2014-10-10 22:27:27 -04:00

83 lines
2.8 KiB
Python
Executable File

#!/usr/bin/python
import utils
import sys
import ctypes
import codecs
if sys.platform.startswith('linux'):
from ctypes import *
# Initialise ctypes prototype for mprotect().
# According to the manpage:
# int mprotect(const void *addr, size_t len, int prot);
libc = CDLL("libc.so.6")
mprotect = libc.mprotect
mprotect.restype = c_int
mprotect.argtypes = [c_void_p, c_size_t, c_int]
# PROT_xxxx constants
# Output of gcc -E -dM -x c /usr/include/sys/mman.h | grep PROT_
# #define PROT_NONE 0x0
# #define PROT_READ 0x1
# #define PROT_WRITE 0x2
# #define PROT_EXEC 0x4
# #define PROT_GROWSDOWN 0x01000000
# #define PROT_GROWSUP 0x02000000
PROT_NONE = 0x0
PROT_READ = 0x1
PROT_WRITE = 0x2
PROT_EXEC = 0x4
# Machine code of an empty C function, generated with gcc
# Disassembly:
# 55 push %ebp
# 89 e5 mov %esp,%ebp
# 5d pop %ebp
# c3 ret
#code = "\x48\x31\xc0\x50\x48\xbf\x2f\x62\x69\x6e\x2f\x2f\x73\x68\x57\xb0\x3b\x48\x89\xe7\x48\x31\xf6\x48\x31\xd2\x0f\x05"
code = codecs.escape_decode(sys.argv[1])[0]
# Get the address of the code
addr = addressof(cast(c_char_p(code), POINTER(c_char)).contents)
# Get the start of the page containing the code and set the permissions
pagesize = 0x1000
pagestart = addr & ~(pagesize - 1)
if mprotect(pagestart, pagesize, PROT_READ|PROT_WRITE|PROT_EXEC):
raise RuntimeError("Failed to set permissions using mprotect()")
# Generate ctypes function object from code
functype = CFUNCTYPE(None)
f = functype(addr)
# Call the function
print("Calling f()")
f()
elif sys.platform.startswith('win'):
buf = codecs.escape_decode(sys.argv[1])[0]
shellcode = bytearray(buf)
ptr = ctypes.windll.kernel32.VirtualAlloc(ctypes.c_int(0),
ctypes.c_int(len(shellcode)),
ctypes.c_int(0x3000),
ctypes.c_int(0x40))
buf = (ctypes.c_char * len(shellcode)).from_buffer(shellcode)
ctypes.windll.kernel32.RtlMoveMemory(ctypes.c_int(ptr),
buf,
ctypes.c_int(len(shellcode)))
ht = ctypes.windll.kernel32.CreateThread(ctypes.c_int(0),
ctypes.c_int(0),
ctypes.c_int(ptr),
ctypes.c_int(0),
ctypes.c_int(0),
ctypes.pointer(ctypes.c_int(0)))
ctypes.windll.kernel32.WaitForSingleObject(ctypes.c_int(ht),ctypes.c_int(-1))