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malware.py
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malware.py
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# Volatility
#
# Authors:
# Michael Hale Ligh <[email protected]>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or (at
# your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
import os, sys, string, struct, subprocess, binascii, time, re
from operator import itemgetter
from bisect import bisect_right
import volatility.debug as debug
import volatility.obj as obj
import volatility.plugins.procdump as procdump
import volatility.win32.tasks as tasks
import volatility.win32.modules as modules
import volatility.commands as commands
import volatility.utils as utils
import volatility.plugins.ssdt as ssdt
import volatility.plugins.filescan as filescan
import volatility.scan as scan
import volatility.plugins.modscan as modscan
import volatility.plugins.taskmods as taskmods
import volatility.plugins.overlays.windows.windows as windows
#--------------------------------------------------------------------------------
# dependents
#--------------------------------------------------------------------------------
try:
import yara
except ImportError:
print "YARA is not installed, see http://code.google.com/p/yara-project/"
try:
import distorm3
except ImportError:
print 'distorm3 is not installed, see http://code.google.com/p/distorm/'
#--------------------------------------------------------------------------------
# memory protection flags from nt!MmProtectToValue
#--------------------------------------------------------------------------------
PROTECT_FLAGS = [
'PAGE_NOACCESS',
'PAGE_READONLY',
'PAGE_EXECUTE',
'PAGE_EXECUTE_READ',
'PAGE_READWRITE',
'PAGE_WRITECOPY',
'PAGE_EXECUTE_READWRITE',
'PAGE_EXECUTE_WRITECOPY',
'PAGE_NOACCESS',
'PAGE_NOCACHE | PAGE_READONLY',
'PAGE_NOCACHE | PAGE_EXECUTE',
'PAGE_NOCACHE | PAGE_EXECUTE_READ',
'PAGE_NOCACHE | PAGE_READWRITE',
'PAGE_NOCACHE | PAGE_WRITECOPY',
'PAGE_NOCACHE | PAGE_EXECUTE_READWRITE',
'PAGE_NOCACHE | PAGE_EXECUTE_WRITECOPY',
'PAGE_NOACCESS',
'PAGE_GUARD | PAGE_READONLY',
'PAGE_GUARD | PAGE_EXECUTE',
'PAGE_GUARD | PAGE_EXECUTE_READ',
'PAGE_GUARD | PAGE_READWRITE',
'PAGE_GUARD | PAGE_WRITECOPY',
'PAGE_GUARD | PAGE_EXECUTE_READWRITE',
'PAGE_GUARD | PAGE_EXECUTE_WRITECOPY',
'PAGE_NOACCESS',
'PAGE_WRITECOMBINE | PAGE_READONLY',
'PAGE_WRITECOMBINE | PAGE_EXECUTE',
'PAGE_WRITECOMBINE | PAGE_EXECUTE_READ',
'PAGE_WRITECOMBINE | PAGE_READWRITE',
'PAGE_WRITECOMBINE | PAGE_WRITECOPY',
'PAGE_WRITECOMBINE | PAGE_EXECUTE_READWRITE',
'PAGE_WRITECOMBINE | PAGE_EXECUTE_WRITECOPY',
]
#--------------------------------------------------------------------------------
# Special data types not in the public symbol files
#--------------------------------------------------------------------------------
malware_types = {
#
# Types for the svcscan plugin (XP only)
#
'_SERVICE_LIST_ENTRY' : [ 0x8, {
'Blink' : [ 0x0, ['pointer', ['_SERVICE_RECORD_LEGACY']]],
'Flink' : [ 0x4, ['pointer', ['_SERVICE_RECORD_LEGACY']]],
} ],
'_SERVICE_RECORD_LEGACY' : [ 0x70, {
'ServiceList' : [ 0x0, ['_SERVICE_LIST_ENTRY']],
'ServiceName' : [ 0x8, ['pointer', ['unsigned short']]],
'DisplayName' : [ 0xc, ['pointer', ['unsigned short']]],
'Order' : [ 0x10, ['int']],
'TagSignature' : [ 0x18, ['int']],
'Binary1' : [ 0x24, ['pointer', ['unsigned short']]],
'Binary2' : [ 0x24, ['pointer', ['_SERVICE_BINARY_LEGACY']]],
'Type' : [ 0x28, ['int']],
'State' : [ 0x2c, ['int']],
} ],
'_SERVICE_BINARY_LEGACY' : [ 0x14, {
'ServicePath' : [ 0x8, ['pointer', ['unsigned short']]],
'ProcessId' : [ 0xc, ['int']],
} ],
#
# Types for the svcscan plugin (Vista and 7)
#
'_SERVICE_HEADER': [ None, {
# Signature of "serH"
'Tag': [ 0x0, ['array', 4, ['unsigned char']]],
# Pointer to the main record
'Ser': [ 0xC, ['pointer', ['_SERVICE_RECORD']]],
} ],
'_SERVICE_RECORD': [ None, {
# Previous entry in the singly linked list
'PrevEntry': [ 0x0, ['pointer', ['_SERVICE_RECORD']]],
# The service's name
'ServiceName': [ 0x4, ['pointer', ['unsigned short']]],
# The service's display name
'DisplayName': [ 0x8, ['pointer', ['unsigned short']]],
# The unique order number of the service
'Order': [ 0xC, ['unsigned int']],
# Union which is LPWSTR for drivers or points to another struct for processes
'Binary2': [ 0x1C, ['pointer', ['_SERVICE_BINARY']]],
'Binary1': [ 0x1C, ['pointer', ['unsigned char']]],
# The service type (kernel driver, own process, shared process, etc)
'Type': [ 0x20, ['unsigned int']],
# The service state (running, stopped, paused, etc)
'State': [ 0x24, ['unsigned int']],
} ],
'_SERVICE_BINARY': [ None, {
# The load path of the service binary, includes command line arguments
'ServicePath': [ 0x8, ['pointer', ['unsigned short']]],
# Process ID if the service is active
'ProcessId': [ 0xC, ['unsigned int']],
} ],
#
# Types for the csrpslist plugin
#
'_CSR_PROCESS_POINTER' : [ None, {
'CsrRootProcess' : [ 0x0, ['pointer', ['pointer', ['_CSR_PROCESS']]]],
} ],
'_CSR_PROCESS' : [ 0x60, {
'ClientId' : [ 0x0, ['_CLIENT_ID']],
'ListLink' : [ 0x8, ['_LIST_ENTRY']],
'ThreadList' : [ 0x10, ['_LIST_ENTRY']],
'NtSession' : [ 0x18, ['pointer', ['_CSR_NT_SESSION']]],
'ClientPort' : [ 0x1c, ['pointer', ['void']]],
'ClientViewBase' : [ 0x20, ['pointer', ['unsigned char']]],
'ClientViewBounds' : [ 0x24, ['pointer', ['unsigned char']]],
'ProcessHandle' : [ 0x28, ['pointer', ['void']]],
'SequenceNumber' : [ 0x2c, ['unsigned long']],
'Flags' : [ 0x30, ['unsigned long']],
'DebugFlags' : [ 0x34, ['unsigned long']],
'ReferenceCount' : [ 0x38, ['unsigned long']],
'ProcessGroupId' : [ 0x3c, ['unsigned long']],
'ProcessGroupSequence' : [ 0x40, ['unsigned long']],
'LastMessageSequence' : [ 0x44, ['unsigned long']],
'NumOutstandingMessages' : [ 0x48, ['unsigned long']],
'ShutdownLevel' : [ 0x4c, ['unsigned long']],
'ShutdownFlags' : [ 0x50, ['unsigned long']],
'Luid' : [ 0x54, ['_LUID']],
'ServerDllPerProcessData' : [ 0x5c, ['array', 1, ['pointer', ['void']]]],
} ],
'_CSR_THREAD' : [ 0x38, {
'CreateTime' : [ 0x0, ['_LARGE_INTEGER']],
'Link' : [ 0x8, ['_LIST_ENTRY']],
'HashLinks' : [ 0x10, ['_LIST_ENTRY']],
'ClientId' : [ 0x18, ['_CLIENT_ID']],
'Process' : [ 0x20, ['pointer', ['_CSR_PROCESS']]],
'ThreadHandle' : [ 0x24, ['pointer', ['void']]],
'Flags' : [ 0x28, ['unsigned long']],
'ReferenceCount' : [ 0x2c, ['unsigned long']],
'ImpersonateCount' : [ 0x30, ['unsigned long']],
} ],
'_CSR_NT_SESSION' : [ 0x18, {
'SessionLink' : [ 0x0, ['_LIST_ENTRY']],
'SessionId' : [ 0x8, ['unsigned long']],
'ReferenceCount' : [ 0xc, ['unsigned long']],
'RootDirectory' : [ 0x10, ['_STRING']],
} ],
#
# Types for pe file header parsing
#
'_IMAGE_EXPORT_DIRECTORY': [ 0x28, {
'Base': [ 0x10, ['unsigned int']],
'NumberOfFunctions': [ 0x14, ['unsigned int']],
'NumberOfNames': [ 0x18, ['unsigned int']],
'AddressOfFunctions': [ 0x1C, ['unsigned int']],
'AddressOfNames': [ 0x20, ['unsigned int']],
'AddressOfNameOrdinals': [ 0x24, ['unsigned int']],
} ],
'_IMAGE_IMPORT_DESCRIPTOR': [ 0x14, {
'OriginalFirstThunk': [ 0x0, ['unsigned int']],
'TimeDateStamp': [ 0x4, ['unsigned int']],
'ForwarderChain': [ 0x8, ['unsigned int']],
'Name': [ 0xC, ['unsigned int']],
'FirstThunk': [ 0x10, ['pointer', ['unsigned int']]],
} ],
'_IMAGE_THUNK_DATA' : [ 0x4, {
'AddressOfData' : [ 0x0, ['unsigned int']],
} ],
'_IMAGE_IMPORT_BY_NAME' : [ None, {
'Hint' : [ 0x0, ['unsigned short']],
'Name' : [ 0x2, ['array', 20, ['unsigned char']]],
} ],
'_IMAGE_SECTION_HEADER' : [ None, {
'Name' : [ 0x0, ['String', dict(length = 8)]],
}],
#
# Types for callbacks (Thanks to Frank Boldewin for some clues)
#
'_NOTIFICATION_PACKET' : [ 0x10, {
'ListEntry' : [ 0x0, ['_LIST_ENTRY']],
'DriverObject' : [ 0x8, ['pointer', ['_DRIVER_OBJECT']]],
'NotificationRoutine' : [ 0xC, ['unsigned int']],
} ],
'_KBUGCHECK_CALLBACK_RECORD' : [ 0x20, {
'Entry' : [ 0x0, ['_LIST_ENTRY']],
'CallbackRoutine' : [ 0x8, ['unsigned int']],
'Buffer' : [ 0xC, ['pointer', ['void']]],
'Length' : [ 0x10, ['unsigned int']],
'Component' : [ 0x14, ['pointer', ['unsigned char']]],
'Checksum' : [ 0x18, ['pointer', ['unsigned int']]],
'State' : [ 0x1C, ['unsigned char']],
} ],
'_KBUGCHECK_REASON_CALLBACK_RECORD' : [ 0x1C, {
'Entry' : [ 0x0, ['_LIST_ENTRY']],
'CallbackRoutine' : [ 0x8, ['unsigned int']],
'Component' : [ 0xC, ['pointer', ['unsigned char']]],
'Checksum' : [ 0x10, ['pointer', ['unsigned int']]],
'Reason' : [ 0x14, ['unsigned int']],
'State' : [ 0x18, ['unsigned char']],
} ],
'_SHUTDOWN_PACKET' : [ 0xC, {
'Entry' : [ 0x0, ['_LIST_ENTRY']],
'DeviceObject' : [ 0x8, ['pointer', ['_DEVICE_OBJECT']]],
} ],
'_EX_CALLBACK_ROUTINE_BLOCK' : [ 0x8, {
'RundownProtect' : [ 0x0, ['unsigned int']], \
'Function' : [ 0x4, ['unsigned int']], \
'Context' : [ 0x8, ['unsigned int']], \
} ],
'_GENERIC_CALLBACK' : [ 0xC, {
'Callback' : [ 0x4, ['pointer', ['void']]],
'Associated' : [ 0x8, ['pointer', ['void']]],
} ],
'_REGISTRY_CALLBACK_LEGACY' : [ 0x38, {
'CreateTime' : [ 0x0, ['WinTimeStamp', {}]],
} ],
'_REGISTRY_CALLBACK' : [ None, {
'ListEntry' : [ 0x0, ['_LIST_ENTRY']],
'Function' : [ 0x1C, ['pointer', ['void']]],
} ],
'_DBGPRINT_CALLBACK' : [ 0x14, {
'Function' : [ 0x8, ['pointer', ['void']]],
} ],
'_SEG_DESCRIPTOR' : [ 0x8, {
'size1': [ 0x0, ['BitField', dict(start_bit = 0, end_bit = 16)]],
'baseaddress1': [ 0x2, ['BitField', dict(start_bit = 0, end_bit = 16)]],
'baseaddress2': [ 0x4, ['BitField', dict(start_bit = 0, end_bit = 8)]],
'type': [ 0x4, ['BitField', dict(start_bit = 8, end_bit = 12)]],
'sFlag': [ 0x4, ['BitField', dict(start_bit = 12, end_bit = 13)]],
'dpl': [ 0x4, ['BitField', dict(start_bit = 13, end_bit = 15)]],
'pFlag': [ 0x4, ['BitField', dict(start_bit = 15, end_bit = 16)]],
'size2': [ 0x6, ['BitField', dict(start_bit = 0, end_bit = 4)]],
'notused': [ 0x6, ['BitField', dict(start_bit = 4, end_bit = 5)]],
'lFlag': [ 0x6, ['BitField', dict(start_bit = 5, end_bit = 6)]],
'DB': [ 0x6, ['BitField', dict(start_bit = 6, end_bit = 7)]],
'gFlag': [ 0x6, ['BitField', dict(start_bit = 7, end_bit = 8)]],
'baseaddress3': [ 0x6, ['BitField', dict(start_bit = 8, end_bit = 16)]],
} ],
'_CALL_GATE_DESCRIPTOR' : [ 0x8, {
'offset1': [ 0x0, ['BitField', dict(start_bit = 0, end_bit = 16)]],
'selector': [ 0x2, ['BitField', dict(start_bit = 0, end_bit = 16)]],
'argcount': [ 0x4, ['BitField', dict(start_bit = 0, end_bit = 5)]],
'zeroes': [ 0x4, ['BitField', dict(start_bit = 5, end_bit = 8)]],
'type': [ 0x4, ['BitField', dict(start_bit = 8, end_bit = 12)]],
'sFlag': [ 0x4, ['BitField', dict(start_bit = 12, end_bit = 13)]],
'dpl': [ 0x4, ['BitField', dict(start_bit = 13, end_bit = 15)]],
'pFlag': [ 0x4, ['BitField', dict(start_bit = 15, end_bit = 16)]],
'offset2': [ 0x6, ['BitField', dict(start_bit = 0, end_bit = 16)]],
} ],
}
#--------------------------------------------------------------------------------
# Symbol classes used with API hooks etc
#--------------------------------------------------------------------------------
class Symbol:
def __init__(self, owner_mod=None, ordinal=None, funcaddr=None, name=None, forwarder=None, dll=None):
self.owner_mod = owner_mod
self.ordinal = ordinal
self.funcaddr = funcaddr & 0xFFFFFFFF
self.name = name
self.forwarder = forwarder
def get_name(self):
"""Returns the function name, its ordinal value, or UNKNOWN"""
if self.name != None and self.name != "":
return self.name
elif self.ordinal != None:
return hex(self.ordinal)
else:
return 'UNKNOWN'
def get_instruction(self, instruction_number = 0):
"""Returns the Nth instruction at an API's start address"""
data = self.owner_mod.obj_vm.zread(self.funcaddr, (instruction_number + 1) * 12)
c = 0
for op in distorm3.Decompose(self.funcaddr, data, distorm3.Decode32Bits):
if not op.valid:
break
if c == instruction_number:
return op
c += 1
class ExportedSymbol(Symbol):
pass
class ImportedSymbol(Symbol):
pass
#--------------------------------------------------------------------------------
# Extensions of Volatility objects - stable on all OS
#--------------------------------------------------------------------------------
class _IMAGE_IMPORT_DESCRIPTOR(obj.CType):
"""Handles IID entries for imported functions"""
def __init__(self, theType = None, offset = None, vm = None, parent = None, *args, **kwargs):
self.sectoffset = offset
obj.CType.__init__(self, theType = theType, offset = offset, vm = vm, parent = parent, *args, **kwargs)
def is_list_end(self):
"""Returns True if we've reached the list end (a struct with all zeroes)"""
data = self.obj_vm.zread(self.obj_offset, self.obj_vm.profile.get_obj_size('_IMAGE_IMPORT_DESCRIPTOR'))
if data.count(chr(0)) == len(data):
return True
return False
def get_name(self):
"""Returns the name of the DLL for this IID"""
###This try block is for http://code.google.com/p/volatility/issues/detail?id=57
try:
va = self.obj_parent.DllBase + self.Name
except:
return ''
if self.obj_vm.is_valid_address(va):
return read_asciiz(self.obj_vm, va)
else:
return ''
def get_table(self, thunk_va):
"""Generator for ITD structures"""
i = 0
thunk_size = self.obj_vm.profile.get_obj_size('_IMAGE_THUNK_DATA')
while True:
thunk = obj.Object('_IMAGE_THUNK_DATA', offset = thunk_va + (i*thunk_size), vm = self.obj_vm)
if not thunk or not thunk.AddressOfData:
break
yield thunk
i += 1
def get_imports(self):
"""Generator for enumerating imported functions"""
mod_base = self.obj_parent.DllBase
dll = self.get_name()
if not is_valid_dos_filename(dll):
dll = '*invalid*'
try:
# The lookup table, contains function names
ilt = list(self.get_table(mod_base + self.OriginalFirstThunk))
# The address table, contains bound addresses
iat = list(self.get_table(mod_base + self.FirstThunk))
except:
raise StopIteration('Invalid')
# We can use either ilt or iat here, doesn't really matter
table = ilt
for i in xrange(len(table)):
#print i, table[i], table[i].AddressOfData
imp_ord = imp_name = None
if table[i].AddressOfData & IMAGE_ORDINAL_FLAG:
imp_ord = table[i].AddressOfData & 0xffff
else:
imp_name = read_asciiz(self.obj_vm, mod_base + table[i].AddressOfData + 2)
if not is_valid_function_name(imp_name):
imp_name = "*invalid*"
imp_address = self.FirstThunk + mod_base + i * 4
imp_bound = obj.Object('unsigned int', offset = imp_address, vm = self.obj_vm)
if imp_bound:
imp = ImportedSymbol(
owner_mod = self.obj_parent,
ordinal = imp_ord,
funcaddr = imp_bound,
name = imp_name,
forwarder = None)
yield dll, imp
class _IMAGE_EXPORT_DIRECTORY(obj.CType):
"""Handles IED entries for exported functions"""
def __init__(self, theType = None, offset = None, vm = None, parent = None, *args, **kwargs):
self.sectoffset = offset
obj.CType.__init__(self, theType = theType, offset = offset, vm = vm, parent = parent, *args, **kwargs)
def get_forwarder(self, mod_base, func_rva):
"""If we are dealing with forwarded exports, return the name of the target function"""
return None
exp_addr = self.obj_parent.VirtualAddress
exp_size = self.obj_parent.Size
if func_rva >= exp_addr and func_rva < exp_addr + exp_size:
return self.read_asciiz(mod_base + func_rva)
else:
return None
def get_exports(self):
"""Generator for exported functions"""
mod_base = self.obj_parent.DllBase
seen_ordinals = []
address_of_functions = obj.Object('Array', vm = self.obj_vm, \
offset = mod_base + self.AddressOfFunctions, targetType = 'unsigned int', count = self.NumberOfFunctions)
address_of_names = obj.Object('Array', vm = self.obj_vm, \
offset = mod_base + self.AddressOfNames, targetType = 'unsigned int', count = self.NumberOfNames)
address_of_name_ordinals = obj.Object('Array', vm = self.obj_vm, \
offset = mod_base + self.AddressOfNameOrdinals, targetType = 'unsigned short', count = self.NumberOfNames)
# Handle functions exported by name *and* ordinal
for i in range(self.NumberOfNames):
name_rva = address_of_names[i]
ordinal = address_of_name_ordinals[i]
if ordinal == None:
continue
if name_rva == None or name_rva == 0:
continue
if ordinal >= self.NumberOfFunctions:
continue
func_rva = address_of_functions[ordinal]
if func_rva == None or func_rva == 0:
continue
forwarder = self.get_forwarder(mod_base, func_rva)
name = read_asciiz(self.obj_vm, mod_base + name_rva)
ordinal += self.Base
seen_ordinals.append(ordinal)
yield ExportedSymbol(owner_mod = self.obj_parent,
ordinal = ordinal,
funcaddr = mod_base + func_rva,
name = name,
forwarder = forwarder)
# Handle functions exported by ordinal only
for i in range(self.NumberOfFunctions):
ordinal = self.Base + i
if ordinal not in seen_ordinals:
func_rva = address_of_functions[i]
if func_rva == None or func_rva == 0:
continue
forwarder = self.get_forwarder(mod_base, func_rva)
seen_ordinals.append(ordinal)
yield ExportedSymbol(owner_mod = self.obj_parent,
ordinal = ordinal,
funcaddr = mod_base + func_rva,
name = None,
forwarder = forwarder)
class _LDR_DATA_TABLE_ENTRY(obj.CType):
"""Extension for PE files to help enumerate IAT and EAT"""
def __init__(self, theType = None, offset = None, vm = None, parent = None, *args, **kwargs):
self.sectoffset = offset
obj.CType.__init__(self, theType = theType, offset = offset, vm = vm, parent = parent, *args, **kwargs)
def get_nt_header(self):
try:
dos_header = obj.Object("_IMAGE_DOS_HEADER", offset = self.DllBase, vm = self.obj_vm)
return dos_header.get_nt_header()
except ValueError:
return None
def getprocaddress(self, name_to_find):
"""Return the virtual address of a given function exported by a DLL"""
for exp in self.exports():
if exp.get_name() == name_to_find:
return exp.funcaddr
return None
def imports(self, addr_space = None):
if addr_space != None:
self.obj_vm = addr_space
nt_header = self.get_nt_header()
if nt_header == None:
raise StopIteration
imp_addr = nt_header.OptionalHeader.DataDirectory[1].VirtualAddress
imp_size = nt_header.OptionalHeader.DataDirectory[1].Size
if imp_addr > nt_header.OptionalHeader.SizeOfImage or imp_size <= 0:
raise StopIteration
obj_size = self.obj_vm.profile.get_obj_size('_IMAGE_IMPORT_DESCRIPTOR')
i = 0
imps = dict()
while True:
desc = obj.Object('_IMAGE_IMPORT_DESCRIPTOR', vm = self.obj_vm, \
offset = self.DllBase + imp_addr + (i * obj_size), \
parent = self)
if not desc or desc.is_list_end():
break
try:
for dll, imp in desc.get_imports():
if imps.has_key(dll):
imps[dll].append(imp)
else:
imps[dll] = [imp]
except obj.InvalidOffsetError:
pass
i += 1
for dll, symbols in imps.items():
yield dll, symbols
def exports(self, addr_space = None):
if addr_space != None:
self.newattr('obj_vm', addr_space)
nt_header = self.get_nt_header()
if nt_header == None:
raise StopIteration
exp_addr = nt_header.OptionalHeader.DataDirectory[0].VirtualAddress
exp_size = nt_header.OptionalHeader.DataDirectory[0].Size
if exp_addr > nt_header.OptionalHeader.SizeOfImage or exp_size <= 0:
raise StopIteration
exp_dir = obj.Object('_IMAGE_EXPORT_DIRECTORY', vm = self.obj_vm, offset = self.DllBase + exp_addr, parent = self)
if exp_dir != None:
if exp_dir.AddressOfFunctions > nt_header.OptionalHeader.SizeOfImage or \
exp_dir.AddressOfNameOrdinals > nt_header.OptionalHeader.SizeOfImage or \
exp_dir.AddressOfNames > nt_header.OptionalHeader.SizeOfImage or \
exp_dir.NumberOfFunctions > 0x7FFF or exp_dir.NumberOfNames > 0x7FFF:
raise StopIteration
try:
for exp in exp_dir.get_exports():
yield exp
except obj.InvalidOffsetError:
pass
class _EPROCESS(windows._EPROCESS):
def list_modules(self):
if self.UniqueProcessId and self.Peb.Ldr.InLoadOrderModuleList:
for l in self.Peb.Ldr.InLoadOrderModuleList.list_of_type("_LDR_DATA_TABLE_ENTRY", "InLoadOrderLinks"):
yield l
class _IMAGE_DOS_HEADER(obj.CType):
"""DOS header"""
def get_nt_header(self):
"""Get the NT header"""
if self.e_magic != 0x5a4d:
raise ValueError('e_magic {0:04X} is not a valid DOS signature.'.format(self.e_magic))
nt_header = obj.Object("_IMAGE_NT_HEADERS",
offset = self.e_lfanew + self.obj_offset,
vm = self.obj_vm)
if nt_header.Signature != 0x4550:
raise ValueError('NT header signature {0:04X} is not a valid'.format(nt_header.Signature))
return nt_header
class _IMAGE_NT_HEADERS(obj.CType):
"""PE header"""
def get_sections(self, unsafe):
"""Get the PE sections"""
sect_size = self.obj_vm.profile.get_obj_size("_IMAGE_SECTION_HEADER")
start_addr = self.FileHeader.SizeOfOptionalHeader + self.OptionalHeader.obj_offset
for i in range(self.FileHeader.NumberOfSections):
s_addr = start_addr + (i * sect_size)
sect = obj.Object("_IMAGE_SECTION_HEADER", offset = s_addr, vm = self.obj_vm, parent = self)
if not unsafe:
sect.sanity_check_section()
yield sect
class _IMAGE_SECTION_HEADER(obj.CType):
"""PE section"""
def sanity_check_section(self):
"""Sanity checks address boundaries"""
# Note: all addresses here are RVAs
image_size = self.obj_parent.OptionalHeader.SizeOfImage
if self.VirtualAddress > image_size:
raise ValueError('VirtualAddress {0:08x} is past the end of image.'.format(self.VirtualAddress))
if self.Misc.VirtualSize > image_size:
raise ValueError('VirtualSize {0:08x} is larger than image size.'.format(self.Misc.VirtualSize))
if self.SizeOfRawData > image_size:
raise ValueError('SizeOfRawData {0:08x} is larger than image size.'.format(self.SizeOfRawData))
#--------------------------------------------------------------------------------
# general lib area
#--------------------------------------------------------------------------------
#### This is from pefile
allowed_filename = string.lowercase + string.uppercase + string.digits + "!#$%&'()-@^_`{}~+,.;=[]" + ''.join( [chr(i) for i in range(128, 256)] )
def is_valid_dos_filename(s):
if s is None or s == '' or not isinstance(s, str):
return False
for c in s:
if c not in allowed_filename:
return False
return True
#### This is from pefile
allowed_function_name = string.lowercase + string.uppercase + string.digits + '_?@$()'
def is_valid_function_name(s):
if s is None or s == '' or not isinstance(s, str):
return False
for c in s:
if c not in allowed_function_name:
return False
return True
#### This is from pefile (no 64-bit support currently)
IMAGE_ORDINAL_FLAG = 0x80000000L
def read_asciiz(addr_space, string_address, max=255):
"""Read a NULL-terminated ASCII string in the object's address space"""
if not addr_space.is_valid_address(string_address):
return None
try:
str = addr_space.zread(string_address, max)
return str[:str.index('\x00')]
except:
return None
def wctomb(ptr, addr_space):
"""Read a variable length Unicode buffer and return it as ASCII"""
if not addr_space.is_valid_address(ptr):
return None
try:
ret = addr_space.read(ptr, 128)
except:
return None
length = ret.find("\x00\x00")
ret = ret[0:length]
return ret.replace('\x00', '')
def can_exec(f):
"""Returns true if a memory segment is executable"""
try:
flags = PROTECT_FLAGS[f]
except IndexError:
return False
else:
return flags.find("EXECUTE") != -1
def hd(src, start=0, length=16):
"""Hexdump formula seen at http://code.activestate.com/recipes/142812-hex-dumper"""
FILTER=''.join([(len(repr(chr(x)))==3) and chr(x) or '.' for x in range(256)])
result=[]
for i in xrange(0, len(src), length):
s = src[i:i+length]
hexa = ' '.join(["%02x"%ord(x) for x in s])
printable = s.translate(FILTER)
result.append("0x%08x %-*s %s\n" % (i+start, length*3, hexa, printable))
return ''.join(result)
def find_space(addr_space, procs, mod_base):
"""Search for an address space (usually looking for a GUI process)"""
if addr_space.is_valid_address(mod_base):
return addr_space
for proc in procs:
ps_ad = proc.get_process_address_space()
if ps_ad != None:
if ps_ad.is_valid_address(mod_base):
return ps_ad
return None
def get_disasm_text(data, start, count = 10, stoponret=False):
"""Return a string representation of disassembled instructions"""
ret = ""
n = 0
if sys.modules.has_key('distorm3'):
iterable = distorm3.DecodeGenerator(start, data, distorm3.Decode32Bits)
for (offset, size, instruction, hexdump) in iterable:
if n == count:
break
ret += "%.8x: %-32s %s\n" % (offset, hexdump, instruction)
# Optionally stop when reaching the end of a function
if stoponret and instruction.startswith("RET"):
break
n += 1
return ret
def get_yara_text(data, hits, start):
"""Format YARA hits for viewing. Note: YARA 1.4a matches are different than 1.4"""
ret = ""
if not hits:
return ret
for hit in hits:
ret += "YARA rule: {0}\n".format(hit.rule)
if hit.meta.has_key('description'):
ret += "Description: {0}\n".format(hit.meta['description'])
# Account for the API change from Yara Python 1.4 to 1.4.a
if isinstance(hit.strings, list):
hit_strings = [(key, val) for (key, _, val) in hit.strings]
elif isinstance(hit.strings, dict):
hit_strings = [(key, val) for (key, val) in hit.strings.items()]
else:
return ret
for (key, val) in hit_strings:
makehex = False
for c in val:
if c not in string.printable:
makehex = True
break
if makehex:
val = binascii.hexlify(val)
# Get a temporary buffer of the first 128 characters
buffer = data[key:key+128]
if hit.meta.has_key('null_string'):
if buffer.find("\x00") != -1:
val = buffer[0:buffer.find("\x00")]
ret += "Hit: {0}\n".format(val)
ret += "{0}\n".format(hd(buffer, start+key))
return ret
def get_flags(flags, val):
""" text representation of flags from a dictionary """
if flags.has_key(val):
return flags[val]
else:
return [f for f in flags if (flags[f] | val == val)]
def get_sorted_mods(modlist):
"""Return a tuple of modules (LDR_MODULEs) info"""
mods = {}
for mod in modlist:
# Try using the base name first, otherwise strip the file name from the full path
if not mod.BaseDllName:
name = os.path.basename(str(mod.FullDllName))
else:
name = str(mod.BaseDllName)
mods[mod.DllBase] = (mod, name.lower())
mod_addrs = sorted(mods.keys())
return mods, mod_addrs
def get_mem_size(p, start):
"""Given a starting address in process memory, return the base and size of the region"""
for vad in p.VadRoot.traverse():
if vad == None:
continue
# Find the start and end range
startvpn = vad.StartingVpn << 12
endvpn = ((vad.EndingVpn + 1) << 12) - 1
if startvpn <= start and endvpn > start:
return (startvpn, (endvpn-startvpn))
return None
def find_module(modlist, mod_addrs, addr):
"""Modified version of BDG's binary search for modules. Note that modlist and mod_addrs
must be sorted in order of the module base address."""
pos = bisect_right(mod_addrs, addr) - 1
if pos == -1: return None
mod,name = modlist[mod_addrs[pos]]
if (addr >= mod.DllBase and addr < mod.DllBase + mod.SizeOfImage):
return mod
else:
return None
def find_module_by_name(mods, names):
"""Lookup a module by its name"""
for mod in mods:
if str(mod.BaseDllName).lower() in names:
return mod
return None
def find_module_by_name_ex(mods, names):
"""Lookup a module by its name"""
ret = []
for mod in mods:
for name in names:
if str(mod.BaseDllName).lower() == name.lower():
ret.append(mod)
return ret
def get_vad_data(ps_ad, start, end):
"""Returns the data for a given VAD range. Optimizations by Ryan Smith @ hustlelabs.com"""
range_data = ""
num_pages = (end - start + 1) >> 12
ps_ad_is_valid_address = ps_ad.is_valid_address
ps_ad_read = ps_ad.read
blank_page = '\x00' * 0x1000
pages_one = [(ps_ad_read(start + index * 0x1000, 0x1000) if ps_ad_is_valid_address(start + index * 0x1000) else blank_page) for index in xrange(num_pages)]
if None in pages_one:
pages_one = [a_page if a_page != None else blank_page for a_page in pages_one]
return ''.join(pages_one)
def get_malware_space(config, astype=None):
"""Returns an address space with malware types"""
addr_space = utils.load_as(config, astype) if astype else utils.load_as(config)
for cls in [_IMAGE_IMPORT_DESCRIPTOR, _IMAGE_EXPORT_DIRECTORY, _LDR_DATA_TABLE_ENTRY, _PSP_CID_TABLE, _EPROCESS, _IMAGE_DOS_HEADER, _IMAGE_NT_HEADERS, _IMAGE_SECTION_HEADER]:
addr_space.profile.object_classes[cls.__name__] = cls
addr_space.profile.add_types(malware_types)
return addr_space
def get_obj_name(space, object):
""" Return the name from OBJECT_HEADER """
object_obj = obj.Object("_OBJECT_HEADER", \
offset = object.obj_offset - \
space.profile.get_obj_offset('_OBJECT_HEADER', 'Body'),
vm = space)
object_obj.kas = space
return object_obj.get_object_name() or "(unnamed)"
#--------------------------------------------------------------------------------
# malfind plug-in
#--------------------------------------------------------------------------------
class Malfind(procdump.ProcExeDump):
"[MALWARE] Find hidden and injected code"
def __init__(self, config, *args):
procdump.ProcExeDump.__init__(self, config, *args)
config.add_option('YARA-RULES', short_option='Y', default=None,
help='Use YARA rules in addition to finding injected code')
config.add_option('YARA-RULES-ONLY', short_option='y', default=None,
help='Use YARA rules only')
config.add_option("KERNEL", short_option='K', default=False,
action='store_true', help='Scan kernel modules')
config.add_option("SCAN", short_option = 'S', default=False,
action = 'store_true', help = 'Use PSScan')
def rebuild(self, addr_space, start):
"""Use the ProcExeDump's get_image to rebuild a PE in memory"""
pedata = ''
if not addr_space.is_valid_address(start):
return pedata
for offset, code in self.get_image(sys.stdout, addr_space, start):
# Pad out pedata long enough to contain the new code
pedata += "\x00" * (len(code) + offset - len(pedata))
# Swap out whatever's in pedata so far for the new code
pedata = pedata[:offset] + code + pedata[offset + len(code):]
return pedata
def get_vads(self, proc):
"""Generator for VADs in a process"""
ps_ad = proc.get_process_address_space()
if ps_ad != None:
for vad in proc.VadRoot.traverse():
if vad == None:
continue
# Find the start and end range
start = vad.StartingVpn << 12
end = ((vad.EndingVpn + 1) << 12) - 1
if start > 0xFFFFFFFF or end > (0xFFFFFFFF << 12):
continue
data = get_vad_data(ps_ad, start, end)
if data != "":
yield (ps_ad, start, end, vad.Tag, vad.Flags.Protection >> 24, data)
def calculate(self):
rules = None
config = self._config
if config.DUMP_DIR == None:
debug.error("Please specify a dump directory (--dump-dir)")
if not os.path.isdir(config.DUMP_DIR):
debug.error(config.DUMP_DIR + " is not a directory")
if config.YARA_RULES != None or config.YARA_RULES_ONLY != None:
if sys.modules.has_key('yara'):
stuff = config.YARA_RULES if config.YARA_RULES else config.YARA_RULES_ONLY
# Compile the Yara rules from a specified file on disk
if os.path.isfile(stuff):
rules = yara.compile(stuff)
else:
# Compile the Yara rules from a string passed on command line
# If the input starts with '{' or '/' then its a byte string or regex,
# in which case we don't use quotes to wrap it.
if stuff.startswith("{") or stuff.startswith("/"):
s = stuff
else:
s = '"' + stuff + '"'
rules = yara.compile(sources={
'namespace1' : 'rule z1 {strings: $a = ' + s + ' condition: $a}',
})
# We require YARA signatures for kernel mode
elif config.KERNEL:
debug.error("You must use YARA rules for kernel mode!")
addr_space = get_malware_space(config)
if config.KERNEL:
mods = list(modules.lsmod(addr_space))
procs = list(tasks.pslist(addr_space))
for mod in mods:
space = find_space(addr_space, procs, mod.DllBase)
if space != None:
data = space.zread(mod.DllBase, mod.SizeOfImage)
hits = rules.match(data=data)
if len(hits):
yield mod.BaseDllName, None, mod.DllBase, (mod.DllBase + mod.SizeOfImage), None, None, '-', hits, data
else:
if self._config.OFFSET != None:
procs = [self.virtual_process_from_physical_offset(addr_space, self._config.OFFSET)]
elif self._config.SCAN:
scan_procs = list(filescan.PSScan(self._config).calculate())
procs = []
for task in scan_procs:
procs.append(self.virtual_process_from_physical_offset(addr_space, task.obj_offset))
else:
procs = list(self.filter_tasks(tasks.pslist(addr_space)))
for proc in procs:
# get the DLLs so we know what to whitelist
if proc.Peb.Ldr.InLoadOrderModuleList:
dll_bases = [l.DllBase for l in proc.Peb.Ldr.InLoadOrderModuleList.list_of_type("_LDR_DATA_TABLE_ENTRY", "InLoadOrderLinks")]
else:
dll_bases = []
image_name = proc.ImageFileName
if self._config.OFFSET:
offset = proc.obj_offset
else:
offset = addr_space.vtop(proc.obj_offset)
for ps_ad, start, end, tag, prx, data in self.get_vads(proc):
# Ignore blocks of all zero
if data.count(chr(0)) == len(data):
continue
suspicious = False
hits = []