radare2

Complete, multi-architecture framework for binary reverse engineering: a modular command-line toolset for forensics, exploitation, and debugging.

Radare2 (r2) is your go-to low-level toolchain for deep binary analysis. It provides a full-featured environment built around a powerful command-line interface (CLI), though GUIs like Iaito exist. The framework supports a wide array of architectures (x86, ARM, MIPS, etc.) and file formats (ELF, PE, Mach-O), making it highly versatile. Core capabilities include advanced code analysis, disassembly, integrated debugging (local and remote via GDB), hex editing, and binary patching. Its modular design and extensive scripting support (Python, JavaScript, etc.) allow for complex automation and custom tooling, making it a favorite for security researchers and CTF teams globally.

https://www.radare.org/