01 - Parse and manipulate formats

The objective of this tutorial is to give an overview of the LIEF’s API to parse and manipulate formats

By Romain Thomas - @rh0main


We start by the ELF format. To create an ELF.Binary from a file we just have to give its path to the lief.parse() or lief.ELF.parse() functions


With the Python API, these functions have the same behaviour but in C++, LIEF::Parser::parse() will return a pointer to a LIEF::Binary object whereas LIEF::ELF::Parser::parse() will return a LIEF::ELF::Binary object

import lief
binary = lief.parse("/bin/ls")

Once the ELF file has been parsed, we can access to its Header:

header = binary.header

Change the entry point and the target architecture (ARCH)

header.entrypoint = 0x123
header.machine_type = lief.ELF.ARCH.AARCH64

and then rebuild it:


We can also iterate over binary Sections as follows:

for section in binary.sections:
  print(section.name) # section's name
  print(section.size) # section's size
  print(len(section.content)) # Should match the previous print

To modify the content of the .text section:

text = binary.get_section(".text")
text.content = bytes([0x33] * text.size)


As for the ELF part, we can use the lief.parse() or lief.PE.parse() functions to create a PE.Binary

import lief
binary = lief.parse("C:\\Windows\\explorer.exe")

To access to the different PE headers (DosHeader, Header and OptionalHeader):


One can also access to the imported functions using two methods. The abstract one which will the use the LIEF abstract layer:

for func in binary.imported_functions:

To have a better granularity on the location of the imported function in libraries or to access to other fields of the PE imports:

for imported_library in binary.imports:
  print("Library name: " + imported_library.name)
  for func in imported_library.entries:
    if not func.is_ordinal:

LIEF enables to modify all the properties of the Import and ImportEntry but to take account of the modification, the Builder must be configured as follow:

builder = lief.PE.Builder(binary)