Files
SuperMega/pe/superpe.py
T
2024-04-12 22:01:10 +01:00

293 lines
11 KiB
Python

import pefile
import capstone
from enum import IntEnum
import logging
from typing import List
from utils import hexdump
from model.defs import *
logger = logging.getLogger("superpe")
class PeSection():
def __init__(self, pefile_section: pefile.SectionStructure):
self.name: str = pefile_section.Name.rstrip(b'\x00').decode("utf-8")
self.raw_addr: int = pefile_section.PointerToRawData
self.raw_size: int = pefile_section.SizeOfRawData
self.virt_addr: int = pefile_section.VirtualAddress
self.virt_size: int = pefile_section.Misc_VirtualSize
self.pefile_section: pefile.SectionStructure = pefile_section
class SuperPe():
IMAGE_DIRECTORY_ENTRY_SECURITY = 4
IMAGE_DIRECTORY_ENTRY_BASERELOC = 5
IMAGE_DIRECTORY_ENTRY_TLS = 9
IMAGE_REL_BASED_ABSOLUTE = 0
IMAGE_REL_BASED_HIGH = 1
IMAGE_REL_BASED_LOW = 2
IMAGE_REL_BASED_HIGHLOW = 3
IMAGE_REL_BASED_HIGHADJ = 4
IMAGE_REL_BASED_DIR64 = 10
def __init__(self, infile: str):
self.filepath: str = infile
self.pe_sections: List[PeSection] = []
self.pe = pefile.PE(infile, fast_load=False)
for section in self.pe.sections:
self.pe_sections.append(PeSection(section))
self.pe.parse_data_directories()
self.ptrSize = 4
self.arch = self.getFileArch()
if self.arch == 'x64':
self.ptrSize = 8
def is_dll(self):
return self.filepath.endswith(".dll")
def is_64(self) -> bool:
return self.arch == 'x64'
def is_dotnet(self) -> bool:
# DotNet or not
# https://stackoverflow.com/questions/45574925/is-there-a-way-to-check-if-an-exe-is-dot-net-with-python-pefile
entry = self.pe.OPTIONAL_HEADER.DATA_DIRECTORY[14]
if entry.VirtualAddress != 0 and entry.Size != 0:
return True
return False
def get_physical_address(self, virtual_address):
# Iterate through the section headers to find which section contains the VA
for section in self.pe.sections:
# Check if the VA is within the range of this section
if section.VirtualAddress <= virtual_address < section.VirtualAddress + section.Misc_VirtualSize:
# Calculate the difference between the VA and the section's virtual address
virtual_offset = virtual_address - section.VirtualAddress
# Add the difference to the section's pointer to raw data
return virtual_offset
#physical_address = section.PointerToRawData + virtual_offset
#return physical_address
return None
def getFileArch(self):
if self.pe.FILE_HEADER.Machine == 0x014c:
return "x86"
if self.pe.FILE_HEADER.Machine == 0x8664:
return "x64"
raise Exception("Unsupported PE file architecture.")
def get_code_section(self):
entrypoint = self.pe.OPTIONAL_HEADER.AddressOfEntryPoint
for sect in self.pe.sections:
if sect.Characteristics & pefile.SECTION_CHARACTERISTICS['IMAGE_SCN_MEM_EXECUTE']:
if entrypoint >= sect.VirtualAddress and entrypoint <= sect.VirtualAddress + sect.Misc_VirtualSize:
return sect
return None
def get_code_section_data(self) -> bytes:
sect = self.get_code_section()
return bytes(sect.get_data())
def get_rwx_section(self):
# rwx section
entrypoint = self.pe.OPTIONAL_HEADER.AddressOfEntryPoint
for section in self.pe.sections:
if (section.Characteristics & pefile.SECTION_CHARACTERISTICS['IMAGE_SCN_MEM_READ'] and
section.Characteristics & pefile.SECTION_CHARACTERISTICS['IMAGE_SCN_MEM_WRITE'] and
section.Characteristics & pefile.SECTION_CHARACTERISTICS['IMAGE_SCN_MEM_EXECUTE']
):
if entrypoint > section.VirtualAddress and entrypoint < section.VirtualAddress + section.Misc_VirtualSize:
return section
return None
def get_section_by_name(self, name: str) -> PeSection:
for section in self.pe_sections:
if section.name == name:
return section
return None
def get_base_relocs(self):
base_relocs = []
if hasattr(self.pe, 'DIRECTORY_ENTRY_BASERELOC'):
for base_reloc in self.pe.DIRECTORY_ENTRY_BASERELOC:
for entry in base_reloc.entries:
rva = entry.rva
base_rva = entry.base_rva
reloc_type = pefile.RELOCATION_TYPE[entry.type][0]
base_relocs.append(PeRelocEntry(rva, base_rva, reloc_type))
return base_relocs
def get_iat_entries(self):
iat = {}
for entry in self.pe.DIRECTORY_ENTRY_IMPORT:
for imp in entry.imports:
dll_name = entry.dll.decode('utf-8')
if imp.name == None:
continue
imp_name = imp.name.decode('utf-8')
imp_addr = imp.address
if not dll_name in iat:
iat[dll_name] = []
iat[dll_name].append(IatEntry(dll_name, imp_name, imp_addr))
return iat
def write_code_section_data(self, data: bytes):
sect = self.get_code_section()
if len(data) != sect.SizeOfRawData:
logger.error(f'New code section data is larger than the original! {len(data)} != {sect.SizeOfRawData}')
return
self.pe.set_bytes_at_offset(sect.PointerToRawData, data)
def getSectionIndexByDataDir(self, dirIndex):
addr = self.pe.OPTIONAL_HEADER.DATA_DIRECTORY[dirIndex].VirtualAddress
i = 0
for sect in self.pe.sections:
if addr >= sect.VirtualAddress and addr < (sect.VirtualAddress + sect.Misc_VirtualSize):
return i
i += 1
logger.error(f'Could not find section with directory index {dirIndex}!')
return -1
def getRemainingRelocsDirectorySize(self):
relocsIndex = self.getSectionIndexByDataDir(SuperPe.IMAGE_DIRECTORY_ENTRY_BASERELOC)
out = self.pe.sections[relocsIndex].SizeOfRawData - self.pe.sections[relocsIndex].Misc_VirtualSize
return out
def getSectionIndexByName(self, name):
i = 0
for sect in self.pe.sections:
if sect.Name.decode().lower().startswith(name.lower()):
return i
i += 1
logger.error(f'Could not find section with name {name}!')
return -1
def addImageBaseRelocations(self, pageRva, relocs):
assert pageRva > 0
if not self.pe.has_relocs():
logger.error("No .reloc section")
raise(Exception("No .reloc section"))
imageBaseRelocType = SuperPe.IMAGE_REL_BASED_HIGHLOW
if self.arch == 'x64':
imageBaseRelocType = SuperPe.IMAGE_REL_BASED_DIR64
relocsSize = self.pe.OPTIONAL_HEADER.DATA_DIRECTORY[SuperPe.IMAGE_DIRECTORY_ENTRY_BASERELOC].Size
relocsIndex = self.getSectionIndexByDataDir(SuperPe.IMAGE_DIRECTORY_ENTRY_BASERELOC)
addr = self.pe.OPTIONAL_HEADER.DATA_DIRECTORY[SuperPe.IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress
sizeOfReloc = 2 * len(relocs) + 2 * 4
if sizeOfReloc >= self.getRemainingRelocsDirectorySize():
self.logger.warn('WARNING! Cannot add any more relocations to this file. Probably TLS Callback execution technique wont work.')
self.logger.warn(' Will try disabling relocations on output file. Expect corrupted executable though!')
self.pe.OPTIONAL_HEADER.DATA_DIRECTORY[SuperPe.IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress = 0
self.pe.OPTIONAL_HEADER.DATA_DIRECTORY[SuperPe.IMAGE_DIRECTORY_ENTRY_BASERELOC].Size = 0
return
relocDirRva = self.pe.sections[relocsIndex].VirtualAddress
self.pe.OPTIONAL_HEADER.DATA_DIRECTORY[SuperPe.IMAGE_DIRECTORY_ENTRY_BASERELOC].Size += sizeOfReloc
# VirtualAddress
self.pe.set_dword_at_rva(addr + relocsSize, pageRva)
# SizeOfBlock
self.pe.set_dword_at_rva(addr + relocsSize + 4, sizeOfReloc)
logger.info(f'Adding {len(relocs)} relocations for Page RVA 0x{pageRva:X} - size of block: 0x{sizeOfReloc:X}')
i = 0
for reloc in relocs:
reloc_offset = (reloc - pageRva)
reloc_type = imageBaseRelocType << 12
relocWord = (reloc_type | reloc_offset)
self.pe.set_word_at_rva(relocDirRva + relocsSize + 8 + i * 2, relocWord)
logger.info(f'\tReloc{i} for addr 0x{reloc:X}: 0x{relocWord:X} - 0x{reloc_offset:X} - type: {imageBaseRelocType}')
i += 1
## Helpers
def get_entrypoint(self) -> int:
return self.pe.OPTIONAL_HEADER.AddressOfEntryPoint
def set_entrypoint(self, entrypoint: int):
self.pe.OPTIONAL_HEADER.AddressOfEntryPoint = entrypoint
def write_pe_to_file(self, outfile: str):
self.pe.write(outfile)
def disasmBytes(self, cs, ks, disasmData, startOffset, length, callback = None, maxDepth = 5):
return self._disasmBytes(cs, ks, disasmData, startOffset, length, callback, maxDepth, 1)
def printInstr(self, instr, depth):
_bytes = [f'{x:02x}' for x in instr.bytes[:8]]
if len(instr.bytes) < 8:
_bytes.extend([' ',] * (8 - len(instr.bytes)))
instrBytes = ' '.join([f'{x}' for x in _bytes])
logger.debug('\t' * 1 + f'[{instr.address:08x}]\t{instrBytes}' + '\t' * depth + f'{instr.mnemonic}\t{instr.op_str}')
def _disasmBytes(self, cs, ks, disasmData, startOffset, length, callback, maxDepth, depth):
if depth > maxDepth:
return 0
data = disasmData[startOffset:startOffset + length]
for instr in cs.disasm(data, startOffset):
self.printInstr(instr, depth)
if len(instr.operands) == 1:
operand = instr.operands[0]
if operand.type == capstone.CS_OP_IMM:
logger.debug('\t' * (depth+1) + f' -> OP_IMM: 0x{operand.value.imm:X}')
logger.debug('')
if callback:
out = callback(cs, ks, disasmData, startOffset, instr, operand, depth)
if out != 0:
return out
if depth + 1 <= maxDepth:
out = self._disasmBytes(cs, ks, disasmData, operand.value.imm, length, callback, maxDepth, depth + 1)
return out
if not callback:
return 1
return 0