reverse-engineering

Files (26)

• SKILL.md
• INDEX.md · reference/
• custom-vm-bytecode.md · reference/
• reverse-engineering-principles.md · reference/
• int3-detection-bypass.md · reference/scenarios/anti-debug/
• isdebuggerpresent-bypass.md · reference/scenarios/anti-debug/
• ptrace-bypass.md · reference/scenarios/anti-debug/
• timing-checks-bypass.md · reference/scenarios/anti-debug/
• bytecode-disassembly.md · reference/scenarios/custom-vm/
• frida-hooking.md · reference/scenarios/dynamic-analysis/
• gdb-scripting.md · reference/scenarios/dynamic-analysis/
• ltrace-strace.md · reference/scenarios/dynamic-analysis/
• esp32-xtensa-flash-dump.md · reference/scenarios/firmware/
• kernel-rootkit-module.md · reference/scenarios/kernel/
• callfuscation.md · reference/scenarios/obfuscation/
• d-fiber-callfuscation.md · reference/scenarios/obfuscation/
• hash-dispatcher-chain.md · reference/scenarios/obfuscation/
• mba-deobfuscation.md · reference/scenarios/obfuscation/
• packed-binaries.md · reference/scenarios/obfuscation/
• python-bytecode-payload.md · reference/scenarios/obfuscation/
• string-obfuscation.md · reference/scenarios/obfuscation/
• disassembly-recipe.md · reference/scenarios/static-analysis/
• elf-analysis.md · reference/scenarios/static-analysis/
• pe-analysis.md · reference/scenarios/static-analysis/
• string-extraction.md · reference/scenarios/static-analysis/
• unity-il2cpp-recipe.md · reference/scenarios/static-analysis/

SKILL.md (first lines)

# Reverse Engineering

## Scope

Reverse engineering compiled binaries (ELF, PE, Mach-O) and bytecode artifacts to recover algorithms, validate inputs, or build static solvers. Focused on the recurring CTF / malware-analysis pattern of a host binary that loads a "program" file under a custom ISA — recognising the dispatcher loop, mapping opcodes to Python lambdas, and inverting the transformation chain in pure Python without executing the host. Also covers callfuscation (control-flow chunking), MBA (mixed boolean-arithmetic) operator obfuscation, encrypted-handler tricks, and three-layer deobfuscation pipelines.

## When to use

- A binary plus a "program data" file are delivered together and the binary appears to be an interpreter (themed opcode names, dispatcher switch / jump table).
- Disassembly reveals a `while(true){ op = mem[pc++]; switch(op){...}; }` style loop or jump-table indexed by opcode.
- The binary is heavily obfuscated (callfuscation, MBA wrappers, encrypted handlers in `.data` decrypted to RWX at startup).
- You need to recover an algorithm or check function from native code without dynamic execution (anti-debug, wrong arch, no TTY).
- Static-first reverse engineering is preferred (faster, more reliable than emulator chains).

## References

- [reference/custom-vm-bytecode.md](reference/custom-vm-bytecode.md) — recognising and inverting custom stack/register/tape VMs; callfuscation linearization; MBA operator identification; encrypted-handler decryption.

From transilienceai/communitytools, MIT.

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