CTF Reverse Engineering

Quick reference for RE challenges. For detailed techniques, see supporting files.

Additional Resources

tools.md - Tool-specific commands (GDB, Ghidra, radare2, IDA, Binary Ninja, dogbolt.org, RISC-V with Capstone)
patterns.md - Foundational binary patterns: custom VMs, anti-debugging, nanomites, self-modifying code, XOR ciphers, mixed-mode stagers, LLVM obfuscation, S-box/keystream, SECCOMP/BPF, exception handlers, memory dumps, byte-wise transforms, x86-64 gotchas, signal-based exploration, malware anti-analysis, multi-stage shellcode, timing side-channel
patterns-ctf.md - Competition-specific patterns: hidden emulator opcodes, LD_PRELOAD key extraction, SPN static extraction, image XOR smoothness, byte-at-a-time cipher, mathematical convergence bitmap, Windows PE XOR bitmap OCR, two-stage RC4+VM loaders, GBA ROM meet-in-the-middle, Sprague-Grundy game theory, kernel module maze solving, multi-threaded VM channels, multi-layer self-decrypting brute-force, embedded ZIP+XOR license, stack string deobfuscation, prefix hash brute-force, CVP/LLL lattice for integer validation, decision tree function obfuscation, GLSL shader VM, GF(2^8) Gaussian elimination, Z3 single-line Python circuit, sliding window popcount
languages.md - Language/platform-specific: Python bytecode & opcode remapping, Python version-specific bytecode, DOS stubs, Unity IL2CPP, Brainfuck/esolangs, UEFI, transpilation to C, code coverage side-channel, OPAL functional reversing, non-bijective substitution, Android JNI RegisterNatives, Ruby/Perl polyglot