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Every CTF
2023from public repositories

Ctf Easter Writeups 2023

61 challenges with 68 published solutions between them. The writeups for this event were found in public repositories. Each link is pinned to the commit it was read from.

Where these writeups live

Uncategorised29

The upstream scoreboard did not say, so neither do we.

Solve it with:Cipher identifier and automatic decoderLearn: Recognising encodings

Misc13

Everything that fits no other box: esolangs, puzzles, scripting exercises, and the jail escapes that have not yet earned their own category.

Solve it with:Brainfuck and esolang decoderCipher identifier and automatic decoderRegex tester with match offsets and capture groupsLearn: Recognising encodings

OSINT6

Answer a question about the real world from public sources. The work is pivoting between identifiers, not exploiting anything.

Solve it with:EXIF metadata viewerQR code decoder

Steganography5

Find the payload hidden inside a carrier that looks ordinary. Bit planes, appended data, metadata, and audio spectrograms.

Solve it with:LSB steganography extractorPNG chunk analyzerAudio spectrogram and SSTV decoderZero-width character and text steganography decoderLearn: Steganography

Web4

Reach data or functionality the application meant to keep from you - through its inputs, its tokens, or its trust in the client.

Solve it with:JWT decoder and signature verifierJWT alg=none bypass generatorWeb attack payload catalogJWT secret brute forceLearn: Sessions, tokens and access control

Reverse engineering4

Work out what a compiled program does without its source, then work backwards from the check to the input that passes it.

Solve it with:Strings extractor for binaries and blobsWebAssembly disassemblerJava .class disassemblerPython .pyc bytecode disassemblerLearn: Binary exploitation

Other 2023 events