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Every CTF
2016from the authors’ own sites

TWCTF 2016

7 challenges with 15 published solutions between them. The writeups for this event were found on the authors’ own sites.

Where these writeups live

Misc2

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

Web2

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 engineering1

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

Binary exploitation1

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

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

Other 2016 events