BlueHens CTF 2021: Minecraft: Mixed Columns

This is from the BlueHensCTF 2021.

For this challenge, We are given the following information and links:

Here is the mc86 Intro:

/give @p minecraft:written_book{title:"Init CPU",author:"UD Cyberscholars",generation:0,pages:[
"{\"text\":\"Click Here First\\n\",\"color\":\"dark_green\",\"bold\":true,\"underlined\":true,\"hoverEvent\":{\"action\":\"show_text\",\"value\":\"Creating RAM\"},\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/setblock ~1 ~ ~ minecraft:lime_shulker_box\"},
\"extra\":[
{\"text\":\"Click Here Second\\n\",\"color\":\"dark_green\",\"bold\":true,\"underlined\":true,\"hoverEvent\":{\"action\":\"show_text\",\"value\":\"Start Timing Belt\"},\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/setblock ~2 ~1 ~ minecraft:command_block[facing=up]{powered:0b,Command:\\\"setblock ~ ~-1 ~ air\\\"}\"}},
{\"text\":\"Click Here Third\\n\",\"color\":\"dark_green\",\"bold\":true,\"underlined\":true,\"hoverEvent\":{\"action\":\"show_text\",\"value\":\"Finishing Timing Belt\"},\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/setblock ~2 ~2 ~ minecraft:chain_command_block[facing=up]{powered:0b,auto:1b,conditionMet:0b,Command:\\\"execute if data block ~-1 ~-2 ~ Items[0].tag.pages[0] run setblock ~ ~-2 ~ redstone_block\\\"}\"}},
{\"text\":\"Click Here Fourth\\n\",\"color\":\"dark_green\",\"bold\":true,\"underlined\":true,\"hoverEvent\":{\"action\":\"show_text\",\"value\":\"Start CPU\"},\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/setblock ~3 ~ ~ minecraft:command_block[facing=east]{powered:0b,Command:\\\"data modify block ~2 ~ ~ Command set from block ~-2 ~ ~ Items[0].tag.pages[0]\\\"}\"}},
{\"text\":\"Click Here Fifth\\n\",\"color\":\"dark_green\",\"bold\":true,\"underlined\":true,\"hoverEvent\":{\"action\":\"show_text\",\"value\":\"Finishing CPU\"},\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/setblock ~4 ~ ~ minecraft:chain_command_block[facing=east]{powered:0b,auto:1b,conditionMet:0b,Command:\\\"data remove block ~-3 ~ ~ Items[0].tag.pages[0]\\\"}\"}},
{\"text\":\"Click Here Sixth\\n\",\"color\":\"dark_green\",\"bold\":true,\"underlined\":true,\"hoverEvent\":{\"action\":\"show_text\",\"value\":\"Placing ALU\"},\"clickEvent\":{\"action\":\"run_command\",\"value\":\"/setblock ~5 ~ ~ minecraft:chain_command_block[facing=east]{powered:0b,auto:1b,conditionMet:0b}\"}}]}"]} 1

Finally, here is the challenge source code:

/give @p writable_book{pages:["/clone ~-4 ~ ~ ~ ~2 ~ ~-4 ~ ~2","/clone ~-4 ~ ~ ~ ~2 ~ ~-4 ~ ~4","/clone ~-4 ~ ~ ~ ~2 ~ ~-4 ~ ~6","/clone ~-4 ~ ~ ~ ~2 ~ ~-4 ~ ~8","/clone ~-4 ~ ~ ~ ~2 ~ ~-4 ~ ~10","/clone ~-4 ~ ~ ~ ~2 ~ ~-4 ~ ~12", "/give @p writable_book{pages:[\"/setblock ~5 ~13 ~ yellow_banner[rotation=4]{Patterns:[{Pattern:\\\"cbo\\\",Color:11},{Pattern:\\\"vhr\\\",Color:11},{Pattern:\\\"bo\\\",Color:11},{Pattern:\\\"mr\\\",Color:11}]} destroy\",\"/setblock ~5 ~10 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~7 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"bo\\\",Color:4},{Pattern:\\\"rud\\\",Color:11},{Pattern:\\\"ld\\\",Color:11}]} destroy\",\"/setblock ~5 ~4 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"mr\\\",Color:11},{Pattern:\\\"drs\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\"]}","/give @p writable_book{pages:[\"/setblock ~5 ~13 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"dls\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~10 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"mr\\\",Color:11},{Pattern:\\\"drs\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~7 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"ms\\\",Color:11},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~4 ~ yellow_banner[rotation=4]{Patterns:[{Pattern:\\\"cbo\\\",Color:11},{Pattern:\\\"vh\\\",Color:11},{Pattern:\\\"mr\\\",Color:11}]} destroy\"]}","/give @p writable_book{pages:[\"/setblock ~5 ~13 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"ms\\\",Color:11},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~10 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"tt\\\",Color:11},{Pattern:\\\"drs\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~7 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"dls\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~4 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\"]}","/give @p writable_book{pages:[\"/setblock ~5 ~13 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ms\\\",Color:4},{Pattern:\\\"rs\\\",Color:11},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~10 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"hhb\\\",Color:11},{Pattern:\\\"ms\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~7 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"ms\\\",Color:4},{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~4 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"tt\\\",Color:11},{Pattern:\\\"drs\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\"]}","/give @p writable_book{pages:[\"/setblock ~5 ~13 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"cbo\\\",Color:11},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~10 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"hhb\\\",Color:11},{Pattern:\\\"ms\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~7 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"bo\\\",Color:4},{Pattern:\\\"rud\\\",Color:11},{Pattern:\\\"ld\\\",Color:11}]} destroy\",\"/setblock ~5 ~4 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\"]}","/give @p writable_book{pages:[\"/setblock ~5 ~13 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"cs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~10 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"mr\\\",Color:11},{Pattern:\\\"drs\\\",Color:4},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~7 ~ yellow_banner[rotation=4]{Patterns:[{Pattern:\\\"ts\\\",Color:11},{Pattern:\\\"bs\\\",Color:11},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~4 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"tt\\\",Color:4},{Pattern:\\\"tts\\\",Color:11},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\"]}","/give @p writable_book{pages:[\"/setblock ~5 ~13 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~10 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"hh\\\",Color:4},{Pattern:\\\"cs\\\",Color:11},{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"drs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~7 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"ms\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\",\"/setblock ~5 ~4 ~ blue_banner[rotation=4]{Patterns:[{Pattern:\\\"ts\\\",Color:4},{Pattern:\\\"bs\\\",Color:4},{Pattern:\\\"rs\\\",Color:4},{Pattern:\\\"ls\\\",Color:4},{Pattern:\\\"bo\\\",Color:11}]} destroy\"]}"]}

As recommended by the challenge text, I got the latest Minecraft Java Launcher and launched a world:

I followed the YouTube video and gave myself a command block, placed it with a button on it, and posted the mc86 initcode:

I clicked the button and received an enchanted book:

I followed the instructions and clicked each of the six links to generate my mc86 computer in my world:

Next, following the YouTube video, I pasted the challenge source code into the command block I created earlier and click the button:

This gave me a 13 page book and quill:

I placed a button in the mc86 computer (as directed in the YouTube video) and and clicked it to run the challenge program:

This generated 6 new mc86 computers and gave me 7 new book and quills. Looking at these new books, I see that they are just a few ages each, different, and they generate banners:

I currently have 7 mc86 computers and 7 new books, so I place each of the books into the different computers, add buttons to them, and then execute the programs.

This generated 7 columns of banners in the sky:

I see that the top row of each contains what I would expect the beginning of the flag to be (UDCTF{) plus a 7.

I use my high-tech Microsoft Paint program to edit a screenshot by rearranging the columns so that the top row spells out UDCTF{7

Running down the characters gives me the flag:

UDCTF{7R4NSP0S3_7HE_C0LUMNS}

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