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chromium / external / pefile / 3ea8f2a8d6b9ef2afd407dcc089e3084b4e24061 / . / pefile.py
blob: 2598bcc56d9b401f53580a94f0fdc63bd6079f14 [file] [log] [blame]
# -*- coding: Latin-1 -*-
"""pefile, Portable Executable reader module
All the PE file basic structures are available with their default names
as attributes of the instance returned.
Processed elements such as the import table are made available with lowercase
names, to differentiate them from the upper case basic structure names.
pefile has been tested against the limits of valid PE headers, that is, malware.
Lots of packed malware attempt to abuse the format way beyond its standard use.
To the best of my knowledge most of the abuses are handled gracefully.
Copyright (c) 2005, 2006, 2007, 2008, 2009 Ero Carrera <ero@dkbza.org>
All rights reserved.
For detailed copyright information see the file COPYING in
the root of the distribution archive.
"""
__revision__ = "$LastChangedRevision$"
__author__ = 'Ero Carrera'
__version__ = '1.2.10-%d' % int( __revision__[21:-2] )
__contact__ = 'ero@dkbza.org'
import os
import struct
import time
import math
import re
import exceptions
import string
import array
sha1, sha256, sha512, md5 = None, None, None, None
try:
import hashlib
sha1 = hashlib.sha1
sha256 = hashlib.sha256
sha512 = hashlib.sha512
md5 = hashlib.md5
except ImportError:
try:
import sha
sha1 = sha.new
except ImportError:
pass
try:
import md5
md5 = md5.new
except ImportError:
pass
fast_load = False
IMAGE_DOS_SIGNATURE = 0x5A4D
IMAGE_OS2_SIGNATURE = 0x454E
IMAGE_OS2_SIGNATURE_LE = 0x454C
IMAGE_VXD_SIGNATURE = 0x454C
IMAGE_NT_SIGNATURE = 0x00004550
IMAGE_NUMBEROF_DIRECTORY_ENTRIES= 16
IMAGE_ORDINAL_FLAG = 0x80000000L
IMAGE_ORDINAL_FLAG64 = 0x8000000000000000L
OPTIONAL_HEADER_MAGIC_PE = 0x10b
OPTIONAL_HEADER_MAGIC_PE_PLUS = 0x20b
directory_entry_types = [
('IMAGE_DIRECTORY_ENTRY_EXPORT', 0),
('IMAGE_DIRECTORY_ENTRY_IMPORT', 1),
('IMAGE_DIRECTORY_ENTRY_RESOURCE', 2),
('IMAGE_DIRECTORY_ENTRY_EXCEPTION', 3),
('IMAGE_DIRECTORY_ENTRY_SECURITY', 4),
('IMAGE_DIRECTORY_ENTRY_BASERELOC', 5),
('IMAGE_DIRECTORY_ENTRY_DEBUG', 6),
('IMAGE_DIRECTORY_ENTRY_COPYRIGHT', 7),
('IMAGE_DIRECTORY_ENTRY_GLOBALPTR', 8),
('IMAGE_DIRECTORY_ENTRY_TLS', 9),
('IMAGE_DIRECTORY_ENTRY_LOAD_CONFIG', 10),
('IMAGE_DIRECTORY_ENTRY_BOUND_IMPORT', 11),
('IMAGE_DIRECTORY_ENTRY_IAT', 12),
('IMAGE_DIRECTORY_ENTRY_DELAY_IMPORT', 13),
('IMAGE_DIRECTORY_ENTRY_COM_DESCRIPTOR',14),
('IMAGE_DIRECTORY_ENTRY_RESERVED', 15) ]
DIRECTORY_ENTRY = dict([(e[1], e[0]) for e in directory_entry_types]+directory_entry_types)
image_characteristics = [
('IMAGE_FILE_RELOCS_STRIPPED', 0x0001),
('IMAGE_FILE_EXECUTABLE_IMAGE', 0x0002),
('IMAGE_FILE_LINE_NUMS_STRIPPED', 0x0004),
('IMAGE_FILE_LOCAL_SYMS_STRIPPED', 0x0008),
('IMAGE_FILE_AGGRESIVE_WS_TRIM', 0x0010),
('IMAGE_FILE_LARGE_ADDRESS_AWARE', 0x0020),
('IMAGE_FILE_16BIT_MACHINE', 0x0040),
('IMAGE_FILE_BYTES_REVERSED_LO', 0x0080),
('IMAGE_FILE_32BIT_MACHINE', 0x0100),
('IMAGE_FILE_DEBUG_STRIPPED', 0x0200),
('IMAGE_FILE_REMOVABLE_RUN_FROM_SWAP', 0x0400),
('IMAGE_FILE_NET_RUN_FROM_SWAP', 0x0800),
('IMAGE_FILE_SYSTEM', 0x1000),
('IMAGE_FILE_DLL', 0x2000),
('IMAGE_FILE_UP_SYSTEM_ONLY', 0x4000),
('IMAGE_FILE_BYTES_REVERSED_HI', 0x8000) ]
IMAGE_CHARACTERISTICS = dict([(e[1], e[0]) for e in
image_characteristics]+image_characteristics)
section_characteristics = [
('IMAGE_SCN_CNT_CODE', 0x00000020),
('IMAGE_SCN_CNT_INITIALIZED_DATA', 0x00000040),
('IMAGE_SCN_CNT_UNINITIALIZED_DATA', 0x00000080),
('IMAGE_SCN_LNK_OTHER', 0x00000100),
('IMAGE_SCN_LNK_INFO', 0x00000200),
('IMAGE_SCN_LNK_REMOVE', 0x00000800),
('IMAGE_SCN_LNK_COMDAT', 0x00001000),
('IMAGE_SCN_MEM_FARDATA', 0x00008000),
('IMAGE_SCN_MEM_PURGEABLE', 0x00020000),
('IMAGE_SCN_MEM_16BIT', 0x00020000),
('IMAGE_SCN_MEM_LOCKED', 0x00040000),
('IMAGE_SCN_MEM_PRELOAD', 0x00080000),
('IMAGE_SCN_ALIGN_1BYTES', 0x00100000),
('IMAGE_SCN_ALIGN_2BYTES', 0x00200000),
('IMAGE_SCN_ALIGN_4BYTES', 0x00300000),
('IMAGE_SCN_ALIGN_8BYTES', 0x00400000),
('IMAGE_SCN_ALIGN_16BYTES', 0x00500000),
('IMAGE_SCN_ALIGN_32BYTES', 0x00600000),
('IMAGE_SCN_ALIGN_64BYTES', 0x00700000),
('IMAGE_SCN_ALIGN_128BYTES', 0x00800000),
('IMAGE_SCN_ALIGN_256BYTES', 0x00900000),
('IMAGE_SCN_ALIGN_512BYTES', 0x00A00000),
('IMAGE_SCN_ALIGN_1024BYTES', 0x00B00000),
('IMAGE_SCN_ALIGN_2048BYTES', 0x00C00000),
('IMAGE_SCN_ALIGN_4096BYTES', 0x00D00000),
('IMAGE_SCN_ALIGN_8192BYTES', 0x00E00000),
('IMAGE_SCN_ALIGN_MASK', 0x00F00000),
('IMAGE_SCN_LNK_NRELOC_OVFL', 0x01000000),
('IMAGE_SCN_MEM_DISCARDABLE', 0x02000000),
('IMAGE_SCN_MEM_NOT_CACHED', 0x04000000),
('IMAGE_SCN_MEM_NOT_PAGED', 0x08000000),
('IMAGE_SCN_MEM_SHARED', 0x10000000),
('IMAGE_SCN_MEM_EXECUTE', 0x20000000),
('IMAGE_SCN_MEM_READ', 0x40000000),
('IMAGE_SCN_MEM_WRITE', 0x80000000L) ]
SECTION_CHARACTERISTICS = dict([(e[1], e[0]) for e in
section_characteristics]+section_characteristics)
debug_types = [
('IMAGE_DEBUG_TYPE_UNKNOWN', 0),
('IMAGE_DEBUG_TYPE_COFF', 1),
('IMAGE_DEBUG_TYPE_CODEVIEW', 2),
('IMAGE_DEBUG_TYPE_FPO', 3),
('IMAGE_DEBUG_TYPE_MISC', 4),
('IMAGE_DEBUG_TYPE_EXCEPTION', 5),
('IMAGE_DEBUG_TYPE_FIXUP', 6),
('IMAGE_DEBUG_TYPE_OMAP_TO_SRC', 7),
('IMAGE_DEBUG_TYPE_OMAP_FROM_SRC', 8),
('IMAGE_DEBUG_TYPE_BORLAND', 9),
('IMAGE_DEBUG_TYPE_RESERVED10', 10) ]
DEBUG_TYPE = dict([(e[1], e[0]) for e in debug_types]+debug_types)
subsystem_types = [
('IMAGE_SUBSYSTEM_UNKNOWN', 0),
('IMAGE_SUBSYSTEM_NATIVE', 1),
('IMAGE_SUBSYSTEM_WINDOWS_GUI', 2),
('IMAGE_SUBSYSTEM_WINDOWS_CUI', 3),
('IMAGE_SUBSYSTEM_OS2_CUI', 5),
('IMAGE_SUBSYSTEM_POSIX_CUI', 7),
('IMAGE_SUBSYSTEM_WINDOWS_CE_GUI', 9),
('IMAGE_SUBSYSTEM_EFI_APPLICATION', 10),
('IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER', 11),
('IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER', 12),
('IMAGE_SUBSYSTEM_EFI_ROM', 13),
('IMAGE_SUBSYSTEM_XBOX', 14)]
SUBSYSTEM_TYPE = dict([(e[1], e[0]) for e in subsystem_types]+subsystem_types)
machine_types = [
('IMAGE_FILE_MACHINE_UNKNOWN', 0),
('IMAGE_FILE_MACHINE_AM33', 0x1d3),
('IMAGE_FILE_MACHINE_AMD64', 0x8664),
('IMAGE_FILE_MACHINE_ARM', 0x1c0),
('IMAGE_FILE_MACHINE_EBC', 0xebc),
('IMAGE_FILE_MACHINE_I386', 0x14c),
('IMAGE_FILE_MACHINE_IA64', 0x200),
('IMAGE_FILE_MACHINE_MR32', 0x9041),
('IMAGE_FILE_MACHINE_MIPS16', 0x266),
('IMAGE_FILE_MACHINE_MIPSFPU', 0x366),
('IMAGE_FILE_MACHINE_MIPSFPU16',0x466),
('IMAGE_FILE_MACHINE_POWERPC', 0x1f0),
('IMAGE_FILE_MACHINE_POWERPCFP',0x1f1),
('IMAGE_FILE_MACHINE_R4000', 0x166),
('IMAGE_FILE_MACHINE_SH3', 0x1a2),
('IMAGE_FILE_MACHINE_SH3DSP', 0x1a3),
('IMAGE_FILE_MACHINE_SH4', 0x1a6),
('IMAGE_FILE_MACHINE_SH5', 0x1a8),
('IMAGE_FILE_MACHINE_THUMB', 0x1c2),
('IMAGE_FILE_MACHINE_WCEMIPSV2',0x169),
]
MACHINE_TYPE = dict([(e[1], e[0]) for e in machine_types]+machine_types)
relocation_types = [
('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_MIPS_JMPADDR', 5),
('IMAGE_REL_BASED_SECTION', 6),
('IMAGE_REL_BASED_REL', 7),
('IMAGE_REL_BASED_MIPS_JMPADDR16', 9),
('IMAGE_REL_BASED_IA64_IMM64', 9),
('IMAGE_REL_BASED_DIR64', 10),
('IMAGE_REL_BASED_HIGH3ADJ', 11) ]
RELOCATION_TYPE = dict([(e[1], e[0]) for e in relocation_types]+relocation_types)
dll_characteristics = [
('IMAGE_DLL_CHARACTERISTICS_RESERVED_0x0001', 0x0001),
('IMAGE_DLL_CHARACTERISTICS_RESERVED_0x0002', 0x0002),
('IMAGE_DLL_CHARACTERISTICS_RESERVED_0x0004', 0x0004),
('IMAGE_DLL_CHARACTERISTICS_RESERVED_0x0008', 0x0008),
('IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE', 0x0040),
('IMAGE_DLL_CHARACTERISTICS_FORCE_INTEGRITY', 0x0080),
('IMAGE_DLL_CHARACTERISTICS_NX_COMPAT', 0x0100),
('IMAGE_DLL_CHARACTERISTICS_NO_ISOLATION', 0x0200),
('IMAGE_DLL_CHARACTERISTICS_NO_SEH', 0x0400),
('IMAGE_DLL_CHARACTERISTICS_NO_BIND', 0x0800),
('IMAGE_DLL_CHARACTERISTICS_RESERVED_0x1000', 0x1000),
('IMAGE_DLL_CHARACTERISTICS_WDM_DRIVER', 0x2000),
('IMAGE_DLL_CHARACTERISTICS_TERMINAL_SERVER_AWARE', 0x8000) ]
DLL_CHARACTERISTICS = dict([(e[1], e[0]) for e in dll_characteristics]+dll_characteristics)
# Resource types
resource_type = [
('RT_CURSOR', 1),
('RT_BITMAP', 2),
('RT_ICON', 3),
('RT_MENU', 4),
('RT_DIALOG', 5),
('RT_STRING', 6),
('RT_FONTDIR', 7),
('RT_FONT', 8),
('RT_ACCELERATOR', 9),
('RT_RCDATA', 10),
('RT_MESSAGETABLE', 11),
('RT_GROUP_CURSOR', 12),
('RT_GROUP_ICON', 14),
('RT_VERSION', 16),
('RT_DLGINCLUDE', 17),
('RT_PLUGPLAY', 19),
('RT_VXD', 20),
('RT_ANICURSOR', 21),
('RT_ANIICON', 22),
('RT_HTML', 23),
('RT_MANIFEST', 24) ]
RESOURCE_TYPE = dict([(e[1], e[0]) for e in resource_type]+resource_type)
# Language definitions
lang = [
('LANG_NEUTRAL', 0x00),
('LANG_INVARIANT', 0x7f),
('LANG_AFRIKAANS', 0x36),
('LANG_ALBANIAN', 0x1c),
('LANG_ARABIC', 0x01),
('LANG_ARMENIAN', 0x2b),
('LANG_ASSAMESE', 0x4d),
('LANG_AZERI', 0x2c),
('LANG_BASQUE', 0x2d),
('LANG_BELARUSIAN', 0x23),
('LANG_BENGALI', 0x45),
('LANG_BULGARIAN', 0x02),
('LANG_CATALAN', 0x03),
('LANG_CHINESE', 0x04),
('LANG_CROATIAN', 0x1a),
('LANG_CZECH', 0x05),
('LANG_DANISH', 0x06),
('LANG_DIVEHI', 0x65),
('LANG_DUTCH', 0x13),
('LANG_ENGLISH', 0x09),
('LANG_ESTONIAN', 0x25),
('LANG_FAEROESE', 0x38),
('LANG_FARSI', 0x29),
('LANG_FINNISH', 0x0b),
('LANG_FRENCH', 0x0c),
('LANG_GALICIAN', 0x56),
('LANG_GEORGIAN', 0x37),
('LANG_GERMAN', 0x07),
('LANG_GREEK', 0x08),
('LANG_GUJARATI', 0x47),
('LANG_HEBREW', 0x0d),
('LANG_HINDI', 0x39),
('LANG_HUNGARIAN', 0x0e),
('LANG_ICELANDIC', 0x0f),
('LANG_INDONESIAN', 0x21),
('LANG_ITALIAN', 0x10),
('LANG_JAPANESE', 0x11),
('LANG_KANNADA', 0x4b),
('LANG_KASHMIRI', 0x60),
('LANG_KAZAK', 0x3f),
('LANG_KONKANI', 0x57),
('LANG_KOREAN', 0x12),
('LANG_KYRGYZ', 0x40),
('LANG_LATVIAN', 0x26),
('LANG_LITHUANIAN', 0x27),
('LANG_MACEDONIAN', 0x2f),
('LANG_MALAY', 0x3e),
('LANG_MALAYALAM', 0x4c),
('LANG_MANIPURI', 0x58),
('LANG_MARATHI', 0x4e),
('LANG_MONGOLIAN', 0x50),
('LANG_NEPALI', 0x61),
('LANG_NORWEGIAN', 0x14),
('LANG_ORIYA', 0x48),
('LANG_POLISH', 0x15),
('LANG_PORTUGUESE', 0x16),
('LANG_PUNJABI', 0x46),
('LANG_ROMANIAN', 0x18),
('LANG_RUSSIAN', 0x19),
('LANG_SANSKRIT', 0x4f),
('LANG_SERBIAN', 0x1a),
('LANG_SINDHI', 0x59),
('LANG_SLOVAK', 0x1b),
('LANG_SLOVENIAN', 0x24),
('LANG_SPANISH', 0x0a),
('LANG_SWAHILI', 0x41),
('LANG_SWEDISH', 0x1d),
('LANG_SYRIAC', 0x5a),
('LANG_TAMIL', 0x49),
('LANG_TATAR', 0x44),
('LANG_TELUGU', 0x4a),
('LANG_THAI', 0x1e),
('LANG_TURKISH', 0x1f),
('LANG_UKRAINIAN', 0x22),
('LANG_URDU', 0x20),
('LANG_UZBEK', 0x43),
('LANG_VIETNAMESE', 0x2a),
('LANG_GAELIC', 0x3c),
('LANG_MALTESE', 0x3a),
('LANG_MAORI', 0x28),
('LANG_RHAETO_ROMANCE',0x17),
('LANG_SAAMI', 0x3b),
('LANG_SORBIAN', 0x2e),
('LANG_SUTU', 0x30),
('LANG_TSONGA', 0x31),
('LANG_TSWANA', 0x32),
('LANG_VENDA', 0x33),
('LANG_XHOSA', 0x34),
('LANG_ZULU', 0x35),
('LANG_ESPERANTO', 0x8f),
('LANG_WALON', 0x90),
('LANG_CORNISH', 0x91),
('LANG_WELSH', 0x92),
('LANG_BRETON', 0x93) ]
LANG = dict(lang+[(e[1], e[0]) for e in lang])
# Sublanguage definitions
sublang = [
('SUBLANG_NEUTRAL', 0x00),
('SUBLANG_DEFAULT', 0x01),
('SUBLANG_SYS_DEFAULT', 0x02),
('SUBLANG_ARABIC_SAUDI_ARABIA', 0x01),
('SUBLANG_ARABIC_IRAQ', 0x02),
('SUBLANG_ARABIC_EGYPT', 0x03),
('SUBLANG_ARABIC_LIBYA', 0x04),
('SUBLANG_ARABIC_ALGERIA', 0x05),
('SUBLANG_ARABIC_MOROCCO', 0x06),
('SUBLANG_ARABIC_TUNISIA', 0x07),
('SUBLANG_ARABIC_OMAN', 0x08),
('SUBLANG_ARABIC_YEMEN', 0x09),
('SUBLANG_ARABIC_SYRIA', 0x0a),
('SUBLANG_ARABIC_JORDAN', 0x0b),
('SUBLANG_ARABIC_LEBANON', 0x0c),
('SUBLANG_ARABIC_KUWAIT', 0x0d),
('SUBLANG_ARABIC_UAE', 0x0e),
('SUBLANG_ARABIC_BAHRAIN', 0x0f),
('SUBLANG_ARABIC_QATAR', 0x10),
('SUBLANG_AZERI_LATIN', 0x01),
('SUBLANG_AZERI_CYRILLIC', 0x02),
('SUBLANG_CHINESE_TRADITIONAL', 0x01),
('SUBLANG_CHINESE_SIMPLIFIED', 0x02),
('SUBLANG_CHINESE_HONGKONG', 0x03),
('SUBLANG_CHINESE_SINGAPORE', 0x04),
('SUBLANG_CHINESE_MACAU', 0x05),
('SUBLANG_DUTCH', 0x01),
('SUBLANG_DUTCH_BELGIAN', 0x02),
('SUBLANG_ENGLISH_US', 0x01),
('SUBLANG_ENGLISH_UK', 0x02),
('SUBLANG_ENGLISH_AUS', 0x03),
('SUBLANG_ENGLISH_CAN', 0x04),
('SUBLANG_ENGLISH_NZ', 0x05),
('SUBLANG_ENGLISH_EIRE', 0x06),
('SUBLANG_ENGLISH_SOUTH_AFRICA', 0x07),
('SUBLANG_ENGLISH_JAMAICA', 0x08),
('SUBLANG_ENGLISH_CARIBBEAN', 0x09),
('SUBLANG_ENGLISH_BELIZE', 0x0a),
('SUBLANG_ENGLISH_TRINIDAD', 0x0b),
('SUBLANG_ENGLISH_ZIMBABWE', 0x0c),
('SUBLANG_ENGLISH_PHILIPPINES', 0x0d),
('SUBLANG_FRENCH', 0x01),
('SUBLANG_FRENCH_BELGIAN', 0x02),
('SUBLANG_FRENCH_CANADIAN', 0x03),
('SUBLANG_FRENCH_SWISS', 0x04),
('SUBLANG_FRENCH_LUXEMBOURG', 0x05),
('SUBLANG_FRENCH_MONACO', 0x06),
('SUBLANG_GERMAN', 0x01),
('SUBLANG_GERMAN_SWISS', 0x02),
('SUBLANG_GERMAN_AUSTRIAN', 0x03),
('SUBLANG_GERMAN_LUXEMBOURG', 0x04),
('SUBLANG_GERMAN_LIECHTENSTEIN', 0x05),
('SUBLANG_ITALIAN', 0x01),
('SUBLANG_ITALIAN_SWISS', 0x02),
('SUBLANG_KASHMIRI_SASIA', 0x02),
('SUBLANG_KASHMIRI_INDIA', 0x02),
('SUBLANG_KOREAN', 0x01),
('SUBLANG_LITHUANIAN', 0x01),
('SUBLANG_MALAY_MALAYSIA', 0x01),
('SUBLANG_MALAY_BRUNEI_DARUSSALAM', 0x02),
('SUBLANG_NEPALI_INDIA', 0x02),
('SUBLANG_NORWEGIAN_BOKMAL', 0x01),
('SUBLANG_NORWEGIAN_NYNORSK', 0x02),
('SUBLANG_PORTUGUESE', 0x02),
('SUBLANG_PORTUGUESE_BRAZILIAN', 0x01),
('SUBLANG_SERBIAN_LATIN', 0x02),
('SUBLANG_SERBIAN_CYRILLIC', 0x03),
('SUBLANG_SPANISH', 0x01),
('SUBLANG_SPANISH_MEXICAN', 0x02),
('SUBLANG_SPANISH_MODERN', 0x03),
('SUBLANG_SPANISH_GUATEMALA', 0x04),
('SUBLANG_SPANISH_COSTA_RICA', 0x05),
('SUBLANG_SPANISH_PANAMA', 0x06),
('SUBLANG_SPANISH_DOMINICAN_REPUBLIC', 0x07),
('SUBLANG_SPANISH_VENEZUELA', 0x08),
('SUBLANG_SPANISH_COLOMBIA', 0x09),
('SUBLANG_SPANISH_PERU', 0x0a),
('SUBLANG_SPANISH_ARGENTINA', 0x0b),
('SUBLANG_SPANISH_ECUADOR', 0x0c),
('SUBLANG_SPANISH_CHILE', 0x0d),
('SUBLANG_SPANISH_URUGUAY', 0x0e),
('SUBLANG_SPANISH_PARAGUAY', 0x0f),
('SUBLANG_SPANISH_BOLIVIA', 0x10),
('SUBLANG_SPANISH_EL_SALVADOR', 0x11),
('SUBLANG_SPANISH_HONDURAS', 0x12),
('SUBLANG_SPANISH_NICARAGUA', 0x13),
('SUBLANG_SPANISH_PUERTO_RICO', 0x14),
('SUBLANG_SWEDISH', 0x01),
('SUBLANG_SWEDISH_FINLAND', 0x02),
('SUBLANG_URDU_PAKISTAN', 0x01),
('SUBLANG_URDU_INDIA', 0x02),
('SUBLANG_UZBEK_LATIN', 0x01),
('SUBLANG_UZBEK_CYRILLIC', 0x02),
('SUBLANG_DUTCH_SURINAM', 0x03),
('SUBLANG_ROMANIAN', 0x01),
('SUBLANG_ROMANIAN_MOLDAVIA', 0x02),
('SUBLANG_RUSSIAN', 0x01),
('SUBLANG_RUSSIAN_MOLDAVIA', 0x02),
('SUBLANG_CROATIAN', 0x01),
('SUBLANG_LITHUANIAN_CLASSIC', 0x02),
('SUBLANG_GAELIC', 0x01),
('SUBLANG_GAELIC_SCOTTISH', 0x02),
('SUBLANG_GAELIC_MANX', 0x03) ]
SUBLANG = dict(sublang+[(e[1], e[0]) for e in sublang])
class UnicodeStringWrapperPostProcessor:
"""This class attemps to help the process of identifying strings
that might be plain Unicode or Pascal. A list of strings will be
wrapped on it with the hope the overlappings will help make the
decission about their type."""
def __init__(self, pe, rva_ptr):
self.pe = pe
self.rva_ptr = rva_ptr
self.string = None
def get_rva(self):
"""Get the RVA of the string."""
return self.rva_ptr
def __str__(self):
"""Return the escaped ASCII representation of the string."""
def convert_char(char):
if char in string.printable:
return char
else:
return r'\x%02x' % ord(char)
if self.string:
return ''.join([convert_char(c) for c in self.string])
return ''
def invalidate(self):
"""Make this instance None, to express it's no known string type."""
self = None
def render_pascal_16(self):
self.string = self.pe.get_string_u_at_rva(
self.rva_ptr+2,
max_length=self.__get_pascal_16_length())
def ask_pascal_16(self, next_rva_ptr):
"""The next RVA is taken to be the one immediately following this one.
Such RVA could indicate the natural end of the string and will be checked
with the possible length contained in the first word.
"""
length = self.__get_pascal_16_length()
if length == (next_rva_ptr - (self.rva_ptr+2)) / 2:
self.length = length
return True
return False
def __get_pascal_16_length(self):
return self.__get_word_value_at_rva(self.rva_ptr)
def __get_word_value_at_rva(self, rva):
try:
data = self.pe.get_data(self.rva_ptr, 2)
except PEFormatError, e:
return False
if len(data)<2:
return False
return struct.unpack('<H', data)[0]
#def render_pascal_8(self):
# """"""
def ask_unicode_16(self, next_rva_ptr):
"""The next RVA is taken to be the one immediately following this one.
Such RVA could indicate the natural end of the string and will be checked
to see if there's a Unicode NULL character there.
"""
if self.__get_word_value_at_rva(next_rva_ptr-2) == 0:
self.length = next_rva_ptr - self.rva_ptr
return True
return False
def render_unicode_16(self):
""""""
self.string = self.pe.get_string_u_at_rva(self.rva_ptr)
class PEFormatError(Exception):
"""Generic PE format error exception."""
def __init__(self, value):
self.value = value
def __str__(self):
return repr(self.value)
class Dump:
"""Convenience class for dumping the PE information."""
def __init__(self):
self.text = list()
def add_lines(self, txt, indent=0):
"""Adds a list of lines.
The list can be indented with the optional argument 'indent'.
"""
for line in txt:
self.add_line(line, indent)
def add_line(self, txt, indent=0):
"""Adds a line.
The line can be indented with the optional argument 'indent'.
"""
self.add(txt+'\n', indent)
def add(self, txt, indent=0):
"""Adds some text, no newline will be appended.
The text can be indented with the optional argument 'indent'.
"""
if isinstance(txt, unicode):
try:
txt = str(txt)
except UnicodeEncodeError:
s = []
for c in txt:
try:
s.append(str(c))
except UnicodeEncodeError:
s.append(repr(c))
txt = ''.join(s)
self.text.append( ' '*indent + txt )
def add_header(self, txt):
"""Adds a header element."""
self.add_line('-'*10+txt+'-'*10+'\n')
def add_newline(self):
"""Adds a newline."""
self.text.append( '\n' )
def get_text(self):
"""Get the text in its current state."""
return ''.join( self.text )
class Structure:
"""Prepare structure object to extract members from data.
Format is a list containing definitions for the elements
of the structure.
"""
def __init__(self, format, name=None, file_offset=None):
# Format is forced little endian, for big endian non Intel platforms
self.__format__ = '<'
self.__keys__ = []
#self.values = {}
self.__format_length__ = 0
self.__set_format__(format[1])
self.__all_zeroes__ = False
self.__unpacked_data_elms__ = None
self.__file_offset__ = file_offset
if name:
self.name = name
else:
self.name = format[0]
def __get_format__(self):
return self.__format__
def get_file_offset(self):
return self.__file_offset__
def set_file_offset(self, offset):
self.__file_offset__ = offset
def all_zeroes(self):
"""Returns true is the unpacked data is all zeroes."""
return self.__all_zeroes__
def __set_format__(self, format):
for elm in format:
if ',' in elm:
elm_type, elm_name = elm.split(',', 1)
self.__format__ += elm_type
elm_names = elm_name.split(',')
names = []
for elm_name in elm_names:
if elm_name in self.__keys__:
search_list = [x[:len(elm_name)] for x in self.__keys__]
occ_count = search_list.count(elm_name)
elm_name = elm_name+'_'+str(occ_count)
names.append(elm_name)
# Some PE header structures have unions on them, so a certain
# value might have different names, so each key has a list of
# all the possible members referring to the data.
self.__keys__.append(names)
self.__format_length__ = struct.calcsize(self.__format__)
def sizeof(self):
"""Return size of the structure."""
return self.__format_length__
def __unpack__(self, data):
if len(data) > self.__format_length__:
data = data[:self.__format_length__]
# OC Patch:
# Some malware have incorrect header lengths.
# Fail gracefully if this occurs
# Buggy malware: a29b0118af8b7408444df81701ad5a7f
#
elif len(data)<self.__format_length__:
raise PEFormatError('Data length less than expected header length.')
if data.count(chr(0)) == len(data):
self.__all_zeroes__ = True
self.__unpacked_data_elms__ = struct.unpack(self.__format__, data)
for i in xrange(len(self.__unpacked_data_elms__)):
for key in self.__keys__[i]:
#self.values[key] = self.__unpacked_data_elms__[i]
setattr(self, key, self.__unpacked_data_elms__[i])
def __pack__(self):
new_values = []
for i in xrange(len(self.__unpacked_data_elms__)):
for key in self.__keys__[i]:
new_val = getattr(self, key)
old_val = self.__unpacked_data_elms__[i]
# In the case of Unions, when the first changed value
# is picked the loop is exited
if new_val != old_val:
break
new_values.append(new_val)
return struct.pack(self.__format__, *new_values)
def __str__(self):
return '\n'.join( self.dump() )
def __repr__(self):
return '<Structure: %s>' % (' '.join( [' '.join(s.split()) for s in self.dump()] ))
def dump(self, indentation=0):
"""Returns a string representation of the structure."""
dump = []
dump.append('[%s]' % self.name)
# Refer to the __set_format__ method for an explanation
# of the following construct.
for keys in self.__keys__:
for key in keys:
val = getattr(self, key)
if isinstance(val, int) or isinstance(val, long):
val_str = '0x%-8X' % (val)
if key == 'TimeDateStamp' or key == 'dwTimeStamp':
try:
val_str += ' [%s UTC]' % time.asctime(time.gmtime(val))
except exceptions.ValueError, e:
val_str += ' [INVALID TIME]'
else:
val_str = ''.join(filter(lambda c:c != '\0', str(val)))
dump.append('%-30s %s' % (key+':', val_str))
return dump
class SectionStructure(Structure):
"""Convenience section handling class."""
def get_data(self, start, length=None):
"""Get data chunk from a section.
Allows to query data from the section by passing the
addresses where the PE file would be loaded by default.
It is then possible to retrieve code and data by its real
addresses as it would be if loaded.
"""
offset = start - self.VirtualAddress
if length:
end = offset+length
else:
end = len(self.data)
return self.data[offset:end]
def get_rva_from_offset(self, offset):
return offset - self.PointerToRawData + self.VirtualAddress
def get_offset_from_rva(self, rva):
return (rva - self.VirtualAddress) + self.PointerToRawData
def contains_offset(self, offset):
"""Check whether the section contains the file offset provided."""
if not self.PointerToRawData:
# bss and other sections containing only uninitialized data must have 0
# and do not take space in the file
return False
return self.PointerToRawData <= offset < self.PointerToRawData + self.SizeOfRawData
def contains_rva(self, rva):
"""Check whether the section contains the address provided."""
# PECOFF documentation v8 says:
# The total size of the section when loaded into memory.
# If this value is greater than SizeOfRawData, the section is zero-padded.
# This field is valid only for executable images and should be set to zero
# for object files.
if len(self.data) < self.SizeOfRawData:
size = self.Misc_VirtualSize
else:
size = max(self.SizeOfRawData, self.Misc_VirtualSize)
return self.VirtualAddress <= rva < self.VirtualAddress + size
def contains(self, rva):
#print "DEPRECATION WARNING: you should use contains_rva() instead of contains()"
return self.contains_rva(rva)
def set_data(self, data):
"""Set the data belonging to the section."""
self.data = data
def get_entropy(self):
"""Calculate and return the entropy for the section."""
return self.entropy_H( self.data )
def get_hash_sha1(self):
"""Get the SHA-1 hex-digest of the section's data."""
if sha1 is not None:
return sha1( self.data ).hexdigest()
def get_hash_sha256(self):
"""Get the SHA-256 hex-digest of the section's data."""
if sha256 is not None:
return sha256( self.data ).hexdigest()
def get_hash_sha512(self):
"""Get the SHA-512 hex-digest of the section's data."""
if sha512 is not None:
return sha512( self.data ).hexdigest()
def get_hash_md5(self):
"""Get the MD5 hex-digest of the section's data."""
if md5 is not None:
return md5( self.data ).hexdigest()
def entropy_H(self, data):
"""Calculate the entropy of a chunk of data."""
if len(data) == 0:
return 0.0
occurences = array.array('L', [0]*256)
for x in data:
occurences[ord(x)] += 1
entropy = 0
for x in occurences:
if x:
p_x = float(x) / len(data)
entropy -= p_x*math.log(p_x, 2)
return entropy
class DataContainer:
"""Generic data container."""
def __init__(self, **args):
for key, value in args.items():
setattr(self, key, value)
class ImportDescData(DataContainer):
"""Holds import descriptor information.
dll: name of the imported DLL
imports: list of imported symbols (ImportData instances)
struct: IMAGE_IMPORT_DESCRIPTOR sctruture
"""
class ImportData(DataContainer):
"""Holds imported symbol's information.
ordinal: Ordinal of the symbol
name: Name of the symbol
bound: If the symbol is bound, this contains
the address.
"""
class ExportDirData(DataContainer):
"""Holds export directory information.
struct: IMAGE_EXPORT_DIRECTORY structure
symbols: list of exported symbols (ExportData instances)
"""
class ExportData(DataContainer):
"""Holds exported symbols' information.
ordinal: ordinal of the symbol
address: address of the symbol
name: name of the symbol (None if the symbol is
exported by ordinal only)
forwarder: if the symbol is forwarded it will
contain the name of the target symbol,
None otherwise.
"""
class ResourceDirData(DataContainer):
"""Holds resource directory information.
struct: IMAGE_RESOURCE_DIRECTORY structure
entries: list of entries (ResourceDirEntryData instances)
"""
class ResourceDirEntryData(DataContainer):
"""Holds resource directory entry data.
struct: IMAGE_RESOURCE_DIRECTORY_ENTRY structure
name: If the resource is identified by name this
attribute will contain the name string. None
otherwise. If identified by id, the id is
availabe at 'struct.Id'
id: the id, also in struct.Id
directory: If this entry has a lower level directory
this attribute will point to the
ResourceDirData instance representing it.
data: If this entry has no futher lower directories
and points to the actual resource data, this
attribute will reference the corresponding
ResourceDataEntryData instance.
(Either of the 'directory' or 'data' attribute will exist,
but not both.)
"""
class ResourceDataEntryData(DataContainer):
"""Holds resource data entry information.
struct: IMAGE_RESOURCE_DATA_ENTRY structure
lang: Primary language ID
sublang: Sublanguage ID
"""
class DebugData(DataContainer):
"""Holds debug information.
struct: IMAGE_DEBUG_DIRECTORY structure
"""
class BaseRelocationData(DataContainer):
"""Holds base relocation information.
struct: IMAGE_BASE_RELOCATION structure
entries: list of relocation data (RelocationData instances)
"""
class RelocationData(DataContainer):
"""Holds relocation information.
type: Type of relocation
The type string is can be obtained by
RELOCATION_TYPE[type]
rva: RVA of the relocation
"""
class TlsData(DataContainer):
"""Holds TLS information.
struct: IMAGE_TLS_DIRECTORY structure
"""
class BoundImportDescData(DataContainer):
"""Holds bound import descriptor data.
This directory entry will provide with information on the
DLLs this PE files has been bound to (if bound at all).
The structure will contain the name and timestamp of the
DLL at the time of binding so that the loader can know
whether it differs from the one currently present in the
system and must, therefore, re-bind the PE's imports.
struct: IMAGE_BOUND_IMPORT_DESCRIPTOR structure
name: DLL name
entries: list of entries (BoundImportRefData instances)
the entries will exist if this DLL has forwarded
symbols. If so, the destination DLL will have an
entry in this list.
"""
class BoundImportRefData(DataContainer):
"""Holds bound import forwader reference data.
Contains the same information as the bound descriptor but
for forwarded DLLs, if any.
struct: IMAGE_BOUND_FORWARDER_REF structure
name: dll name
"""
class PE:
"""A Portable Executable representation.
This class provides access to most of the information in a PE file.
It expects to be supplied the name of the file to load or PE data
to process and an optional argument 'fast_load' (False by default)
which controls whether to load all the directories information,
which can be quite time consuming.
pe = pefile.PE('module.dll')
pe = pefile.PE(name='module.dll')
would load 'module.dll' and process it. If the data would be already
available in a buffer the same could be achieved with:
pe = pefile.PE(data=module_dll_data)
The "fast_load" can be set to a default by setting its value in the
module itself by means,for instance, of a "pefile.fast_load = True".
That will make all the subsequent instances not to load the
whole PE structure. The "full_load" method can be used to parse
the missing data at a later stage.
Basic headers information will be available in the attributes:
DOS_HEADER
NT_HEADERS
FILE_HEADER
OPTIONAL_HEADER
All of them will contain among their attrbitues the members of the
corresponding structures as defined in WINNT.H
The raw data corresponding to the header (from the beginning of the
file up to the start of the first section) will be avaiable in the
instance's attribute 'header' as a string.
The sections will be available as a list in the 'sections' attribute.
Each entry will contain as attributes all the structure's members.
Directory entries will be available as attributes (if they exist):
(no other entries are processed at this point)
DIRECTORY_ENTRY_IMPORT (list of ImportDescData instances)
DIRECTORY_ENTRY_EXPORT (ExportDirData instance)
DIRECTORY_ENTRY_RESOURCE (ResourceDirData instance)
DIRECTORY_ENTRY_DEBUG (list of DebugData instances)
DIRECTORY_ENTRY_BASERELOC (list of BaseRelocationData instances)
DIRECTORY_ENTRY_TLS
DIRECTORY_ENTRY_BOUND_IMPORT (list of BoundImportData instances)
The following dictionary attributes provide ways of mapping different
constants. They will accept the numeric value and return the string
representation and the opposite, feed in the string and get the
numeric constant:
DIRECTORY_ENTRY
IMAGE_CHARACTERISTICS
SECTION_CHARACTERISTICS
DEBUG_TYPE
SUBSYSTEM_TYPE
MACHINE_TYPE
RELOCATION_TYPE
RESOURCE_TYPE
LANG
SUBLANG
"""
#
# Format specifications for PE structures.
#
__IMAGE_DOS_HEADER_format__ = ('IMAGE_DOS_HEADER',
('H,e_magic', 'H,e_cblp', 'H,e_cp',
'H,e_crlc', 'H,e_cparhdr', 'H,e_minalloc',
'H,e_maxalloc', 'H,e_ss', 'H,e_sp', 'H,e_csum',
'H,e_ip', 'H,e_cs', 'H,e_lfarlc', 'H,e_ovno', '8s,e_res',
'H,e_oemid', 'H,e_oeminfo', '20s,e_res2',
'L,e_lfanew'))
__IMAGE_FILE_HEADER_format__ = ('IMAGE_FILE_HEADER',
('H,Machine', 'H,NumberOfSections',
'L,TimeDateStamp', 'L,PointerToSymbolTable',
'L,NumberOfSymbols', 'H,SizeOfOptionalHeader',
'H,Characteristics'))
__IMAGE_DATA_DIRECTORY_format__ = ('IMAGE_DATA_DIRECTORY',
('L,VirtualAddress', 'L,Size'))
__IMAGE_OPTIONAL_HEADER_format__ = ('IMAGE_OPTIONAL_HEADER',
('H,Magic', 'B,MajorLinkerVersion',
'B,MinorLinkerVersion', 'L,SizeOfCode',
'L,SizeOfInitializedData', 'L,SizeOfUninitializedData',
'L,AddressOfEntryPoint', 'L,BaseOfCode', 'L,BaseOfData',
'L,ImageBase', 'L,SectionAlignment', 'L,FileAlignment',
'H,MajorOperatingSystemVersion', 'H,MinorOperatingSystemVersion',
'H,MajorImageVersion', 'H,MinorImageVersion',
'H,MajorSubsystemVersion', 'H,MinorSubsystemVersion',
'L,Reserved1', 'L,SizeOfImage', 'L,SizeOfHeaders',
'L,CheckSum', 'H,Subsystem', 'H,DllCharacteristics',
'L,SizeOfStackReserve', 'L,SizeOfStackCommit',
'L,SizeOfHeapReserve', 'L,SizeOfHeapCommit',
'L,LoaderFlags', 'L,NumberOfRvaAndSizes' ))
__IMAGE_OPTIONAL_HEADER64_format__ = ('IMAGE_OPTIONAL_HEADER64',
('H,Magic', 'B,MajorLinkerVersion',
'B,MinorLinkerVersion', 'L,SizeOfCode',
'L,SizeOfInitializedData', 'L,SizeOfUninitializedData',
'L,AddressOfEntryPoint', 'L,BaseOfCode',
'Q,ImageBase', 'L,SectionAlignment', 'L,FileAlignment',
'H,MajorOperatingSystemVersion', 'H,MinorOperatingSystemVersion',
'H,MajorImageVersion', 'H,MinorImageVersion',
'H,MajorSubsystemVersion', 'H,MinorSubsystemVersion',
'L,Reserved1', 'L,SizeOfImage', 'L,SizeOfHeaders',
'L,CheckSum', 'H,Subsystem', 'H,DllCharacteristics',
'Q,SizeOfStackReserve', 'Q,SizeOfStackCommit',
'Q,SizeOfHeapReserve', 'Q,SizeOfHeapCommit',
'L,LoaderFlags', 'L,NumberOfRvaAndSizes' ))
__IMAGE_NT_HEADERS_format__ = ('IMAGE_NT_HEADERS', ('L,Signature',))
__IMAGE_SECTION_HEADER_format__ = ('IMAGE_SECTION_HEADER',
('8s,Name', 'L,Misc,Misc_PhysicalAddress,Misc_VirtualSize',
'L,VirtualAddress', 'L,SizeOfRawData', 'L,PointerToRawData',
'L,PointerToRelocations', 'L,PointerToLinenumbers',
'H,NumberOfRelocations', 'H,NumberOfLinenumbers',
'L,Characteristics'))
__IMAGE_DELAY_IMPORT_DESCRIPTOR_format__ = ('IMAGE_DELAY_IMPORT_DESCRIPTOR',
('L,grAttrs', 'L,szName', 'L,phmod', 'L,pIAT', 'L,pINT',
'L,pBoundIAT', 'L,pUnloadIAT', 'L,dwTimeStamp'))
__IMAGE_IMPORT_DESCRIPTOR_format__ = ('IMAGE_IMPORT_DESCRIPTOR',
('L,OriginalFirstThunk,Characteristics',
'L,TimeDateStamp', 'L,ForwarderChain', 'L,Name', 'L,FirstThunk'))
__IMAGE_EXPORT_DIRECTORY_format__ = ('IMAGE_EXPORT_DIRECTORY',
('L,Characteristics',
'L,TimeDateStamp', 'H,MajorVersion', 'H,MinorVersion', 'L,Name',
'L,Base', 'L,NumberOfFunctions', 'L,NumberOfNames',
'L,AddressOfFunctions', 'L,AddressOfNames', 'L,AddressOfNameOrdinals'))
__IMAGE_RESOURCE_DIRECTORY_format__ = ('IMAGE_RESOURCE_DIRECTORY',
('L,Characteristics',
'L,TimeDateStamp', 'H,MajorVersion', 'H,MinorVersion',
'H,NumberOfNamedEntries', 'H,NumberOfIdEntries'))
__IMAGE_RESOURCE_DIRECTORY_ENTRY_format__ = ('IMAGE_RESOURCE_DIRECTORY_ENTRY',
('L,Name',
'L,OffsetToData'))
__IMAGE_RESOURCE_DATA_ENTRY_format__ = ('IMAGE_RESOURCE_DATA_ENTRY',
('L,OffsetToData', 'L,Size', 'L,CodePage', 'L,Reserved'))
__VS_VERSIONINFO_format__ = ( 'VS_VERSIONINFO',
('H,Length', 'H,ValueLength', 'H,Type' ))
__VS_FIXEDFILEINFO_format__ = ( 'VS_FIXEDFILEINFO',
('L,Signature', 'L,StrucVersion', 'L,FileVersionMS', 'L,FileVersionLS',
'L,ProductVersionMS', 'L,ProductVersionLS', 'L,FileFlagsMask', 'L,FileFlags',
'L,FileOS', 'L,FileType', 'L,FileSubtype', 'L,FileDateMS', 'L,FileDateLS'))
__StringFileInfo_format__ = ( 'StringFileInfo',
('H,Length', 'H,ValueLength', 'H,Type' ))
__StringTable_format__ = ( 'StringTable',
('H,Length', 'H,ValueLength', 'H,Type' ))
__String_format__ = ( 'String',
('H,Length', 'H,ValueLength', 'H,Type' ))
__Var_format__ = ( 'Var', ('H,Length', 'H,ValueLength', 'H,Type' ))
__IMAGE_THUNK_DATA_format__ = ('IMAGE_THUNK_DATA',
('L,ForwarderString,Function,Ordinal,AddressOfData',))
__IMAGE_THUNK_DATA64_format__ = ('IMAGE_THUNK_DATA',
('Q,ForwarderString,Function,Ordinal,AddressOfData',))
__IMAGE_DEBUG_DIRECTORY_format__ = ('IMAGE_DEBUG_DIRECTORY',
('L,Characteristics', 'L,TimeDateStamp', 'H,MajorVersion',
'H,MinorVersion', 'L,Type', 'L,SizeOfData', 'L,AddressOfRawData',
'L,PointerToRawData'))
__IMAGE_BASE_RELOCATION_format__ = ('IMAGE_BASE_RELOCATION',
('L,VirtualAddress', 'L,SizeOfBlock') )
__IMAGE_TLS_DIRECTORY_format__ = ('IMAGE_TLS_DIRECTORY',
('L,StartAddressOfRawData', 'L,EndAddressOfRawData',
'L,AddressOfIndex', 'L,AddressOfCallBacks',
'L,SizeOfZeroFill', 'L,Characteristics' ) )
__IMAGE_TLS_DIRECTORY64_format__ = ('IMAGE_TLS_DIRECTORY',
('Q,StartAddressOfRawData', 'Q,EndAddressOfRawData',
'Q,AddressOfIndex', 'Q,AddressOfCallBacks',
'L,SizeOfZeroFill', 'L,Characteristics' ) )
__IMAGE_BOUND_IMPORT_DESCRIPTOR_format__ = ('IMAGE_BOUND_IMPORT_DESCRIPTOR',
('L,TimeDateStamp', 'H,OffsetModuleName', 'H,NumberOfModuleForwarderRefs'))
__IMAGE_BOUND_FORWARDER_REF_format__ = ('IMAGE_BOUND_FORWARDER_REF',
('L,TimeDateStamp', 'H,OffsetModuleName', 'H,Reserved') )
def __init__(self, name=None, data=None, fast_load=None):
self.sections = []
self.__warnings = []
self.PE_TYPE = None
if not name and not data:
return
# This list will keep track of all the structures created.
# That will allow for an easy iteration through the list
# in order to save the modifications made
self.__structures__ = []
if not fast_load:
fast_load = globals()['fast_load']
self.__parse__(name, data, fast_load)
def __unpack_data__(self, format, data, file_offset):
"""Apply structure format to raw data.
Returns and unpacked structure object if successful, None otherwise.
"""
structure = Structure(format, file_offset=file_offset)
#if len(data) < structure.sizeof():
# return None
try:
structure.__unpack__(data)
except PEFormatError, err:
self.__warnings.append(
'Corrupt header "%s" at file offset %d. Exception: %s' % (
format[0], file_offset, str(err)) )
return None
self.__structures__.append(structure)
return structure
def __parse__(self, fname, data, fast_load):
"""Parse a Portable Executable file.
Loads a PE file, parsing all its structures and making them available
through the instance's attributes.
"""
if fname:
fd = file(fname, 'rb')
self.__data__ = fd.read()
fd.close()
elif data:
self.__data__ = data
self.DOS_HEADER = self.__unpack_data__(
self.__IMAGE_DOS_HEADER_format__,
self.__data__, file_offset=0)
if not self.DOS_HEADER or self.DOS_HEADER.e_magic != IMAGE_DOS_SIGNATURE:
raise PEFormatError('DOS Header magic not found.')
# OC Patch:
# Check for sane value in e_lfanew
#
if self.DOS_HEADER.e_lfanew > len(self.__data__):
raise PEFormatError('Invalid e_lfanew value, probably not a PE file')
nt_headers_offset = self.DOS_HEADER.e_lfanew
self.NT_HEADERS = self.__unpack_data__(
self.__IMAGE_NT_HEADERS_format__,
self.__data__[nt_headers_offset:],
file_offset = nt_headers_offset)
# We better check the signature right here, before the file screws
# around with sections:
# OC Patch:
# Some malware will cause the Signature value to not exist at all
if not self.NT_HEADERS or not self.NT_HEADERS.Signature:
raise PEFormatError('NT Headers not found.')
if self.NT_HEADERS.Signature != IMAGE_NT_SIGNATURE:
raise PEFormatError('Invalid NT Headers signature.')
self.FILE_HEADER = self.__unpack_data__(
self.__IMAGE_FILE_HEADER_format__,
self.__data__[nt_headers_offset+4:],
file_offset = nt_headers_offset+4)
image_flags = self.retrieve_flags(IMAGE_CHARACTERISTICS, 'IMAGE_FILE_')
if not self.FILE_HEADER:
raise PEFormatError('File Header missing')
# Set the image's flags according the the Characteristics member
self.set_flags(self.FILE_HEADER, self.FILE_HEADER.Characteristics, image_flags)
optional_header_offset = \
nt_headers_offset+4+self.FILE_HEADER.sizeof()
# Note: location of sections can be controlled from PE header:
sections_offset = optional_header_offset + self.FILE_HEADER.SizeOfOptionalHeader
self.OPTIONAL_HEADER = self.__unpack_data__(
self.__IMAGE_OPTIONAL_HEADER_format__,
self.__data__[optional_header_offset:],
file_offset = optional_header_offset)
# According to solardesigner's findings for his
# Tiny PE project, the optional header does not
# need fields beyond "Subsystem" in order to be
# loadable by the Windows loader (given that zeroes
# are acceptable values and the header is loaded
# in a zeroed memory page)
# If trying to parse a full Optional Header fails
# we try to parse it again with some 0 padding
#
MINIMUM_VALID_OPTIONAL_HEADER_RAW_SIZE = 69
if ( self.OPTIONAL_HEADER is None and
len(self.__data__[optional_header_offset:])
>= MINIMUM_VALID_OPTIONAL_HEADER_RAW_SIZE ):
# Add enough zeroes to make up for the unused fields
#
padding_length = 128
# Create padding
#
padded_data = self.__data__[optional_header_offset:] + (
'\0' * padding_length)
self.OPTIONAL_HEADER = self.__unpack_data__(
self.__IMAGE_OPTIONAL_HEADER_format__,
padded_data,
file_offset = optional_header_offset)
# Check the Magic in the OPTIONAL_HEADER and set the PE file
# type accordingly
#
if self.OPTIONAL_HEADER is not None:
if self.OPTIONAL_HEADER.Magic == OPTIONAL_HEADER_MAGIC_PE:
self.PE_TYPE = OPTIONAL_HEADER_MAGIC_PE
elif self.OPTIONAL_HEADER.Magic == OPTIONAL_HEADER_MAGIC_PE_PLUS:
self.PE_TYPE = OPTIONAL_HEADER_MAGIC_PE_PLUS
self.OPTIONAL_HEADER = self.__unpack_data__(
self.__IMAGE_OPTIONAL_HEADER64_format__,
self.__data__[optional_header_offset:],
file_offset = optional_header_offset)
# Again, as explained above, we try to parse
# a reduced form of the Optional Header which
# is still valid despite not including all
# structure members
#
MINIMUM_VALID_OPTIONAL_HEADER_RAW_SIZE = 69+4
if ( self.OPTIONAL_HEADER is None and
len(self.__data__[optional_header_offset:])
>= MINIMUM_VALID_OPTIONAL_HEADER_RAW_SIZE ):
padding_length = 128
padded_data = self.__data__[optional_header_offset:] + (
'\0' * padding_length)
self.OPTIONAL_HEADER = self.__unpack_data__(
self.__IMAGE_OPTIONAL_HEADER64_format__,
padded_data,
file_offset = optional_header_offset)
if not self.FILE_HEADER:
raise PEFormatError('File Header missing')
# OC Patch:
# Die gracefully if there is no OPTIONAL_HEADER field
# 975440f5ad5e2e4a92c4d9a5f22f75c1
if self.PE_TYPE is None or self.OPTIONAL_HEADER is None:
raise PEFormatError("No Optional Header found, invalid PE32 or PE32+ file")
dll_characteristics_flags = self.retrieve_flags(DLL_CHARACTERISTICS, 'IMAGE_DLL_CHARACTERISTICS_')
# Set the Dll Characteristics flags according the the DllCharacteristics member
self.set_flags(
self.OPTIONAL_HEADER,
self.OPTIONAL_HEADER.DllCharacteristics,
dll_characteristics_flags)
self.OPTIONAL_HEADER.DATA_DIRECTORY = []
#offset = (optional_header_offset + self.FILE_HEADER.SizeOfOptionalHeader)
offset = (optional_header_offset + self.OPTIONAL_HEADER.sizeof())
self.NT_HEADERS.FILE_HEADER = self.FILE_HEADER
self.NT_HEADERS.OPTIONAL_HEADER = self.OPTIONAL_HEADER
# The NumberOfRvaAndSizes is sanitized to stay within
# reasonable limits so can be casted to an int
#
if self.OPTIONAL_HEADER.NumberOfRvaAndSizes > 0x10:
self.__warnings.append(
'Suspicious NumberOfRvaAndSizes in the Optional Header. ' +
'Normal values are never larger than 0x10, the value is: 0x%x' %
self.OPTIONAL_HEADER.NumberOfRvaAndSizes )
for i in xrange(int(0x7fffffffL & self.OPTIONAL_HEADER.NumberOfRvaAndSizes)):
if len(self.__data__[offset:]) == 0:
break
if len(self.__data__[offset:]) < 8:
data = self.__data__[offset:]+'\0'*8
else:
data = self.__data__[offset:]
dir_entry = self.__unpack_data__(
self.__IMAGE_DATA_DIRECTORY_format__,
data,
file_offset = offset)
if dir_entry is None:
break
# Would fail if missing an entry
# 1d4937b2fa4d84ad1bce0309857e70ca offending sample
try:
dir_entry.name = DIRECTORY_ENTRY[i]
except (KeyError, AttributeError):
break
offset += dir_entry.sizeof()
self.OPTIONAL_HEADER.DATA_DIRECTORY.append(dir_entry)
# If the offset goes outside the optional header,
# the loop is broken, regardless of how many directories
# NumberOfRvaAndSizes says there are
#
# We assume a normally sized optional header, hence that we do
# a sizeof() instead of reading SizeOfOptionalHeader.
# Then we add a default number of drectories times their size,
# if we go beyond that, we assume the number of directories
# is wrong and stop processing
if offset >= (optional_header_offset +
self.OPTIONAL_HEADER.sizeof() + 8*16) :
break
offset = self.parse_sections(sections_offset)
# OC Patch:
# There could be a problem if there are no raw data sections
# greater than 0
# fc91013eb72529da005110a3403541b6 example
# Should this throw an exception in the minimum header offset
# can't be found?
#
rawDataPointers = [
s.PointerToRawData for s in self.sections if s.PointerToRawData>0]
if len(rawDataPointers) > 0:
lowest_section_offset = min(rawDataPointers)
else:
lowest_section_offset = None
if not lowest_section_offset or lowest_section_offset<offset:
self.header = self.__data__[:offset]
else:
self.header = self.__data__[:lowest_section_offset]
# Check whether the entry point lies within a section
#
if self.get_section_by_rva(self.OPTIONAL_HEADER.AddressOfEntryPoint) is not None:
# Check whether the entry point lies within the file
#
ep_offset = self.get_offset_from_rva(self.OPTIONAL_HEADER.AddressOfEntryPoint)
if ep_offset > len(self.__data__):
self.__warnings.append(
'Possibly corrupt file. AddressOfEntryPoint lies outside the file. ' +
'AddressOfEntryPoint: 0x%x' %
self.OPTIONAL_HEADER.AddressOfEntryPoint )
else:
self.__warnings.append(
'AddressOfEntryPoint lies outside the sections\' boundaries. ' +
'AddressOfEntryPoint: 0x%x' %
self.OPTIONAL_HEADER.AddressOfEntryPoint )
if not fast_load:
self.parse_data_directories()
def get_warnings(self):
"""Return the list of warnings.
Non-critical problems found when parsing the PE file are
appended to a list of warnings. This method returns the
full list.
"""
return self.__warnings
def show_warnings(self):
"""Print the list of warnings.
Non-critical problems found when parsing the PE file are
appended to a list of warnings. This method prints the
full list to standard output.
"""
for warning in self.__warnings:
print '>', warning
def full_load(self):
"""Process the data directories.
This mathod will load the data directories which might not have
been loaded if the "fast_load" option was used.
"""
self.parse_data_directories()
def write(self, filename=None):
"""Write the PE file.
This function will process all headers and components
of the PE file and include all changes made (by just
assigning to attributes in the PE objects) and write
the changes back to a file whose name is provided as
an argument. The filename is optional, if not
provided the data will be returned as a 'str' object.
"""
file_data = list(self.__data__)
for struct in self.__structures__:
struct_data = list(struct.__pack__())
offset = struct.get_file_offset()
file_data[offset:offset+len(struct_data)] = struct_data
if hasattr(self, 'VS_VERSIONINFO'):
if hasattr(self, 'FileInfo'):
for entry in self.FileInfo:
if hasattr(entry, 'StringTable'):
for st_entry in entry.StringTable:
for key, entry in st_entry.entries.items():
offsets = st_entry.entries_offsets[key]
lengths = st_entry.entries_lengths[key]
if len( entry ) > lengths[1]:
uc = zip(
list(entry[:lengths[1]]), ['\0'] * lengths[1] )
l = list()
map(l.extend, uc)
file_data[
offsets[1] : offsets[1] + lengths[1]*2 ] = l
else:
uc = zip(
list(entry), ['\0'] * len(entry) )
l = list()
map(l.extend, uc)
file_data[
offsets[1] : offsets[1] + len(entry)*2 ] = l
remainder = lengths[1] - len(entry)
file_data[
offsets[1] + len(entry)*2 :
offsets[1] + lengths[1]*2 ] = [
u'\0' ] * remainder*2
new_file_data = ''.join( [ chr(ord(c)) for c in file_data ] )
if filename:
f = file(filename, 'wb+')
f.write(new_file_data)
f.close()
else:
return new_file_data
def parse_sections(self, offset):
"""Fetch the PE file sections.
The sections will be readily available in the "sections" attribute.
Its attributes will contain all the section information plus "data"
a buffer containing the section's data.
The "Characteristics" member will be processed and attributes
representing the section characteristics (with the 'IMAGE_SCN_'
string trimmed from the constant's names) will be added to the
section instance.
Refer to the SectionStructure class for additional info.
"""
self.sections = []
for i in xrange(self.FILE_HEADER.NumberOfSections):
section = SectionStructure(self.__IMAGE_SECTION_HEADER_format__)
if not section:
break
section_offset = offset + section.sizeof() * i
section.set_file_offset(section_offset)
section.__unpack__(self.__data__[section_offset:])
self.__structures__.append(section)
if section.SizeOfRawData > len(self.__data__):
self.__warnings.append(
('Error parsing section %d. ' % i) +
'SizeOfRawData is larger than file.')
if section.PointerToRawData > len(self.__data__):
self.__warnings.append(
('Error parsing section %d. ' % i) +
'PointerToRawData points beyond the end of the file.')
if section.Misc_VirtualSize > 0x10000000:
self.__warnings.append(
('Suspicious value found parsing section %d. ' % i) +
'VirtualSize is extremely large > 256MiB.')
if section.VirtualAddress > 0x10000000:
self.__warnings.append(
('Suspicious value found parsing section %d. ' % i) +
'VirtualAddress is beyond 0x10000000.')
#
# Some packer used a non-aligned PointerToRawData in the sections,
# which causes several common tools not to load the section data
# properly as they blindly read from the indicated offset.
# It seems that Windows will round the offset down to the largest
# offset multiple of FileAlignment which is smaller than
# PointerToRawData. The following code will do the same.
#
#alignment = self.OPTIONAL_HEADER.FileAlignment
self.update_section_data(section)
if ( self.OPTIONAL_HEADER.FileAlignment != 0 and
(section.PointerToRawData % self.OPTIONAL_HEADER.FileAlignment) != 0):
self.__warnings.append(
('Error parsing section %d. ' % i) +
'Suspicious value for FileAlignment in the Optional Header. ' +
'Normally the PointerToRawData entry of the sections\' structures ' +
'is a multiple of FileAlignment, this might imply the file ' +
'is trying to confuse tools which parse this incorrectly')
section_flags = self.retrieve_flags(SECTION_CHARACTERISTICS, 'IMAGE_SCN_')
# Set the section's flags according the the Characteristics member
self.set_flags(section, section.Characteristics, section_flags)
if ( section.__dict__.get('IMAGE_SCN_MEM_WRITE', False) and
section.__dict__.get('IMAGE_SCN_MEM_EXECUTE', False) ):
self.__warnings.append(
('Suspicious flags set for section %d. ' % i) +
'Both IMAGE_SCN_MEM_WRITE and IMAGE_SCN_MEM_EXECUTE are set.' +
'This might indicate a packed executable.')
self.sections.append(section)
if self.FILE_HEADER.NumberOfSections > 0 and self.sections:
return offset + self.sections[0].sizeof()*self.FILE_HEADER.NumberOfSections
else:
return offset
def retrieve_flags(self, flag_dict, flag_filter):
"""Read the flags from a dictionary and return them in a usable form.
Will return a list of (flag, value) for all flags in "flag_dict"
matching the filter "flag_filter".
"""
return [(f[0], f[1]) for f in flag_dict.items() if
isinstance(f[0], str) and f[0].startswith(flag_filter)]
def set_flags(self, obj, flag_field, flags):
"""Will process the flags and set attributes in the object accordingly.
The object "obj" will gain attritutes named after the flags provided in
"flags" and valued True/False, matching the results of applyin each
flag value from "flags" to flag_field.
"""
for flag in flags:
if flag[1] & flag_field:
setattr(obj, flag[0], True)
else:
setattr(obj, flag[0], False)
def parse_data_directories(self, directories=None):
"""Parse and process the PE file's data directories.
If the optional argument 'directories' is given, only
the directories at the specified indices will be parsed.
Such funcionality allows parsing of areas of interest
without the burden of having to parse all others.
The directories can then be specified as:
For export/import only:
directories = [ 0, 1 ]
or (more verbosely):
directories = [ DIRECTORY_ENTRY['IMAGE_DIRECTORY_ENTRY_IMPORT'],
DIRECTORY_ENTRY['IMAGE_DIRECTORY_ENTRY_EXPORT'] ]
If 'directories' is a list, the ones that are processed will be removed,
leaving only the ones that are not present in the image.
"""
directory_parsing = (
('IMAGE_DIRECTORY_ENTRY_IMPORT', self.parse_import_directory),
('IMAGE_DIRECTORY_ENTRY_EXPORT', self.parse_export_directory),
('IMAGE_DIRECTORY_ENTRY_RESOURCE', self.parse_resources_directory),
('IMAGE_DIRECTORY_ENTRY_DEBUG', self.parse_debug_directory),
('IMAGE_DIRECTORY_ENTRY_BASERELOC', self.parse_relocations_directory),
('IMAGE_DIRECTORY_ENTRY_TLS', self.parse_directory_tls),
('IMAGE_DIRECTORY_ENTRY_DELAY_IMPORT', self.parse_delay_import_directory),
('IMAGE_DIRECTORY_ENTRY_BOUND_IMPORT', self.parse_directory_bound_imports) )
if directories is not None:
if not isinstance(directories, (tuple, list)):
directories = [directories]
for entry in directory_parsing:
# OC Patch:
#
try:
directory_index = DIRECTORY_ENTRY[entry[0]]
dir_entry = self.OPTIONAL_HEADER.DATA_DIRECTORY[directory_index]
except IndexError:
break
# Only process all the directories if no individual ones have
# been chosen
#
if directories is None or directory_index in directories:
if dir_entry.VirtualAddress:
value = entry[1](dir_entry.VirtualAddress, dir_entry.Size)
if value:
setattr(self, entry[0][6:], value)
if (directories is not None) and isinstance(directories, list) and (entry[0] in directories):
directories.remove(directory_index)
def parse_directory_bound_imports(self, rva, size):
""""""
bnd_descr = Structure(self.__IMAGE_BOUND_IMPORT_DESCRIPTOR_format__)
bnd_descr_size = bnd_descr.sizeof()
start = rva
bound_imports = []
while True:
bnd_descr = self.__unpack_data__(
self.__IMAGE_BOUND_IMPORT_DESCRIPTOR_format__,
self.__data__[rva:rva+bnd_descr_size],
file_offset = rva)
if bnd_descr is None:
# If can't parse directory then silently return.
# This directory does not necesarily have to be valid to
# still have a valid PE file
self.__warnings.append(
'The Bound Imports directory exists but can\'t be parsed.')
return
if bnd_descr.all_zeroes():
break
rva += bnd_descr.sizeof()
forwarder_refs = []
for idx in xrange(bnd_descr.NumberOfModuleForwarderRefs):
# Both structures IMAGE_BOUND_IMPORT_DESCRIPTOR and
# IMAGE_BOUND_FORWARDER_REF have the same size.
bnd_frwd_ref = self.__unpack_data__(
self.__IMAGE_BOUND_FORWARDER_REF_format__,
self.__data__[rva:rva+bnd_descr_size],
file_offset = rva)
# OC Patch:
if not bnd_frwd_ref:
raise PEFormatError(
"IMAGE_BOUND_FORWARDER_REF cannot be read")
rva += bnd_frwd_ref.sizeof()
name_str = self.get_string_from_data(
start+bnd_frwd_ref.OffsetModuleName, self.__data__)
if not name_str:
break
forwarder_refs.append(BoundImportRefData(
struct = bnd_frwd_ref,
name = name_str))
name_str = self.get_string_from_data(
start+bnd_descr.OffsetModuleName, self.__data__)
if not name_str:
break
bound_imports.append(
BoundImportDescData(
struct = bnd_descr,
name = name_str,
entries = forwarder_refs))
return bound_imports
def parse_directory_tls(self, rva, size):
""""""
if self.PE_TYPE == OPTIONAL_HEADER_MAGIC_PE:
format = self.__IMAGE_TLS_DIRECTORY_format__
elif self.PE_TYPE == OPTIONAL_HEADER_MAGIC_PE_PLUS:
format = self.__IMAGE_TLS_DIRECTORY64_format__
tls_struct = self.__unpack_data__(
format,
self.get_data( rva, Structure(format).sizeof() ),
file_offset = self.get_offset_from_rva(rva))
if not tls_struct:
return None
return TlsData( struct = tls_struct )
def parse_relocations_directory(self, rva, size):
""""""
rlc_size = Structure(self.__IMAGE_BASE_RELOCATION_format__).sizeof()
end = rva+size
relocations = []
while rva<end:
# OC Patch:
# Malware that has bad rva entries will cause an error.
# Just continue on after an exception
#
try:
rlc = self.__unpack_data__(
self.__IMAGE_BASE_RELOCATION_format__,
self.get_data(rva, rlc_size),
file_offset = self.get_offset_from_rva(rva) )
except PEFormatError:
self.__warnings.append(
'Invalid relocation information. Can\'t read ' +
'data at RVA: 0x%x' % rva)
rlc = None
if not rlc:
break
reloc_entries = self.parse_relocations(
rva+rlc_size, rlc.VirtualAddress, rlc.SizeOfBlock-rlc_size)
relocations.append(
BaseRelocationData(
struct = rlc,
entries = reloc_entries))
if not rlc.SizeOfBlock:
break
rva += rlc.SizeOfBlock
return relocations
def parse_relocations(self, data_rva, rva, size):
""""""
data = self.get_data(data_rva, size)
entries = []
for idx in xrange(len(data)/2):
word = struct.unpack('<H', data[idx*2:(idx+1)*2])[0]
reloc_type = (word>>12)
reloc_offset = (word&0x0fff)
entries.append(
RelocationData(
type = reloc_type,
rva = reloc_offset+rva))
return entries
def parse_debug_directory(self, rva, size):
""""""
dbg_size = Structure(self.__IMAGE_DEBUG_DIRECTORY_format__).sizeof()
debug = []
for idx in xrange(size/dbg_size):
try:
data = self.get_data(rva+dbg_size*idx, dbg_size)
except PEFormatError, e:
self.__warnings.append(
'Invalid debug information. Can\'t read ' +
'data at RVA: 0x%x' % rva)
return None
dbg = self.__unpack_data__(
self.__IMAGE_DEBUG_DIRECTORY_format__,
data, file_offset = self.get_offset_from_rva(rva+dbg_size*idx))
if not dbg:
return None
debug.append(
DebugData(
struct = dbg))
return debug
def parse_resources_directory(self, rva, size=0, base_rva = None, level = 0):
"""Parse the resources directory.
Given the rva of the resources directory, it will process all
its entries.
The root will have the corresponding member of its structure,
IMAGE_RESOURCE_DIRECTORY plus 'entries', a list of all the
entries in the directory.
Those entries will have, correspondingly, all the structure's
members (IMAGE_RESOURCE_DIRECTORY_ENTRY) and an additional one,
"directory", pointing to the IMAGE_RESOURCE_DIRECTORY structure
representing upper layers of the tree. This one will also have
an 'entries' attribute, pointing to the 3rd, and last, level.
Another directory with more entries. Those last entries will
have a new atribute (both 'leaf' or 'data_entry' can be used to
access it). This structure finally points to the resource data.
All the members of this structure, IMAGE_RESOURCE_DATA_ENTRY,
are available as its attributes.
"""
# OC Patch:
original_rva = rva
if base_rva is None:
base_rva = rva
resources_section = self.get_section_by_rva(rva)
try:
# If the RVA is invalid all would blow up. Some EXEs seem to be
# specially nasty and have an invalid RVA.
data = self.get_data(rva, Structure(self.__IMAGE_RESOURCE_DIRECTORY_format__).sizeof() )
except PEFormatError, e:
self.__warnings.append(
'Invalid resources directory. Can\'t read ' +
'directory data at RVA: 0x%x' % rva)
return None
# Get the resource directory structure, that is, the header
# of the table preceding the actual entries
#
resource_dir = self.__unpack_data__(
self.__IMAGE_RESOURCE_DIRECTORY_format__, data,
file_offset = self.get_offset_from_rva(rva) )
if resource_dir is None:
# If can't parse resources directory then silently return.
# This directory does not necesarily have to be valid to
# still have a valid PE file
self.__warnings.append(
'Invalid resources directory. Can\'t parse ' +
'directory data at RVA: 0x%x' % rva)
return None
dir_entries = []
# Advance the rva to the positon immediately following the directory
# table header and pointing to the first entry in the table
#
rva += resource_dir.sizeof()
number_of_entries = (
resource_dir.NumberOfNamedEntries +
resource_dir.NumberOfIdEntries )
strings_to_postprocess = list()
for idx in xrange(number_of_entries):
res = self.parse_resource_entry(rva)
if res is None:
self.__warnings.append(
'Error parsing the resources directory, ' +
'Entry %d is invalid, RVA = 0x%x. ' %
(idx, rva) )
break
entry_name = None
entry_id = None
# If all named entries have been processed, only Id ones
# remain
if idx >= resource_dir.NumberOfNamedEntries:
entry_id = res.Name
else:
ustr_offset = base_rva+res.NameOffset
try:
#entry_name = self.get_string_u_at_rva(ustr_offset, max_length=16)
entry_name = UnicodeStringWrapperPostProcessor(self, ustr_offset)
strings_to_postprocess.append(entry_name)
except PEFormatError, excp:
self.__warnings.append(
'Error parsing the resources directory, ' +
'attempting to read entry name. ' +
'Can\'t read unicode string at offset 0x%x' %
(ustr_offset) )
if res.DataIsDirectory:
# OC Patch:
#
# One trick malware can do is to recursively reference
# the next directory. This causes hilarity to ensue when
# trying to parse everything correctly.
# If the original RVA given to this function is equal to
# the next one to parse, we assume that it's a trick.
# Instead of raising a PEFormatError this would skip some
# reasonable data so we just break.
#
# 9ee4d0a0caf095314fd7041a3e4404dc is the offending sample
if original_rva == (base_rva + res.OffsetToDirectory):
break
else:
entry_directory = self.parse_resources_directory(
base_rva+res.OffsetToDirectory,
base_rva=base_rva, level = level+1)
if not entry_directory:
break
dir_entries.append(
ResourceDirEntryData(
struct = res,
name = entry_name,
id = entry_id,
directory = entry_directory))
else:
struct = self.parse_resource_data_entry(
base_rva + res.OffsetToDirectory)
if struct:
entry_data = ResourceDataEntryData(
struct = struct,
lang = res.Name & 0xff,
sublang = (res.Name>>8) & 0xff)
dir_entries.append(
ResourceDirEntryData(
struct = res,
name = entry_name,
id = entry_id,
data = entry_data))
else:
break
# Check if this entry contains version information
#
if level == 0 and res.Id == RESOURCE_TYPE['RT_VERSION']:
if len(dir_entries)>0:
last_entry = dir_entries[-1]
rt_version_struct = None
try:
rt_version_struct = last_entry.directory.entries[0].directory.entries[0].data.struct
except:
# Maybe a malformed directory structure...?
# Lets ignore it
pass
if rt_version_struct is not None:
self.parse_version_information(rt_version_struct)
rva += res.sizeof()
string_rvas = [s.get_rva() for s in strings_to_postprocess]
string_rvas.sort()
for idx, s in enumerate(strings_to_postprocess):
s.render_pascal_16()
resource_directory_data = ResourceDirData(
struct = resource_dir,
entries = dir_entries)
return resource_directory_data
def parse_resource_data_entry(self, rva):
"""Parse a data entry from the resources directory."""
try:
# If the RVA is invalid all would blow up. Some EXEs seem to be
# specially nasty and have an invalid RVA.
data = self.get_data(rva, Structure(self.__IMAGE_RESOURCE_DATA_ENTRY_format__).sizeof() )
except PEFormatError, excp:
self.__warnings.append(
'Error parsing a resource directory data entry, ' +
'the RVA is invalid: 0x%x' % ( rva ) )
return None
data_entry = self.__unpack_data__(
self.__IMAGE_RESOURCE_DATA_ENTRY_format__, data,
file_offset = self.get_offset_from_rva(rva) )
return data_entry
def parse_resource_entry(self, rva):
"""Parse a directory entry from the resources directory."""
resource = self.__unpack_data__(
self.__IMAGE_RESOURCE_DIRECTORY_ENTRY_format__,
self.get_data( rva, Structure(self.__IMAGE_RESOURCE_DIRECTORY_ENTRY_format__).sizeof() ),
file_offset = self.get_offset_from_rva(rva) )
if resource is None:
return None
#resource.NameIsString = (resource.Name & 0x80000000L) >> 31
resource.NameOffset = resource.Name & 0x7FFFFFFFL
resource.__pad = resource.Name & 0xFFFF0000L
resource.Id = resource.Name & 0x0000FFFFL
resource.DataIsDirectory = (resource.OffsetToData & 0x80000000L) >> 31
resource.OffsetToDirectory = resource.OffsetToData & 0x7FFFFFFFL
return resource
def parse_version_information(self, version_struct):
"""Parse version information structure.
The date will be made available in three attributes of the PE object.
VS_VERSIONINFO will contain the first three fields of the main structure:
'Length', 'ValueLength', and 'Type'
VS_FIXEDFILEINFO will hold the rest of the fields, accessible as sub-attributes:
'Signature', 'StrucVersion', 'FileVersionMS', 'FileVersionLS',
'ProductVersionMS', 'ProductVersionLS', 'FileFlagsMask', 'FileFlags',
'FileOS', 'FileType', 'FileSubtype', 'FileDateMS', 'FileDateLS'
FileInfo is a list of all StringFileInfo and VarFileInfo structures.
StringFileInfo structures will have a list as an attribute named 'StringTable'
containing all the StringTable structures. Each of those structures contains a
dictionary 'entries' with all the key/value version information string pairs.
VarFileInfo structures will have a list as an attribute named 'Var' containing
all Var structures. Each Var structure will have a dictionary as an attribute
named 'entry' which will contain the name and value of the Var.
"""
# Retrieve the data for the version info resource
#
start_offset = self.get_offset_from_rva( version_struct.OffsetToData )
raw_data = self.__data__[ start_offset : start_offset+version_struct.Size ]
# Map the main structure and the subsequent string
#
versioninfo_struct = self.__unpack_data__(
self.__VS_VERSIONINFO_format__, raw_data,
file_offset = start_offset )
if versioninfo_struct is None:
return
ustr_offset = version_struct.OffsetToData + versioninfo_struct.sizeof()
try:
versioninfo_string = self.get_string_u_at_rva( ustr_offset )
except PEFormatError, excp:
self.__warnings.append(
'Error parsing the version information, ' +
'attempting to read VS_VERSION_INFO string. Can\'t ' +
'read unicode string at offset 0x%x' % (
ustr_offset ) )
versioninfo_string = None
# If the structure does not contain the expected name, it's assumed to be invalid
#
if versioninfo_string != u'VS_VERSION_INFO':
self.__warnings.append('Invalid VS_VERSION_INFO block')
return
# Set the PE object's VS_VERSIONINFO to this one
#
self.VS_VERSIONINFO = versioninfo_struct
# The the Key attribute to point to the unicode string identifying the structure
#
self.VS_VERSIONINFO.Key = versioninfo_string
# Process the fixed version information, get the offset and structure
#
fixedfileinfo_offset = self.dword_align(
versioninfo_struct.sizeof() + 2 * (len(versioninfo_string) + 1),
version_struct.OffsetToData)
fixedfileinfo_struct = self.__unpack_data__(
self.__VS_FIXEDFILEINFO_format__,
raw_data[fixedfileinfo_offset:],
file_offset = start_offset+fixedfileinfo_offset )
if not fixedfileinfo_struct:
return
# Set the PE object's VS_FIXEDFILEINFO to this one
#
self.VS_FIXEDFILEINFO = fixedfileinfo_struct
# Start parsing all the StringFileInfo and VarFileInfo structures
#
# Get the first one
#
stringfileinfo_offset = self.dword_align(
fixedfileinfo_offset + fixedfileinfo_struct.sizeof(),
version_struct.OffsetToData)
original_stringfileinfo_offset = stringfileinfo_offset
# Set the PE object's attribute that will contain them all.
#
self.FileInfo = list()
while True:
# Process the StringFileInfo/VarFileInfo struct
#
stringfileinfo_struct = self.__unpack_data__(
self.__StringFileInfo_format__,
raw_data[stringfileinfo_offset:],
file_offset = start_offset+stringfileinfo_offset )
if stringfileinfo_struct is None:
self.__warnings.append(
'Error parsing StringFileInfo/VarFileInfo struct' )
return None
# Get the subsequent string defining the structure.
#
ustr_offset = ( version_struct.OffsetToData +
stringfileinfo_offset + versioninfo_struct.sizeof() )
try:
stringfileinfo_string = self.get_string_u_at_rva( ustr_offset )
except PEFormatError, excp:
self.__warnings.append(
'Error parsing the version information, ' +
'attempting to read StringFileInfo string. Can\'t ' +
'read unicode string at offset 0x%x' % ( ustr_offset ) )
break
# Set such string as the Key attribute
#
stringfileinfo_struct.Key = stringfileinfo_string
# Append the structure to the PE object's list
#
self.FileInfo.append(stringfileinfo_struct)
# Parse a StringFileInfo entry
#
if stringfileinfo_string.startswith(u'StringFileInfo'):
if stringfileinfo_struct.Type == 1 and stringfileinfo_struct.ValueLength == 0:
stringtable_offset = self.dword_align(
stringfileinfo_offset + stringfileinfo_struct.sizeof() +
2*(len(stringfileinfo_string)+1),
version_struct.OffsetToData)
stringfileinfo_struct.StringTable = list()
# Process the String Table entries
#
while True:
stringtable_struct = self.__unpack_data__(
self.__StringTable_format__,
raw_data[stringtable_offset:],
file_offset = start_offset+stringtable_offset )
if not stringtable_struct:
break
ustr_offset = ( version_struct.OffsetToData + stringtable_offset +
stringtable_struct.sizeof() )
try:
stringtable_string = self.get_string_u_at_rva( ustr_offset )
except PEFormatError, excp:
self.__warnings.append(
'Error parsing the version information, ' +
'attempting to read StringTable string. Can\'t ' +
'read unicode string at offset 0x%x' % ( ustr_offset ) )
break
stringtable_struct.LangID = stringtable_string
stringtable_struct.entries = dict()
stringtable_struct.entries_offsets = dict()
stringtable_struct.entries_lengths = dict()
stringfileinfo_struct.StringTable.append(stringtable_struct)
entry_offset = self.dword_align(
stringtable_offset + stringtable_struct.sizeof() +
2*(len(stringtable_string)+1),
version_struct.OffsetToData)
# Process all entries in the string table
#
while entry_offset < stringtable_offset + stringtable_struct.Length:
string_struct = self.__unpack_data__(
self.__String_format__, raw_data[entry_offset:],
file_offset = start_offset+entry_offset )
if not string_struct:
break
ustr_offset = ( version_struct.OffsetToData + entry_offset +
string_struct.sizeof() )
try:
key = self.get_string_u_at_rva( ustr_offset )
key_offset = self.get_offset_from_rva( ustr_offset )
except PEFormatError, excp:
self.__warnings.append(
'Error parsing the version information, ' +
'attempting to read StringTable Key string. Can\'t ' +
'read unicode string at offset 0x%x' % ( ustr_offset ) )
break
value_offset = self.dword_align(
2*(len(key)+1) + entry_offset + string_struct.sizeof(),
version_struct.OffsetToData)
ustr_offset = version_struct.OffsetToData + value_offset
try:
value = self.get_string_u_at_rva( ustr_offset,
max_length = string_struct.ValueLength )
value_offset = self.get_offset_from_rva( ustr_offset )
except PEFormatError, excp:
self.__warnings.append(
'Error parsing the version information, ' +
'attempting to read StringTable Value string. ' +
'Can\'t read unicode string at offset 0x%x' % (
ustr_offset ) )
break
if string_struct.Length == 0:
entry_offset = stringtable_offset + stringtable_struct.Length
else:
entry_offset = self.dword_align(
string_struct.Length+entry_offset, version_struct.OffsetToData)
key_as_char = []
for c in key:
if ord(c)>128:
key_as_char.append('\\x%02x' %ord(c))
else:
key_as_char.append(c)
key_as_char = ''.join(key_as_char)
setattr(stringtable_struct, key_as_char, value)
stringtable_struct.entries[key] = value
stringtable_struct.entries_offsets[key] = (key_offset, value_offset)
stringtable_struct.entries_lengths[key] = (len(key), len(value))
stringtable_offset = self.dword_align(
stringtable_struct.Length + stringtable_offset,
version_struct.OffsetToData)
if stringtable_offset >= stringfileinfo_struct.Length:
break
# Parse a VarFileInfo entry
#
elif stringfileinfo_string.startswith( u'VarFileInfo' ):
varfileinfo_struct = stringfileinfo_struct
varfileinfo_struct.name = 'VarFileInfo'
if varfileinfo_struct.Type == 1 and varfileinfo_struct.ValueLength == 0:
var_offset = self.dword_align(
stringfileinfo_offset + varfileinfo_struct.sizeof() +
2*(len(stringfileinfo_string)+1),
version_struct.OffsetToData)
varfileinfo_struct.Var = list()
# Process all entries
#
while True:
var_struct = self.__unpack_data__(
self.__Var_format__,
raw_data[var_offset:],
file_offset = start_offset+var_offset )
if not var_struct:
break
ustr_offset = ( version_struct.OffsetToData + var_offset +
var_struct.sizeof() )
try:
var_string = self.get_string_u_at_rva( ustr_offset )
except PEFormatError, excp:
self.__warnings.append(
'Error parsing the version information, ' +
'attempting to read VarFileInfo Var string. ' +
'Can\'t read unicode string at offset 0x%x' % (ustr_offset))
break
varfileinfo_struct.Var.append(var_struct)
varword_offset = self.dword_align(
2*(len(var_string)+1) + var_offset + var_struct.sizeof(),
version_struct.OffsetToData)
orig_varword_offset = varword_offset
while varword_offset < orig_varword_offset + var_struct.ValueLength:
word1 = self.get_word_from_data(
raw_data[varword_offset:varword_offset+2], 0)
word2 = self.get_word_from_data(
raw_data[varword_offset+2:varword_offset+4], 0)
varword_offset += 4
if isinstance(word1, (int, long)) and isinstance(word1, (int, long)):
var_struct.entry = {var_string: '0x%04x 0x%04x' % (word1, word2)}
var_offset = self.dword_align(
var_offset+var_struct.Length, version_struct.OffsetToData)
if var_offset <= var_offset+var_struct.Length:
break
# Increment and align the offset
#
stringfileinfo_offset = self.dword_align(
stringfileinfo_struct.Length+stringfileinfo_offset,
version_struct.OffsetToData)
# Check if all the StringFileInfo and VarFileInfo items have been processed
#
if stringfileinfo_struct.Length == 0 or stringfileinfo_offset >= versioninfo_struct.Length:
break
def parse_export_directory(self, rva, size):
"""Parse the export directory.
Given the rva of the export directory, it will process all
its entries.
The exports will be made available through a list "exports"
containing a tuple with the following elements:
(ordinal, symbol_address, symbol_name)
And also through a dicionary "exports_by_ordinal" whose keys
will be the ordinals and the values tuples of the from:
(symbol_address, symbol_name)
The symbol addresses are relative, not absolute.
"""
try:
export_dir = self.__unpack_data__(
self.__IMAGE_EXPORT_DIRECTORY_format__,
self.get_data( rva, Structure(self.__IMAGE_EXPORT_DIRECTORY_format__).sizeof() ),
file_offset = self.get_offset_from_rva(rva) )
except PEFormatError:
self.__warnings.append(
'Error parsing export directory at RVA: 0x%x' % ( rva ) )
return
if not export_dir:
return
try:
address_of_names = self.get_data(
export_dir.AddressOfNames, export_dir.NumberOfNames*4)
address_of_name_ordinals = self.get_data(
export_dir.AddressOfNameOrdinals, export_dir.NumberOfNames*4)
address_of_functions = self.get_data(
export_dir.AddressOfFunctions, export_dir.NumberOfFunctions*4)
except PEFormatError:
self.__warnings.append(
'Error parsing export directory at RVA: 0x%x' % ( rva ) )
return
exports = []
for i in xrange(export_dir.NumberOfNames):
symbol_name = self.get_string_at_rva(
self.get_dword_from_data(address_of_names, i))
symbol_ordinal = self.get_word_from_data(
address_of_name_ordinals, i)
if symbol_ordinal*4<len(address_of_functions):
symbol_address = self.get_dword_from_data(
address_of_functions, symbol_ordinal)
else:
# Corrupt? a bad pointer... we assume it's all
# useless, no exports
return None
# If the funcion's rva points within the export directory
# it will point to a string with the forwarded symbol's string
# instead of pointing the the function start address.
if symbol_address>=rva and symbol_address<rva+size:
forwarder_str = self.get_string_at_rva(symbol_address)
else:
forwarder_str = None
exports.append(
ExportData(
ordinal = export_dir.Base+symbol_ordinal,
address = symbol_address,
name = symbol_name,
forwarder = forwarder_str))
ordinals = [exp.ordinal for exp in exports]
for idx in xrange(export_dir.NumberOfFunctions):
if not idx+export_dir.Base in ordinals:
symbol_address = self.get_dword_from_data(
address_of_functions,
idx)
#
# Checking for forwarder again.
#
if symbol_address>=rva and symbol_address<rva+size:
forwarder_str = self.get_string_at_rva(symbol_address)
else:
forwarder_str = None
exports.append(
ExportData(
ordinal = export_dir.Base+idx,
address = symbol_address,
name = None,
forwarder = forwarder_str))
return ExportDirData(
struct = export_dir,
symbols = exports)
def dword_align(self, offset, base):
offset += base
return (offset+3) - ((offset+3)%4) - base
def parse_delay_import_directory(self, rva, size):
"""Walk and parse the delay import directory."""
import_descs = []
while True:
try:
# If the RVA is invalid all would blow up. Some PEs seem to be
# specially nasty and have an invalid RVA.
data = self.get_data( rva, Structure(self.__IMAGE_DELAY_IMPORT_DESCRIPTOR_format__).sizeof() )
except PEFormatError, e:
self.__warnings.append(
'Error parsing the Delay import directory at RVA: 0x%x' % ( rva ) )
break
import_desc = self.__unpack_data__(
self.__IMAGE_DELAY_IMPORT_DESCRIPTOR_format__,
data, file_offset = self.get_offset_from_rva(rva) )
# If the structure is all zeores, we reached the end of the list
if not import_desc or import_desc.all_zeroes():
break
rva += import_desc.sizeof()
try:
import_data = self.parse_imports(
import_desc.pINT,
import_desc.pIAT,
None)
except PEFormatError, e:
self.__warnings.append(
'Error parsing the Delay import directory. ' +
'Invalid import data at RVA: 0x%x' % ( rva ) )
break
if not import_data:
continue
dll = self.get_string_at_rva(import_desc.szName)
if dll:
import_descs.append(
ImportDescData(
struct = import_desc,
imports = import_data,
dll = dll))
return import_descs
def parse_import_directory(self, rva, size):
"""Walk and parse the import directory."""
import_descs = []
while True:
try:
# If the RVA is invalid all would blow up. Some EXEs seem to be
# specially nasty and have an invalid RVA.
data = self.get_data(rva, Structure(self.__IMAGE_IMPORT_DESCRIPTOR_format__).sizeof() )
except PEFormatError, e:
self.__warnings.append(
'Error parsing the Import directory at RVA: 0x%x' % ( rva ) )
break
import_desc = self.__unpack_data__(
self.__IMAGE_IMPORT_DESCRIPTOR_format__,
data, file_offset = self.get_offset_from_rva(rva) )
# If the structure is all zeores, we reached the end of the list
if not import_desc or import_desc.all_zeroes():
break
rva += import_desc.sizeof()
try:
import_data = self.parse_imports(
import_desc.OriginalFirstThunk,
import_desc.FirstThunk,
import_desc.ForwarderChain)
except PEFormatError, excp:
self.__warnings.append(
'Error parsing the Import directory. ' +
'Invalid Import data at RVA: 0x%x' % ( rva ) )
break
#raise excp
if not import_data:
continue
dll = self.get_string_at_rva(import_desc.Name)
if dll:
import_descs.append(
ImportDescData(
struct = import_desc,
imports = import_data,
dll = dll))
return import_descs
def parse_imports(self, original_first_thunk, first_thunk, forwarder_chain):
"""Parse the imported symbols.
It will fill a list, which will be avalable as the dictionary
attribute "imports". Its keys will be the DLL names and the values
all the symbols imported from that object.
"""
imported_symbols = []
imports_section = self.get_section_by_rva(first_thunk)
if not imports_section:
raise PEFormatError, 'Invalid/corrupt imports.'
# Import Lookup Table. Contains ordinals or pointers to strings.
ilt = self.get_import_table(original_first_thunk)
# Import Address Table. May have identical content to ILT if
# PE file is not bounded, Will contain the address of the
# imported symbols once the binary is loaded or if it is already
# bound.
iat = self.get_import_table(first_thunk)
# OC Patch:
# Would crash if iat or ilt had None type
if not iat and not ilt:
raise PEFormatError(
'Invalid Import Table information. ' +
'Both ILT and IAT appear to be broken.')
table = None
if ilt:
table = ilt
elif iat:
table = iat
else:
return None
for idx in xrange(len(table)):
imp_ord = None
imp_hint = None
imp_name = None
hint_name_table_rva = None
if table[idx].AddressOfData:
if self.PE_TYPE == OPTIONAL_HEADER_MAGIC_PE:
ordinal_flag = IMAGE_ORDINAL_FLAG
elif self.PE_TYPE == OPTIONAL_HEADER_MAGIC_PE_PLUS:
ordinal_flag = IMAGE_ORDINAL_FLAG64
# If imported by ordinal, we will append the ordinal number
#
if table[idx].AddressOfData & ordinal_flag:
import_by_ordinal = True
imp_ord = table[idx].AddressOfData & 0xffff
imp_name = None
else:
import_by_ordinal = False
try:
hint_name_table_rva = table[idx].AddressOfData & 0x7fffffff
data = self.get_data(hint_name_table_rva, 2)
# Get the Hint
imp_hint = self.get_word_from_data(data, 0)
imp_name = self.get_string_at_rva(table[idx].AddressOfData+2)
except PEFormatError, e:
pass
imp_address = first_thunk+self.OPTIONAL_HEADER.ImageBase+idx*4
if iat and ilt and ilt[idx].AddressOfData != iat[idx].AddressOfData:
imp_bound = iat[idx].AddressOfData
else:
imp_bound = None
if imp_name != '' and (imp_ord or imp_name):
imported_symbols.append(
ImportData(
import_by_ordinal = import_by_ordinal,
ordinal = imp_ord,
hint = imp_hint,
name = imp_name,
bound = imp_bound,
address = imp_address,
hint_name_table_rva = hint_name_table_rva))
return imported_symbols
def get_import_table(self, rva):
table = []
while True and rva:
if self.PE_TYPE == OPTIONAL_HEADER_MAGIC_PE:
format = self.__IMAGE_THUNK_DATA_format__
elif self.PE_TYPE == OPTIONAL_HEADER_MAGIC_PE_PLUS:
format = self.__IMAGE_THUNK_DATA64_format__
try:
data = self.get_data( rva, Structure(format).sizeof() )
except PEFormatError, e:
self.__warnings.append(
'Error parsing the import table. ' +
'Invalid data at RVA: 0x%x' % ( rva ) )
return None
thunk_data = self.__unpack_data__(
format, data, file_offset=self.get_offset_from_rva(rva) )
if not thunk_data or thunk_data.all_zeroes():
break
rva += thunk_data.sizeof()
table.append(thunk_data)
return table
def get_memory_mapped_image(self, max_virtual_address=0x10000000, ImageBase=None):
"""Returns the data corresponding to the memory layout of the PE file.
The data includes the PE header and the sections loaded at offsets
corresponding to their relative virtual addresses. (the VirtualAddress
section header member).
Any offset in this data corresponds to the absolute memory address
ImageBase+offset.
The optional argument 'max_virtual_address' provides with means of limiting
which section are processed.
Any section with their VirtualAddress beyond this value will be skipped.
Normally, sections with values beyond this range are just there to confuse
tools. It's a common trick to see in packed executables.
If the 'ImageBase' optional argument is supplied, the file's relocations
will be applied to the image by calling the 'relocate_image()' method. Beware
that the relocation information is applied permanently.
"""
# Rebase if requested
#
if ImageBase is not None:
# Keep a copy of the image's data before modifying it by rebasing it
#
original_data = self.__data__
self.relocate_image(ImageBase)
# Collect all sections in one code block
mapped_data = self.header
for section in self.sections:
# Miscellanous integrity tests.
# Some packer will set these to bogus values to
# make tools go nuts.
#
if section.Misc_VirtualSize == 0 or section.SizeOfRawData == 0:
continue
if section.SizeOfRawData > len(self.__data__):
continue
if section.PointerToRawData > len(self.__data__):
continue
if section.VirtualAddress >= max_virtual_address:
continue
padding_length = section.VirtualAddress - len(mapped_data)
if padding_length>0:
mapped_data += '\0'*padding_length
elif padding_length<0:
mapped_data = mapped_data[:padding_length]
mapped_data += section.data
# If the image was rebased, restore it to its original form
#
if ImageBase is not None:
self.__data__ = original_data
self.update_all_section_data()
return mapped_data
def get_data(self, rva, length=None):
"""Get data regardless of the section where it lies on.
Given a rva and the size of the chunk to retrieve, this method
will find the section where the data lies and return the data.
"""
s = self.get_section_by_rva(rva)
if not s:
if rva<len(self.header):
if length:
end = rva+length
else:
end = None
return self.header[rva:end]
raise PEFormatError, 'data at RVA can\'t be fetched. Corrupt header?'
return s.get_data(rva, length)
def get_rva_from_offset(self, offset):
"""Get the rva corresponding to this file offset. """
s = self.get_section_by_offset(offset)
if not s:
raise PEFormatError("specified offset (0x%x) doesn't belong to any section." % offset)
return s.get_rva_from_offset(offset)
def get_offset_from_rva(self, rva):
"""Get the file offset corresponding to this rva.
Given a rva , this method will find the section where the
data lies and return the offset within the file.
"""
s = self.get_section_by_rva(rva)
if not s:
raise PEFormatError, 'data at RVA can\'t be fetched. Corrupt header?'
return s.get_offset_from_rva(rva)
def get_string_at_rva(self, rva):
"""Get an ASCII string located at the given address."""
s = self.get_section_by_rva(rva)
if not s:
if rva<len(self.header):
return self.get_string_from_data(rva, self.header)
return None
return self.get_string_from_data(rva-s.VirtualAddress, s.data)
def get_string_from_data(self, offset, data):
"""Get an ASCII string from within the data."""
# OC Patch
b = None
try:
b = data[offset]
except IndexError:
return ''
s = ''
while ord(b):
s += b
offset += 1
try:
b = data[offset]
except IndexError:
break
return s
def get_string_u_at_rva(self, rva, max_length = 2**16):
"""Get an Unicode string located at the given address."""
try:
# If the RVA is invalid all would blow up. Some EXEs seem to be
# specially nasty and have an invalid RVA.
data = self.get_data(rva, 2)
except PEFormatError, e:
return None
#length = struct.unpack('<H', data)[0]
s = u''
for idx in xrange(max_length):
try:
uchr = struct.unpack('<H', self.get_data(rva+2*idx, 2))[0]
except struct.error:
break
if unichr(uchr) == u'\0':
break
s += unichr(uchr)
return s
def get_section_by_offset(self, offset):
"""Get the section containing the given file offset."""
sections = [s for s in self.sections if s.contains_offset(offset)]
if sections:
return sections[0]
return None
def get_section_by_rva(self, rva):
"""Get the section containing the given address."""
sections = [s for s in self.sections if s.contains_rva(rva)]
if sections:
return sections[0]
return None
def __str__(self):
return self.dump_info()
def print_info(self):
"""Print all the PE header information in a human readable from."""
print self.dump_info()
def dump_info(self, dump=None):
"""Dump all the PE header information into human readable string."""
if dump is None:
dump = Dump()
warnings = self.get_warnings()
if warnings:
dump.add_header('Parsing Warnings')
for warning in warnings:
dump.add_line(warning)
dump.add_newline()
dump.add_header('DOS_HEADER')
dump.add_lines(self.DOS_HEADER.dump())
dump.add_newline()
dump.add_header('NT_HEADERS')
dump.add_lines(self.NT_HEADERS.dump())
dump.add_newline()
dump.add_header('FILE_HEADER')
dump.add_lines(self.FILE_HEADER.dump())
image_flags = self.retrieve_flags(IMAGE_CHARACTERISTICS, 'IMAGE_FILE_')
dump.add('Flags: ')
flags = []
for flag in image_flags:
if getattr(self.FILE_HEADER, flag[0]):
flags.append(flag[0])
dump.add_line(', '.join(flags))
dump.add_newline()
if hasattr(self, 'OPTIONAL_HEADER') and self.OPTIONAL_HEADER is not None:
dump.add_header('OPTIONAL_HEADER')
dump.add_lines(self.OPTIONAL_HEADER.dump())
dll_characteristics_flags = self.retrieve_flags(DLL_CHARACTERISTICS, 'IMAGE_DLL_CHARACTERISTICS_')
dump.add('DllCharacteristics: ')
flags = []
for flag in dll_characteristics_flags:
if getattr(self.OPTIONAL_HEADER, flag[0]):
flags.append(flag[0])
dump.add_line(', '.join(flags))
dump.add_newline()
dump.add_header('PE Sections')
section_flags = self.retrieve_flags(SECTION_CHARACTERISTICS, 'IMAGE_SCN_')
for section in self.sections:
dump.add_lines(section.dump())
dump.add('Flags: ')
flags = []
for flag in section_flags:
if getattr(section, flag[0]):
flags.append(flag[0])
dump.add_line(', '.join(flags))
dump.add_line('Entropy: %f (Min=0.0, Max=8.0)' % section.get_entropy() )
if md5 is not None:
dump.add_line('MD5 hash: %s' % section.get_hash_md5() )
if sha1 is not None:
dump.add_line('SHA-1 hash: %s' % section.get_hash_sha1() )
if sha256 is not None:
dump.add_line('SHA-256 hash: %s' % section.get_hash_sha256() )
if sha512 is not None:
dump.add_line('SHA-512 hash: %s' % section.get_hash_sha512() )
dump.add_newline()
if (hasattr(self, 'OPTIONAL_HEADER') and
hasattr(self.OPTIONAL_HEADER, 'DATA_DIRECTORY') ):
dump.add_header('Directories')
for idx in xrange(len(self.OPTIONAL_HEADER.DATA_DIRECTORY)):
directory = self.OPTIONAL_HEADER.DATA_DIRECTORY[idx]
dump.add_lines(directory.dump())
dump.add_newline()
def convert_char(char):
if char in string.ascii_letters or char in string.digits or char in string.punctuation or char in string.whitespace:
return char
else:
return r'\x%02x' % ord(char)
def convert_to_printable(s):
return ''.join([convert_char(c) for c in s])
if hasattr(self, 'VS_VERSIONINFO'):
dump.add_header('Version Information')
dump.add_lines(self.VS_VERSIONINFO.dump())
dump.add_newline()
if hasattr(self, 'VS_FIXEDFILEINFO'):
dump.add_lines(self.VS_FIXEDFILEINFO.dump())
dump.add_newline()
if hasattr(self, 'FileInfo'):
for entry in self.FileInfo:
dump.add_lines(entry.dump())
dump.add_newline()
if hasattr(entry, 'StringTable'):
for st_entry in entry.StringTable:
[dump.add_line(' '+line) for line in st_entry.dump()]
dump.add_line(' LangID: '+st_entry.LangID)
dump.add_newline()
for str_entry in st_entry.entries.items():
dump.add_line( ' ' +
convert_to_printable(str_entry[0]) + ': ' +
convert_to_printable(str_entry[1]) )
dump.add_newline()
elif hasattr(entry, 'Var'):
for var_entry in entry.Var:
if hasattr(var_entry, 'entry'):
[dump.add_line(' '+line) for line in var_entry.dump()]
dump.add_line(
' ' +
convert_to_printable(var_entry.entry.keys()[0]) +
': ' + var_entry.entry.values()[0])
dump.add_newline()
if hasattr(self, 'DIRECTORY_ENTRY_EXPORT'):
dump.add_header('Exported symbols')
dump.add_lines(self.DIRECTORY_ENTRY_EXPORT.struct.dump())
dump.add_newline()
dump.add_line('%-10s %-10s %s' % ('Ordinal', 'RVA', 'Name'))
for export in self.DIRECTORY_ENTRY_EXPORT.symbols:
dump.add('%-10d 0x%08Xh %s' % (
export.ordinal, export.address, export.name))
if export.forwarder:
dump.add_line(' forwarder: %s' % export.forwarder)
else:
dump.add_newline()
dump.add_newline()
if hasattr(self, 'DIRECTORY_ENTRY_IMPORT'):
dump.add_header('Imported symbols')
for module in self.DIRECTORY_ENTRY_IMPORT:
dump.add_lines(module.struct.dump())
dump.add_newline()
for symbol in module.imports:
if symbol.import_by_ordinal is True:
dump.add('%s Ordinal[%s] (Imported by Ordinal)' % (
module.dll, str(symbol.ordinal)))
else:
dump.add('%s.%s Hint[%s]' % (
module.dll, symbol.name, str(symbol.hint)))
if symbol.bound:
dump.add_line(' Bound: 0x%08X' % (symbol.bound))
else:
dump.add_newline()
dump.add_newline()
if hasattr(self, 'DIRECTORY_ENTRY_BOUND_IMPORT'):
dump.add_header('Bound imports')
for bound_imp_desc in self.DIRECTORY_ENTRY_BOUND_IMPORT:
dump.add_lines(bound_imp_desc.struct.dump())
dump.add_line('DLL: %s' % bound_imp_desc.name)
dump.add_newline()
for bound_imp_ref in bound_imp_desc.entries:
dump.add_lines(bound_imp_ref.struct.dump(), 4)
dump.add_line('DLL: %s' % bound_imp_ref.name, 4)
dump.add_newline()
if hasattr(self, 'DIRECTORY_ENTRY_DELAY_IMPORT'):
dump.add_header('Delay Imported symbols')
for module in self.DIRECTORY_ENTRY_DELAY_IMPORT:
dump.add_lines(module.struct.dump())
dump.add_newline()
for symbol in module.imports:
if symbol.import_by_ordinal is True:
dump.add('%s Ordinal[%s] (Imported by Ordinal)' % (
module.dll, str(symbol.ordinal)))
else:
dump.add('%s.%s Hint[%s]' % (
module.dll, symbol.name, str(symbol.hint)))
if symbol.bound:
dump.add_line(' Bound: 0x%08X' % (symbol.bound))
else:
dump.add_newline()
dump.add_newline()
if hasattr(self, 'DIRECTORY_ENTRY_RESOURCE'):
dump.add_header('Resource directory')
dump.add_lines(self.DIRECTORY_ENTRY_RESOURCE.struct.dump())
for resource_type in self.DIRECTORY_ENTRY_RESOURCE.entries:
if resource_type.name is not None:
dump.add_line('Name: [%s]' % resource_type.name, 2)
else:
dump.add_line('Id: [0x%X] (%s)' % (
resource_type.struct.Id, RESOURCE_TYPE.get(
resource_type.struct.Id, '-')),
2)
dump.add_lines(resource_type.struct.dump(), 2)
if hasattr(resource_type, 'directory'):
dump.add_lines(resource_type.directory.struct.dump(), 4)
for resource_id in resource_type.directory.entries:
if resource_id.name is not None:
dump.add_line('Name: [%s]' % resource_id.name, 6)
else:
dump.add_line('Id: [0x%X]' % resource_id.struct.Id, 6)
dump.add_lines(resource_id.struct.dump(), 6)
if hasattr(resource_id, 'directory'):
dump.add_lines(resource_id.directory.struct.dump(), 8)
for resource_lang in resource_id.directory.entries:
# dump.add_line('\\--- LANG [%d,%d][%s]' % (
# resource_lang.data.lang,
# resource_lang.data.sublang,
# LANG[resource_lang.data.lang]), 8)
dump.add_lines(resource_lang.struct.dump(), 10)
dump.add_lines(resource_lang.data.struct.dump(), 12)
dump.add_newline()
dump.add_newline()
if ( hasattr(self, 'DIRECTORY_ENTRY_TLS') and
self.DIRECTORY_ENTRY_TLS and
self.DIRECTORY_ENTRY_TLS.struct ):
dump.add_header('TLS')
dump.add_lines(self.DIRECTORY_ENTRY_TLS.struct.dump())
dump.add_newline()
if hasattr(self, 'DIRECTORY_ENTRY_DEBUG'):
dump.add_header('Debug information')
for dbg in self.DIRECTORY_ENTRY_DEBUG:
dump.add_lines(dbg.struct.dump())
try:
dump.add_line('Type: '+DEBUG_TYPE[dbg.struct.Type])
except KeyError:
dump.add_line('Type: 0x%x(Unknown)' % dbg.struct.Type)
dump.add_newline()
if hasattr(self, 'DIRECTORY_ENTRY_BASERELOC'):
dump.add_header('Base relocations')
for base_reloc in self.DIRECTORY_ENTRY_BASERELOC:
dump.add_lines(base_reloc.struct.dump())
for reloc in base_reloc.entries:
try:
dump.add_line('%08Xh %s' % (
reloc.rva, RELOCATION_TYPE[reloc.type][16:]), 4)
except KeyError:
dump.add_line('0x%08X 0x%x(Unknown)' % (
reloc.rva, reloc.type), 4)
dump.add_newline()
return dump.get_text()
# OC Patch
def get_physical_by_rva(self, rva):
"""Gets the physical address in the PE file from an RVA value."""
try:
return self.get_offset_from_rva(rva)
except Exception:
return None
##
# Double-Word get/set
##
def get_data_from_dword(self, dword):
"""Return a four byte string representing the double word value. (little endian)."""
return struct.pack('<L', dword & 0xffffffff)
def get_dword_from_data(self, data, offset):
"""Convert four bytes of data to a double word (little endian)
'offset' is assumed to index into a dword array. So setting it to
N will return a dword out of the data sarting at offset N*4.
Returns None if the data can't be turned into a double word.
"""
if (offset+1)*4 > len(data):
return None
return struct.unpack('<L', data[offset*4:(offset+1)*4])[0]
def get_dword_at_rva(self, rva):
"""Return the double word value at the given RVA.
Returns None if the value can't be read, i.e. the RVA can't be mapped
to a file offset.
"""
try:
return self.get_dword_from_data(self.get_data(rva)[:4], 0)
except PEFormatError:
return None
def get_dword_from_offset(self, offset):
"""Return the double word value at the given file offset. (little endian)"""
if offset+4 > len(self.__data__):
return None
return self.get_dword_from_data(self.__data__[offset:offset+4], 0)
def set_dword_at_rva(self, rva, dword):
"""Set the double word value at the file offset corresponding to the given RVA."""
return self.set_bytes_at_rva(rva, self.get_data_from_dword(dword))
def set_dword_at_offset(self, offset, dword):
"""Set the double word value at the given file offset."""
return self.set_bytes_at_offset(offset, self.get_data_from_dword(dword))
##
# Word get/set
##
def get_data_from_word(self, word):
"""Return a two byte string representing the word value. (little endian)."""
return struct.pack('<H', word)
def get_word_from_data(self, data, offset):
"""Convert two bytes of data to a word (little endian)
'offset' is assumed to index into a word array. So setting it to
N will return a dword out of the data sarting at offset N*2.
Returns None if the data can't be turned into a word.
"""
if (offset+1)*2 > len(data):
return None
return struct.unpack('<H', data[offset*2:(offset+1)*2])[0]
def get_word_at_rva(self, rva):
"""Return the word value at the given RVA.
Returns None if the value can't be read, i.e. the RVA can't be mapped
to a file offset.
"""
try:
return self.get_word_from_data(self.get_data(rva)[:2], 0)
except PEFormatError:
return None
def get_word_from_offset(self, offset):
"""Return the word value at the given file offset. (little endian)"""
if offset+2 > len(self.__data__):
return None
return self.get_word_from_data(self.__data__[offset:offset+2], 0)
def set_word_at_rva(self, rva, word):
"""Set the word value at the file offset corresponding to the given RVA."""
return self.set_bytes_at_rva(rva, self.get_data_from_word(word))
def set_word_at_offset(self, offset, word):
"""Set the word value at the given file offset."""
return self.set_bytes_at_offset(offset, self.get_data_from_word(word))
##
# Quad-Word get/set
##
def get_data_from_qword(self, word):
"""Return a eight byte string representing the quad-word value. (little endian)."""
return struct.pack('<Q', word)
def get_qword_from_data(self, data, offset):
"""Convert eight bytes of data to a word (little endian)
'offset' is assumed to index into a word array. So setting it to
N will return a dword out of the data sarting at offset N*8.
Returns None if the data can't be turned into a quad word.
"""
if (offset+1)*8 > len(data):
return None
return struct.unpack('<Q', data[offset*8:(offset+1)*8])[0]
def get_qword_at_rva(self, rva):
"""Return the quad-word value at the given RVA.
Returns None if the value can't be read, i.e. the RVA can't be mapped
to a file offset.
"""
try:
return self.get_qword_from_data(self.get_data(rva)[:8], 0)
except PEFormatError:
return None
def get_qword_from_offset(self, offset):
"""Return the quad-word value at the given file offset. (little endian)"""
if offset+8 > len(self.__data__):
return None
return self.get_qword_from_data(self.__data__[offset:offset+8], 0)
def set_qword_at_rva(self, rva, qword):
"""Set the quad-word value at the file offset corresponding to the given RVA."""
return self.set_bytes_at_rva(rva, self.get_data_from_qword(qword))
def set_qword_at_offset(self, offset, qword):
"""Set the quad-word value at the given file offset."""
return self.set_bytes_at_offset(offset, self.get_data_from_qword(qword))
##
# Set bytes
##
def set_bytes_at_rva(self, rva, data):
"""Overwrite, with the given string, the bytes at the file offset corresponding to the given RVA.
Return True if successful, False otherwise. It can fail if the
offset is outside the file's boundaries.
"""
offset = self.get_physical_by_rva(rva)
if not offset:
raise False
return self.set_bytes_at_offset(offset, data)
def set_bytes_at_offset(self, offset, data):
"""Overwrite the bytes at the given file offset with the given string.
Return True if successful, False otherwise. It can fail if the
offset is outside the file's boundaries.
"""
if not isinstance(data, str):
raise TypeError('data should be of type: str')
if offset >= 0 and offset < len(self.__data__):
self.__data__ = ( self.__data__[:offset] +
data +
self.__data__[offset+len(data):] )
else:
return False
self.update_all_section_data()
return True
def update_all_section_data(self):
"""Refresh the data of all section in the file.
Will call update_section_data() for each section in the file.
"""
for section in self.sections:
self.update_section_data(section)
def update_section_data(self, section):
"""Update the section data with any data updated in the file.
If the file's data is modified, the section's data can be refreshed
by invoking this method.
"""
# Refresh the section's data with the modified information
#
section_data_start = section.PointerToRawData
section_data_end = section_data_start+section.SizeOfRawData
section.set_data(self.__data__[section_data_start:section_data_end])
def relocate_image(self, new_ImageBase):
"""Apply the relocation information to the image using the provided new image base.
This method will apply the relocation information to the image. Given the new base,
all the relocations will be processed and both the raw data and the section's data
will be fixed accordingly.
The resulting image can be retrieved as well through the method:
get_memory_mapped_image()
In order to get something that would more closely match what could be found in memory
once the Windows loader finished its work.
"""
relocation_difference = new_ImageBase - self.OPTIONAL_HEADER.ImageBase
for reloc in self.DIRECTORY_ENTRY_BASERELOC:
virtual_address = reloc.struct.VirtualAddress
size_of_block = reloc.struct.SizeOfBlock
# We iterate with an index because if the relocation is of type
# IMAGE_REL_BASED_HIGHADJ we need to also process the next entry
# at once and skip it for the next interation
#
entry_idx = 0
while entry_idx<len(reloc.entries):
entry = reloc.entries[entry_idx]
entry_idx += 1
if entry.type == RELOCATION_TYPE['IMAGE_REL_BASED_ABSOLUTE']:
# Nothing to do for this type of relocation
pass
elif entry.type == RELOCATION_TYPE['IMAGE_REL_BASED_HIGH']:
# Fix the high 16bits of a relocation
#
# Add high 16bits of relocation_difference to the
# 16bit value at RVA=entry.rva
self.set_word_at_rva(
entry.rva,
( self.get_word_at_rva(entry.rva) + relocation_difference>>16)&0xffff )
elif entry.type == RELOCATION_TYPE['IMAGE_REL_BASED_LOW']:
# Fix the low 16bits of a relocation
#
# Add low 16 bits of relocation_difference to the 16bit value
# at RVA=entry.rva
self.set_word_at_rva(
entry.rva,
( self.get_word_at_rva(entry.rva) + relocation_difference)&0xffff)
elif entry.type == RELOCATION_TYPE['IMAGE_REL_BASED_HIGHLOW']:
# Handle all high and low parts of a 32bit relocation
#
# Add relocation_difference to the value at RVA=entry.rva
self.set_dword_at_rva(
entry.rva,
self.get_dword_at_rva(entry.rva)+relocation_difference)
elif entry.type == RELOCATION_TYPE['IMAGE_REL_BASED_HIGHADJ']:
# Fix the high 16bits of a relocation and adjust
#
# Add high 16bits of relocation_difference to the 32bit value
# composed from the (16bit value at RVA=entry.rva)<<16 plus
# the 16bit value at the next relocation entry.
#
# If the next entry is beyond the array's limits,
# abort... the table is corrupt
#
if entry_idx == len(reloc.entries):
break
next_entry = reloc.entries[entry_idx]
entry_idx += 1
self.set_word_at_rva( entry.rva,
((self.get_word_at_rva(entry.rva)<<16) + next_entry.rva +
relocation_difference & 0xffff0000) >> 16 )
elif entry.type == RELOCATION_TYPE['IMAGE_REL_BASED_DIR64']:
# Apply the difference to the 64bit value at the offset
# RVA=entry.rva
self.set_qword_at_rva(
entry.rva,
self.get_qword_at_rva(entry.rva) + relocation_difference)
def verify_checksum(self):
return self.OPTIONAL_HEADER.CheckSum == self.generate_checksum()
def generate_checksum(self):
# This will make sure that the data represeting the PE image
# is updated with any changes that might have been made by
# assigning values to header fields as those are not automatically
# updated upon assignment.
#
self.__data__ = self.write()
# Get the offset to the CheckSum field in the OptionalHeader
#
checksum_offset = self.OPTIONAL_HEADER.__file_offset__ + 0x40 # 64
checksum = 0
for i in range( len(self.__data__) / 4 ):
# Skip the checksum field
#
if i == checksum_offset / 4:
continue
dword = struct.unpack('L', self.__data__[ i*4 : i*4+4 ])[0]
checksum = (checksum & 0xffffffff) + dword + (checksum>>32)
if checksum > 2**32:
checksum = (checksum & 0xffffffff) + (checksum >> 32)
checksum = (checksum & 0xffff) + (checksum >> 16)
checksum = (checksum) + (checksum >> 16)
checksum = checksum & 0xffff
return checksum + len(self.__data__)