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| <html> | ||
| <head> | ||
| <title>Binary Golf Grand Prix</title> | ||
| <meta charset="utf-8"> | ||
| <style> | ||
| @font-face { font-family: "unifont"; src: url("/unifont.woff") format('woff'); } | ||
| body { color: #d9d9d9; background-color: #0c0d10; } | ||
| pre { font-family: "unifont", "Lucida Console", monospace, Monaco; font-size: 16px; line-height: 1.0; } | ||
| a { color: #93f1ff; text-decoration: none; } | ||
| w { color: white; } | ||
| k { color: #ff93f1; } | ||
| l { color: #f1ff93; } | ||
| r { color: #fa4d57; } | ||
| </style> | ||
| </head> | ||
| <body> | ||
| <div style="display: inline-block; text-align: left;"><pre> | ||
| <k>───<w> Binary Golf Grand Prix 1 </w>───────────────────────────────────────────────<w>//</w>──</k> | ||
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| Welcome to the Binary Golf Grand Prix! This is a challenge for people who like | ||
| to craft tiny binaries. | ||
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| There have been a few CTF challenges involving binary golf, but it is sadly a | ||
| dying art outside of the demoscene and some virus writing circles. | ||
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| Binary Golf is similar to Code Golf, where the purpose is to program something | ||
| in as few instructions as possible. It takes it a step further and challenges | ||
| people to create the smallest possible binary file as well. | ||
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| The goal of the Binary Golf Grand Prix is to challenge programmers to make the | ||
| smallest possible binary that fits within certain constraints. | ||
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| For more info on Binary Golf, here are some resources: | ||
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| - <a href="https://www.muppetlabs.com/~breadbox/software/tiny/teensy.html">A Whirlwind Tutorial on Creating Really Teensy ELF Executables for Linux</a> | ||
| - Elf Binary Mangling Parts <a href="https://n0.lol/ebm/1.html">1</a>, <a href="https://n0.lol/ebm/2.html">2</a>, and <a href="https://n0.lol/ebm/3.html">3</a> | ||
| - <a href="http://www.phreedom.org/research/tinype/">Tiny PE</a> | ||
| - <a href="https://n0.lol/a/pemangle.html">Modern PE Mangling</a> | ||
| - <a href="https://codegolf.stackexchange.com/questions/102471/smallest-possible-runnable-mach-o-executable">Tiny Mach-o</a> | ||
| - <a href="https://www.youtube.com/watch?v=VLmrsfSE-tA">Adventures in Binary Golf - AirGap2020</a> | ||
| - <a href="https://www.pimzero.com/2020/04/19/golf_so.html">golf.so (136 bytes)</a> | ||
| - <a href="https://saarsec.rocks/2020/05/14/golf.so.html">golf.so (163 bytes)</a> | ||
| - <a href="http://www.sizecoding.org/wiki/Main_Page">SizeCoding Wiki</a> | ||
| - <a href="https://github.com/mathiasbynens/small">small: Smallest possible syntactically valid files of different types</a> | ||
| - <a href="http://www.sizecoding.org/wiki/M8trix_8b">m8trix (8 byte COM file demo)</a> | ||
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| <k>───<w> The Challenge </w>──────────────────────────────────────────────────────────<w>//</w>──</k> | ||
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| The inaugural challenge of the BGGP is to create an <a href="https://en.wikipedia.org/wiki/Ambigram">Ambigram</a> binary. Ambigrams | ||
| are essentially calligraphy that is read differently or the same depending on | ||
| how you look at it. In particular, we'll be focusing on "rotational" ambigrams, | ||
| which are read the same when you rotate them 180 degrees. | ||
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| This challenge was inspired by <a href="https://twitter.com/0xdade/status/1274100140135964672">@0xdade</a> | ||
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| The binary you will craft will be the same executable when flipped backwards. | ||
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| Example: | ||
| <w> | ||
| $ xxd some.random.exe | head -n 1 | ||
| 00000000: 4d5a 9000 0345 0000 0400 0000 ffff 0000 MZ...E.......... | ||
| </w> | ||
| The entire binary will be reversed, and the first byte, will be the last byte. | ||
| <w> | ||
| 4d5a 9000 0345 .... <-- <r>reversed</r> --> .... 4503 0090 5a4d | ||
| </w> | ||
| Disassembly (x86): | ||
| <w> | ||
| 45 inc ebp | ||
| 03 00 add eax,DWORD PTR [eax] | ||
| 90 nop | ||
| 5a pop edx | ||
| 4d dec ebp | ||
| </w> | ||
| Scores will be calculated based on both the size of the executable, as well as | ||
| the percentage of bytes executed when it is run. | ||
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| An easy solution would be to just have the binary end, and append the binary | ||
| backwards at the end of the original file. Because of this, in order to qualify | ||
| for entry, your binary must at a minimum execute > 50% of the bytes in your | ||
| binary, and must execute past the halfway mark in your binary as well. | ||
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| <k>───<w> File Formats </w>───────────────────────────────────────────────────────────<w>//</w>──</k> | ||
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| Any executable format will be accepted, and must run on an operating system or | ||
| piece of hardware that can be physically or virtually run. Feel free to think | ||
| far beyond the typical PE/ELF/Mach-o binary types, and work with something you | ||
| feel you can express yourself best with. This includes ROMs, bootloaders, | ||
| firmware or anything else that can execute on a processor. | ||
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| For a list of binary formats, check <a href="https://en.wikipedia.org/wiki/Comparison_of_executable_file_formats">here</a>! | ||
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| You must have a working copy that runs on your target system, and instructions | ||
| for running the binary must be provided with your submission! | ||
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| <k>───<w> tl;dr </w>──────────────────────────────────────────────────────────────────<w>//</w>──</k> | ||
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| Rules: | ||
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| - Any executable binary format | ||
| - Any OS | ||
| - Any architecture | ||
| - Minimum should execute 50% of it's bytes | ||
| - Must execute within the mirrored section | ||
| - Must read the same forwards as it does backwards | ||
| - Must actually run on the target system | ||
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| Submissions: | ||
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| - Submit the binary, source and instructions to run (preferably in a Git repo) | ||
| - Include a SHA256 hash of your file both forwards and backwards (should match) | ||
| - Extra credit: Include a write up/blog link describing your process | ||
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| Scoring: | ||
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| - Size | ||
| - Percentage of bytes executed | ||
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| The challenge will run until Friday, August 28th 2020 @ 8:00 PM America/New_York | ||
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| Tweet or DM your submissions to <a href="https://twitter.com/netspooky">@netspooky</a> on Twitter, or alternatively email | ||
| info [at] thugcrowd [dot] com | ||
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| We will do publish a blog and possibly do a live stream to review submissions | ||
| in the week following. We look forward to seeing what you come up with! | ||
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