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Every CTF
2023weight 23.84ckc9759

GREP CTF

17 challenges with 18 published community solutions between them. Solution links go to CTFtime’s task page, which aggregates every writeup for a challenge - individual blog posts rot, the aggregator does not.

Full task list on CTFtime

Uncategorised9

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

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

Misc4

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

OSINT2

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

Forensics1

Recover something from a file, a capture, or a disk image - often from a part of it the format says is unused.

Solve it with:File type identifier by magic bytesMagic byte and file signature tablePCAP analyzer for CTF network forensicsEXIF metadata viewerLearn: File forensics and carvingLearn: Network forensics

Cryptography1

Recover a plaintext or a key from something that was supposed to protect it. In practice: identify the scheme, find the parameter the author got wrong, exploit it.

Solve it with:Cipher identifier and automatic decoderVigenere cipher solver with automatic key recoveryRSA decryption and attack runnerWiener’s attack on small RSA private exponentsIn-browser hash cracker with rule transformsLearn: Classical ciphers and frequency analysisLearn: RSA and the parameters that break it

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