Skip to main content
This example demonstrates how to use Architecture Hooks to modify the behavior of existing architectures, such as changing instruction mnemonics or customizing disassembly.

​
Overview

The arch_hook.py example shows how to:
  • Create an architecture hook to modify existing architecture behavior
  • Override specific methods like get_instruction_text
  • Change instruction mnemonics in the disassembly view
  • Register custom architecture behavior

​
Complete Source Code

from binaryninja.architecture import Architecture, ArchitectureHook


class X86ReturnHook(ArchitectureHook):
    def get_instruction_text(self, data, addr):
        # Call the original implementation's method by calling the superclass
        result, length = super(X86ReturnHook, self).get_instruction_text(data, addr)

        # Patch the name of the 'retn' instruction to 'ret'
        if len(result) > 0 and result[0].text == 'retn':
            result[0].text = 'ret'

        return result, length


# Install the hook by constructing it with the desired architecture to hook, then registering it
X86ReturnHook(Architecture['x86']).register()

​
Key Concepts Explained

1
Create an Architecture Hook Class
2
class X86ReturnHook(ArchitectureHook):
3
Extend ArchitectureHook to create a hook for an existing architecture. The hook intercepts architecture methods and allows you to modify their behavior.
4
Override Architecture Methods
5
def get_instruction_text(self, data, addr):
    result, length = super(X86ReturnHook, self).get_instruction_text(data, addr)
6
Override methods from the base architecture:
7
  • get_instruction_text(data, addr) - Customize disassembly text
  • get_instruction_info(data, addr) - Modify instruction semantics
  • get_instruction_low_level_il(data, addr, il) - Customize IL lifting
    • 8
    Always call the superclass method first to get the original behavior, then modify as needed.
    9
    Modify Instruction Tokens
    10
    if len(result) > 0 and result[0].text == 'retn':
    result[0].text = 'ret'
    11
    The result is a list of InstructionTextToken objects that represent the disassembly:
    12
  • Each token has a text property (the string to display)
  • Tokens also have a type property (e.g., instruction mnemonic, register, operand)
  • Modify the text or add/remove tokens as needed
    • 13
    Register the Hook
    14
    X86ReturnHook(Architecture['x86']).register()
    15
    Instantiate the hook with the target architecture and register it:
    16
  • Architecture['x86'] - References the built-in x86 architecture
  • .register() - Activates the hook for all future uses
  • Hooks apply globally once registered

    • ​
    Advanced Hook Examples

    ​
    Hook Multiple Methods

    from binaryninja.architecture import Architecture, ArchitectureHook
from binaryninja.enums import InstructionTextTokenType

class CustomARM64Hook(ArchitectureHook):
    def get_instruction_text(self, data, addr):
        result, length = super().get_instruction_text(data, addr)
        
        # Convert all register names to uppercase
        for token in result:
            if token.type == InstructionTextTokenType.RegisterToken:
                token.text = token.text.upper()
        
        return result, length
    
    def get_instruction_info(self, data, addr):
        info = super().get_instruction_info(data, addr)
        # Customize instruction info (branch targets, length, etc.)
        return info

CustomARM64Hook(Architecture['aarch64']).register()

    ​
    Add Custom Instruction Annotations

    from binaryninja.architecture import Architecture, ArchitectureHook
from binaryninja.enums import InstructionTextTokenType
from binaryninja.function import InstructionTextToken

class AnnotationHook(ArchitectureHook):
    def get_instruction_text(self, data, addr):
        result, length = super().get_instruction_text(data, addr)
        
        # Add custom annotation for syscall instructions
        if len(result) > 0 and result[0].text == 'syscall':
            result.append(InstructionTextToken(
                InstructionTextTokenType.TextToken,
                "  ; System call"
            ))
        
        return result, length

AnnotationHook(Architecture['x86_64']).register()

    ​
    Normalize Instruction Mnemonics

    class MnemonicNormalizer(ArchitectureHook):
    # Map of mnemonics to normalize
    MNEMONIC_MAP = {
        'retn': 'ret',
        'retf': 'ret',
        'jmp': 'jump',
        'je': 'jump_equal',
    }
    
    def get_instruction_text(self, data, addr):
        result, length = super().get_instruction_text(data, addr)
        
        if len(result) > 0:
            mnemonic = result[0].text
            if mnemonic in self.MNEMONIC_MAP:
                result[0].text = self.MNEMONIC_MAP[mnemonic]
        
        return result, length

MnemonicNormalizer(Architecture['x86']).register()

    ​
    Loading the Hook

    ​
    As a Plugin

    Save the script to your Binary Ninja plugins directory: 
    ~/.binaryninja/plugins/arch_hook.py  # Linux/Mac
%APPDATA%\Binary Ninja\plugins\arch_hook.py  # Windows
    The hook will be applied automatically when Binary Ninja starts.

    ​
    In a Script

    import binaryninja
from arch_hook import X86ReturnHook

# Hook is registered when module is imported
bv = binaryninja.load("/path/to/binary")
# Disassembly will now show 'ret' instead of 'retn'

    ​
    Expected Behavior

    ​
    Before Hook

    0x401000  push    ebp
0x401001  mov     ebp, esp
0x401003  xor     eax, eax
0x401005  retn          ; Original mnemonic

    ​
    After Hook

    0x401000  push    ebp
0x401001  mov     ebp, esp
0x401003  xor     eax, eax
0x401005  ret           ; Modified mnemonic

    ​
    Available Hook Methods

    You can override these methods in your ArchitectureHook subclass:

    ​
    Disassembly Methods

    • get_instruction_text(data, addr) - Customize instruction text tokens
    • get_instruction_info(data, addr) - Modify instruction metadata
    • get_instruction_length(data, addr) - Override instruction length

    ​
    IL Lifting Methods

    • get_instruction_low_level_il(data, addr, il) - Customize LLIL translation

    ​
    Register and Flag Methods

    • get_register_name(reg) - Customize register names
    • get_flag_name(flag) - Customize flag names

    ​
    Other Methods

    • assemble(code, addr) - Customize assembler behavior

    ​
    Use Cases

    • Mnemonic Standardization - Normalize instruction names across architectures
    • Custom Annotations - Add domain-specific comments to disassembly
    • Obfuscation Handling - Simplify obfuscated instruction patterns
    • Compatibility Layers - Adapt architecture variants (e.g., ARM vs Thumb)
    • Education - Simplify instruction names for learning purposes

    ​
    Important Notes

    • Architecture hooks are global - they affect all binaries using that architecture
    • Modifying IL lifting can break analysis if done incorrectly
    • Test hooks thoroughly before deploying
    • Use hooks for display modifications, not for changing instruction semantics

    Build docs developers (and LLMs) love

    Get started for freeTalk to us