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Every CTF
2025picoctfsolutions.compicoCTF

picoCTF 2025

41 challenges with 41 published solutions between them. Solution links go to picoctfsolutions.com, which is the only writeup source this index uses for picoCTF - one worked solution per challenge, rather than an aggregate of other people’s posts.

Every writeup on picoctfsolutions.com

Web11

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: Web attacks and session tokens

  • 3v@l

    1 writeup
    • command-injection

  • Apriti sesamo

    1 writeup
    • authentication-bypass
    • command-injection

  • Cookie Monster Secret Recipe

    1 writeup
    • cookie-manipulation
    • session-hijacking

  • head-dump

    1 writeup
    • endpoint-enumeration
    • http-headers

  • n0s4n1ty 1

    1 writeup
    • file-upload
    • command-injection

  • Pachinko

    1 writeup
    • javascript-deobfuscation
    • source-inspection

  • Pachinko Revisited

    1 writeup
    • javascript-deobfuscation
    • source-inspection

  • secure-email-service

    1 writeup
    • source-inspection
    • authentication-bypass

  • SSTI1

    1 writeup
    • ssti

  • SSTI2

    1 writeup
    • ssti
    • filter-bypass

  • WebSockFish

    1 writeup
    • websocket
    • source-inspection

Reverse engineering7

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

Cryptography6

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

  • ChaCha Slide

    1 writeup
    • stream-cipher

  • EVEN RSA CAN BE BROKEN???

    1 writeup
    • rsa
    • factoring

  • Guess My Cheese (Part 1)

    1 writeup
    • custom-cipher
    • classical-cipher

  • Guess My Cheese (Part 2)

    1 writeup
    • custom-cipher
    • classical-cipher

  • hashcrack

    1 writeup
    • hash-cracking
    • wordlist-generation

  • Ricochet

    1 writeup
    • custom-cipher

Binary exploitation6

Turn a memory-safety bug in a native binary into control of execution. Usually a stack overflow, a format string, or a heap primitive.

Solve it with:ROP gadget finderShellcode assembler and libraryCyclic pattern generator and offset finderFormat string exploit builderLearn: Binary exploitation

Forensics6

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

  • Bitlocker-1

    1 writeup
    • disk-forensics
    • bitlocker

  • Bitlocker-2

    1 writeup
    • disk-forensics
    • bitlocker

  • Event-Viewing

    1 writeup
    • windows-event-logs
    • log-analysis

  • flags are stepic

    1 writeup
    • steganography
    • lsb-stego

  • Ph4nt0m 1ntrud3r

    1 writeup
    • steganography
    • image-analysis

  • RED

    1 writeup
    • steganography
    • lsb-stego

Misc5

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

Other 2025 events