166145111, 61, 861145311, 66, 318145353, 75, 66145787, 68, -887146533, 64, 287147247, 73, -728147575, 71, 244148474, 68, 634149209, 71, -58149318, 62, 445149563, 71, 926149609, 71, 536149627, 74, 228Among these results, one particular coordinate, 114514, 72, 810, is very stinky lol. So just TP there and read the book to find the Flag!
Flag:THJCC{M1n3Cr@f7_15_S0_FuNnY
}
Method 2
Walk or run around one block at a time, slowly and patiently, and you can find the answer :D
Afterword:
I actually spent a lot of time designing this challenge, but I still could not stop some kids from messing around—blowing up the map, leaking the coordinates, maliciously killing participants to keep them from solving it, etc. In the end, we had to take the whole challenge down.
Honestly, it was pretty sad. This really was a fun CTF challenge you could experience in everyday life.
Of course, these problems were not the participants’ fault; the challenge simply was not designed well enough. Better designs could have included instances, Adventure Mode, dynamic coordinates/Flags, etc. These could have effectively prevented some of those things from happening. I just did not have enough experience to think of them QwQ
I will also provide the world file for you to download and play with. I hope you like this challenge!