mem_edit

mem_edit is a multi-platform memory editing library written in Python.

Homepage: https://mpxd.net/code/jan/mem_edit

Capabilities:

• Scan all readable memory used by a process.
  • Optionally restrict searches to regions with read + write permissions.
  • Report on address space allocation
• Read/write using ctypes objects
  • Basic types, e.g. ctypes.c_ulong()
  • Arrays, e.g. (ctypes.c_byte * 4)()
  • Instances of ctypes.Structure or ctypes.Union and subclasses.
• Run on Windows and Linux

Installation

Dependencies:

• python 3 (written and tested with 3.7)
• ctypes
• typing (for type annotations)

Install with pip, from PyPI (preferred):

pip3 install mem_edit

Install with pip from git repository

pip3 install git+https://mpxd.net/code/jan/mem_edit.git@release

Documentation

Most functions and classes are documented inline. To read the inline help,

import mem_edit
help(mem_edit.Process)

Examples

Increment a magic number (unsigned long 1234567890) found in 'magic.exe':

    import ctypes
    from mem_edit import Process

    magic_number = ctypes.ulong(1234567890)

    pid = Process.get_pid_by_name('magic.exe')
    with Process.open_process(pid) as p:
        addrs = p.search_all_memory(magic_number)

        # We don't want to edit if there's more than one result...
        assert(len(addrs) == 1)

        # We don't actually have to read the value here, but let's do so anyways...
        num_ulong = p.read_memory(addrs[0], ctypes.c_ulong())
        num = num_ulong.value

        p.write_memory(addrs[0], ctypes.c_ulong(num + 1))

Narrow down a search after a value changes:

    import ctypes
    from mem_edit import Process

    initial_value = 40
    final_value = 55

    pid = Process.get_pid_by_name('monitor_me.exe')
    with Process.open_process(pid) as p:
        addrs = p.search_all_memory(ctypes.c_int(initial_value))

        input('Press enter when value has changed to ' + str(final_value))

        filtered_addrs = p.search_addresses(addrs, ctypes.c_int(final_value))

        print('Found addresses:')
        for addr in filtered_addrs:
            print(hex(addr))

Read and alter a structure:

    import ctypes
    from mem_edit import Process

    class MyStruct(ctypes.Structure):
        _fields_ = [
               ('first_member', ctypes.c_ulong),
               ('second_member', ctypes.c_void_p),
               ]

    pid = Process.get_pid_by_name('something.exe')

    with Process.open_process(pid) as p:
        s = MyStruct()
        s.first_member = 1234567890
        s.second_member = 0x1234

        addrs = p.search_all_memory(s)
        print(addrs)

        p.write_memory(0xafbfe0, s)