265 lines
9.5 KiB
Python
265 lines
9.5 KiB
Python
import json
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import lief
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lief.disable_leak_warning() # warnings to disable for the callback
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with open("lib/WindowsDllsExport/win10-19043-exports.json", "rb") as f:
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api_info = json.load(f)
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dump_path = "rsc/wave-0001.dump"
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# dump_path = "rsc/wave-0002.dump"
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iat_json_path = "rsc/upx-hostname.exe.bin_iat_wave1.json"
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# iat_json_path = "rsc/000155f2e0360f6ff6cd.exe_iat_wave2.json"
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def hex_address_to_memory_representation(hex_addr: str, is_32b: bool, is_little_endian: bool) -> list[int]:
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adress_size = 4 if is_32b else 8
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mem_value = [0x00] * adress_size
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hex_addr = hex_addr[::-1][:-2] # reversing order and stripping zero
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for i in range(0, adress_size):
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byte_str = hex_addr[i * 2 : (i + 1) * 2][::-1]
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mem_value[i] += int(byte_str, 16)
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if not is_little_endian:
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mem_value = mem_value[::-1] # reverse byte order for big endian
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return mem_value
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# Retrives all unique DLL names being imported
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def get_used_dlls(calls: list[dict[str, str]]) -> set[str]:
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res = set()
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for call in calls:
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res.add(call["name"].split("!")[0])
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return res
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# Retrieves all unique function names used for a single DLL name
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def get_used_functions_from_dll(dllname, calls):
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res = set()
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for [dll, func] in map(lambda x: x["name"].split("!"), calls):
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if dll == dllname:
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res.add(func)
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return res
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def patch_direct_adress_call(pe: lief.PE.Binary, rva: int, instruction_offset: int):
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# We can manually patch the instruction here: FF 15 08 10 00 01 represents `call [0x01001080]`
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new_value = hex_address_to_memory_representation(
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hex(rva + pe.imagebase),
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pe.abstract.header.is_32,
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pe.abstract.header.endianness == lief.Header.ENDIANNESS.LITTLE,
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)
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pe.patch_address(instruction_offset, [0xFF, 0x15] + new_value, lief.Binary.VA_TYPES.RVA)
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def patch_direct_adress_jump(pe: lief.PE.Binary, rva: int, instruction_offset: int):
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# We can manually patch the instruction here: FF 15 08 10 00 01 represents `call [0x01001080]`
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new_value = hex_address_to_memory_representation(
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hex(rva + pe.imagebase),
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pe.abstract.header.is_32,
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pe.abstract.header.endianness == lief.Header.ENDIANNESS.LITTLE,
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)
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pe.patch_address(instruction_offset, [0xFF, 0x25] + new_value, lief.Binary.VA_TYPES.RVA)
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def patch_instr_to_new_IAT_entry(pe: lief.PE.Binary, call: dict[str, str], rva: int):
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base = pe.imagebase
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instruction_offset = int(call["adress"], 16) - base
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memview = pe.get_content_from_virtual_address(instruction_offset, 2)
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if [memview[0], memview[1]] == [0xFF, 0x15]:
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patch_direct_adress_call(pe, rva, instruction_offset)
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elif [memview[0], memview[1]] == [0xFF, 0x25]:
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patch_direct_adress_jump(pe, rva, instruction_offset)
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def patch_addr_found_in_mem(pe: lief.PE.Binary, rva: int, old_addr: str):
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is_32 = pe.abstract.header.is_32
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little_endian = pe.abstract.header.endianness == lief.Header.ENDIANNESS.LITTLE
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# scan memory for reference to old addr
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old_addr_mem_repr = hex_address_to_memory_representation(
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old_addr,
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is_32,
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pe.abstract.header.endianness == lief.Header.ENDIANNESS.LITTLE,
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)
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new_addr = hex_address_to_memory_representation(
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hex(rva + pe.imagebase),
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is_32,
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little_endian,
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)
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adresses_to_patch = []
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for section in pe.sections:
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for i in range(len(section.content)):
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found = True
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for j in range(len(old_addr_mem_repr)):
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if i + j >= len(section.content) or section.content[i + j] != old_addr_mem_repr[j]:
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found = False
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break
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if found:
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old_addr_ref = hex_address_to_memory_representation(
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hex(
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section.virtual_address + i + pe.imagebase,
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),
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is_32,
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little_endian,
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)
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for section in pe.sections:
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for k in range(len(section.content)):
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foundxref = True
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for L in range(len(old_addr_ref)):
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if k + L < len(section.content) and section.content[k + L] != old_addr_ref[L]:
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foundxref = False
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break
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if foundxref:
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adresses_to_patch.append(section.virtual_address + k)
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for addr in adresses_to_patch:
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print(f"patched {hex(addr)}")
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pe.patch_address(addr, new_addr, lief.Binary.VA_TYPES.RVA)
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def patch_to_new_IAT(pe: lief.PE.Binary, imp: lief.PE.Import, entry: lief.PE.ImportEntry, rva: int):
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# print(f"{imp.name}!{entry.name}: 0x{rva:010x}")
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for call in filter(lambda x: x["name"] == f"{imp.name.upper()}!{entry.name}", calls):
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patch_instr_to_new_IAT_entry(pe, call, rva)
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# patch additional non-call related info
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print(entry.name)
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for func in filter(lambda x: x["name"] == entry.name and x["dll"] == imp.name, procaddr_list):
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# print(func["name"])
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patch_addr_found_in_mem(pe, rva, func["addr"])
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def get_list_of_procaddr_functions(prevwave_info):
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res = []
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for call in prevwave_info:
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# first only including imported dlls
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res_new = {}
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for export in api_info:
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if export["dllname"] in dll_calls_list and export["exportname"] == call["function"]:
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res_new = {
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"name": export["exportname"],
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"dll": export["dllname"],
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"addr": call["func_addr"],
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}
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break
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if res_new == {}:
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# try adding a new dll
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for export in api_info:
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if export["exportname"] == call["function"]:
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res_new = {
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"name": export["exportname"],
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"dll": export["dllname"],
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"addr": call["func_addr"],
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}
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break
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if res_new != {}:
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res.append(res_new)
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return res
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# wave dump file to patch
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with open(dump_path, "rb") as f:
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pe = lief.parse(f)
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assert isinstance(pe, lief.PE.Binary)
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# JSON generated with the python reader files
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with open(iat_json_path, "r") as iat_json_input:
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iat_data = json.load(iat_json_input)
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calls: list[dict[str, str]] = iat_data["calls"]
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wave_entry = int(iat_data["entry"], 16)
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# create new section
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patch_section = lief.PE.Section(".iatpatch")
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content = []
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# initiate registry values
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reg_to_inst_code = {
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"EAX": 0xC0,
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"EBX": 0xC3,
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"ECX": 0xC1,
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"EDX": 0xC2,
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"ESI": 0xC6,
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"EDI": 0xC7,
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"EBP": 0xC5,
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# "ESP": 0xC4,
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}
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for reg in iat_data["entry_reg_values"].keys():
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if reg not in reg_to_inst_code:
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continue
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new_instruction = [
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0xC7,
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reg_to_inst_code[reg],
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] + hex_address_to_memory_representation(
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iat_data["entry_reg_values"][reg].strip(),
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pe.abstract.header.is_32,
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pe.abstract.header.endianness == lief.Header.ENDIANNESS.LITTLE,
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)
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for byte in new_instruction:
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content.append(byte)
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# add ret to actual OEP
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content += [0x68] + hex_address_to_memory_representation(
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hex(wave_entry),
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pe.abstract.header.is_32,
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pe.abstract.header.endianness == lief.Header.ENDIANNESS.LITTLE,
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)
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content += [0xC3]
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patch_section.content = content
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# add new section to PE
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pe.add_section(patch_section)
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# patch entrypoint
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# entrypoint_format = int(hex(pe.get_section(".iatpatch").virtual_address)[-4:], 16)
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entrypoint_format = int(hex(pe.get_section(".iatpatch").virtual_address)[-4:], 16)
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pe.optional_header.addressof_entrypoint = entrypoint_format
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# remove all current imports
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pe.remove_all_imports()
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# recreate all DLL imports from calls detected
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dll_calls_list = []
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imported_dll_list = []
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func_calls_list = []
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for dll in get_used_dlls(calls):
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dll_calls_list.append(dll.lower())
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imported_dll = pe.add_import(dll.lower())
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imported_dll_list.append(imported_dll)
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# recreate all function calls related to that dll import
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for func in get_used_functions_from_dll(dll, calls):
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func_calls_list.append(func)
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imported_dll.add_entry(func)
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# get list of functions called with getprocaddr
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procaddr_list = get_list_of_procaddr_functions(iat_data["prevwave_getprocaddr"])
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for func in procaddr_list:
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if func["name"] in func_calls_list: # call already added
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continue
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if func["dll"] in dll_calls_list: # dll already added
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imported_dll_list[dll_calls_list.index(func["dll"])].add_entry(func["name"])
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else: # we need to import the new DLL
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dll_calls_list.append(func["dll"])
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imported_dll = pe.add_import(func["dll"])
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imported_dll_list.append(imported_dll)
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func_calls_list.append(func["name"])
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imported_dll.add_entry(func["name"])
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# At this point, the new IAT will only be constructed when the PE is written. We therefore need to make a callback function to patch calls afterwards.
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# Define all sections as writeable, to help with some weird stuff we're seeing
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for section in pe.sections:
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section.characteristics = (
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lief.PE.Section.CHARACTERISTICS.MEM_WRITE.value
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+ lief.PE.Section.CHARACTERISTICS.MEM_READ.value
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+ lief.PE.Section.CHARACTERISTICS.MEM_EXECUTE.value
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+ lief.PE.Section.CHARACTERISTICS.CNT_INITIALIZED_DATA.value
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)
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# write result
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config = lief.PE.Builder.config_t()
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config.imports = True # allows the config of the writer to write a new IAT
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config.resolved_iat_cbk = patch_to_new_IAT # callback after the IAT has been written
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pe.write("patched.exe", config)
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print("Wrote the patched executable as patched.exe")
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