Generates shellcode from a masm compiled file. Instructions in file comments!.

gen_shellcode_masm.py

# Create a shellcode.ASM file
# the shellcode shall reside in the text segment
# compile it using ml64 /c shellcode.ASM
# run this file

f = open("shellcode.obj", "rb")
stream = f.read()
SizeOfFileHeader = 0x14

SizeOfBuffer = int.from_bytes(stream[SizeOfFileHeader+0x10:SizeOfFileHeader+0x14], "little") #SizeOfRaw Text segment
PtrToRaw     = int.from_bytes(stream[SizeOfFileHeader+0x14:SizeOfFileHeader+0x18], "little") #File offset of text segment
TextBuffer   = stream[PtrToRaw:PtrToRaw+SizeOfBuffer]

print("Writing:",TextBuffer)

f.close()

f1 = open("shellcode.bin", "wb")
f1.write(TextBuffer)
f1.close()