Author Archive

SpamAssassin 2010 bug

Posted by on Saturday, 2 January, 2010

From : https://secure.grepular.com/blog/index.php/2010/01/01/spamassassin-2010-bug/

I use SpamAssassin to filter the spam out of my incoming email. Last night I noticed that a legitimate email had a particularly high spam score. On further investigation I found that a rule named FH_DATE_PAST_20XX was triggering:

* 3.2 FH_DATE_PAST_20XX The date is grossly in the future

I checked the Date header of the email and it looked totally fine to me. It had just changed from the year 2009 to the year 2010. Could that be a coincidence? A quick look in /usr/share/spamassassin/72_active.cf turned up the rule:

header FH_DATE_PAST_20XX Date =~ /20[1-9][0-9]/ [if-unset: 2006]

Oops. That regex matches on any year between 2010 and 2099. I googled for the rule and came across this:

http://wiki.apache.org/spamassassin/Rules/FH_DATE_PAST_20XX

In the comments it mentioned the problem which I found: “Note: the current rule in 3.2 will start matching legitimate dates from 2010-01-01. See issue #5852.” Looking at issue 5852, the problem was first identified on 2008-Nov-05 and was “fixed” in CVS on 2009-Jun-30. I’m using the standard stable Debian package which doesn’t contain this fix yet so I had to stick the following in my local.cf file to apply a score of 0 to it:

score FH_DATE_PAST_20XX 0.0

I think a lot of systems will be experiencing false positives on their ham because of this at the moment. It is a particularly high scoring rule considering that the default threshold is 5.0.

As I understand it, rules aren’t distributed with SpamAssassin as of the next version (3.3) so hopefully problems like this wont happen in future. The “fix” which was supplied for this problem five months ago was to update the regex so it matches 2020-2099 instead.

You can read the thread I started about this issue on the SpamAssassin users list here. It’s the one started at “Fri, 01 Jan 2010 00:57:37 GMT” with the subject line “FH_DATE_PAST_20XX”


Kindle DRM Cracked

Posted by on Wednesday, 23 December, 2009

Looks like somebody had a little free time and decided to crack the kindle code. They have amusingly called the python code to do so ‘swindle’

On a side note, here is an excellent website pointed out to me who does what with your privacy on e-book readers http://www.eff.org/deeplinks/2009/12/e-book-privacy

You can find the original code here http://pastie.org/753699

In case it disappears, here it is

#! /usr/bin/python
 
# unswindle.pyw, version 5-rc1
 
# To run this program install a 32-bit version of Python 2.6 from
# <http://www.python.org/download/>.  Save this script file as unswindle.pyw.
# Find and save in the same directory a copy of mobidedrm.py.  Double-click on
# unswindle.pyw.  It will run Kindle For PC.  Open the book you want to
# decrypt.  Close Kindle For PC.  A dialog will open allowing you to select the
# output file.  And you're done!
 
# Revision history:
#   1 - Initial release
#   2 - Fixes to work properly on Windows versions >XP
#   3 - Fix minor bug in path extraction
#   4 - Fix error opening threads; detect Topaz books;
#       detect unsupported versions of K4PC
#   5 - Work on new (20091222) version of K4PC
 
"""
Decrypt Kindle For PC encrypted Mobipocket books.
"""
 
__license__ = 'GPL v3'
 
import sys
import os
import re
import tempfile
import shutil
import subprocess
import struct
import hashlib
import ctypes
from ctypes import *
from ctypes.wintypes import *
import binascii
import _winreg as winreg
import Tkinter
import Tkconstants
import tkMessageBox
import tkFileDialog
import traceback
 
#
# _extrawintypes.py
 
UBYTE = c_ubyte
ULONG_PTR = POINTER(ULONG)
PULONG = ULONG_PTR
PVOID = LPVOID
LPCTSTR = LPTSTR = c_wchar_p
LPBYTE = c_char_p
SIZE_T = c_uint
SIZE_T_p = POINTER(SIZE_T)
 
#
# _ntdll.py
 
NTSTATUS = DWORD
 
ntdll = windll.ntdll
 
class PROCESS_BASIC_INFORMATION(Structure):
_fields_ = [('Reserved1', PVOID),
('PebBaseAddress', PVOID),
('Reserved2', PVOID * 2),
('UniqueProcessId', ULONG_PTR),
('Reserved3', PVOID)]
 
# NTSTATUS WINAPI NtQueryInformationProcess(
#   __in       HANDLE ProcessHandle,
#   __in       PROCESSINFOCLASS ProcessInformationClass,
#   __out      PVOID ProcessInformation,
#   __in       ULONG ProcessInformationLength,
#   __out_opt  PULONG ReturnLength
# );
NtQueryInformationProcess = ntdll.NtQueryInformationProcess
NtQueryInformationProcess.argtypes = [HANDLE, DWORD, PVOID, ULONG, PULONG]
NtQueryInformationProcess.restype = NTSTATUS
 
#
# _kernel32.py
 
INFINITE = 0xffffffff
 
CREATE_UNICODE_ENVIRONMENT = 0x00000400
DEBUG_ONLY_THIS_PROCESS = 0x00000002
DEBUG_PROCESS = 0x00000001
 
THREAD_GET_CONTEXT = 0x0008
THREAD_QUERY_INFORMATION = 0x0040
THREAD_SET_CONTEXT = 0x0010
THREAD_SET_INFORMATION = 0x0020
 
EXCEPTION_BREAKPOINT = 0x80000003
EXCEPTION_SINGLE_STEP = 0x80000004
EXCEPTION_ACCESS_VIOLATION = 0xC0000005
 
DBG_CONTINUE = 0x00010002L
DBG_EXCEPTION_NOT_HANDLED = 0x80010001L
 
EXCEPTION_DEBUG_EVENT = 1
CREATE_THREAD_DEBUG_EVENT = 2
CREATE_PROCESS_DEBUG_EVENT = 3
EXIT_THREAD_DEBUG_EVENT = 4
EXIT_PROCESS_DEBUG_EVENT = 5
LOAD_DLL_DEBUG_EVENT = 6
UNLOAD_DLL_DEBUG_EVENT = 7
OUTPUT_DEBUG_STRING_EVENT = 8
RIP_EVENT = 9
 
class DataBlob(Structure):
_fields_ = [('cbData', c_uint),
('pbData', c_void_p)]
DataBlob_p = POINTER(DataBlob)
 
class SECURITY_ATTRIBUTES(Structure):
_fields_ = [('nLength', DWORD),
('lpSecurityDescriptor', LPVOID),
('bInheritHandle', BOOL)]
LPSECURITY_ATTRIBUTES = POINTER(SECURITY_ATTRIBUTES)
 
class STARTUPINFO(Structure):
_fields_ = [('cb', DWORD),
('lpReserved', LPTSTR),
('lpDesktop', LPTSTR),
('lpTitle', LPTSTR),
('dwX', DWORD),
('dwY', DWORD),
('dwXSize', DWORD),
('dwYSize', DWORD),
('dwXCountChars', DWORD),
('dwYCountChars', DWORD),
('dwFillAttribute', DWORD),
('dwFlags', DWORD),
('wShowWindow', WORD),
('cbReserved2', WORD),
('lpReserved2', LPBYTE),
('hStdInput', HANDLE),
('hStdOutput', HANDLE),
('hStdError', HANDLE)]
LPSTARTUPINFO = POINTER(STARTUPINFO)
 
class PROCESS_INFORMATION(Structure):
_fields_ = [('hProcess', HANDLE),
('hThread', HANDLE),
('dwProcessId', DWORD),
('dwThreadId', DWORD)]
LPPROCESS_INFORMATION = POINTER(PROCESS_INFORMATION)
 
EXCEPTION_MAXIMUM_PARAMETERS = 15
class EXCEPTION_RECORD(Structure):
pass
EXCEPTION_RECORD._fields_ = [
('ExceptionCode', DWORD),
('ExceptionFlags', DWORD),
('ExceptionRecord', POINTER(EXCEPTION_RECORD)),
('ExceptionAddress', LPVOID),
('NumberParameters', DWORD),
('ExceptionInformation', ULONG_PTR * EXCEPTION_MAXIMUM_PARAMETERS)]
 
class EXCEPTION_DEBUG_INFO(Structure):
_fields_ = [('ExceptionRecord', EXCEPTION_RECORD),
('dwFirstChance', DWORD)]
 
class CREATE_THREAD_DEBUG_INFO(Structure):
_fields_ = [('hThread', HANDLE),
('lpThreadLocalBase', LPVOID),
('lpStartAddress', LPVOID)]
 
class CREATE_PROCESS_DEBUG_INFO(Structure):
_fields_ = [('hFile', HANDLE),
('hProcess', HANDLE),
('hThread', HANDLE),
('dwDebugInfoFileOffset', DWORD),
('nDebugInfoSize', DWORD),
('lpThreadLocalBase', LPVOID),
('lpStartAddress', LPVOID),
('lpImageName', LPVOID),
('fUnicode', WORD)]
 
class EXIT_THREAD_DEBUG_INFO(Structure):
_fields_ = [('dwExitCode', DWORD)]
 
class EXIT_PROCESS_DEBUG_INFO(Structure):
_fields_ = [('dwExitCode', DWORD)]
 
class LOAD_DLL_DEBUG_INFO(Structure):
_fields_ = [('hFile', HANDLE),
('lpBaseOfDll', LPVOID),
('dwDebugInfoFileOffset', DWORD),
('nDebugInfoSize', DWORD),
('lpImageName', LPVOID),
('fUnicode', WORD)]
 
class UNLOAD_DLL_DEBUG_INFO(Structure):
_fields_ = [('lpBaseOfDll', LPVOID)]
 
class OUTPUT_DEBUG_STRING_INFO(Structure):
_fields_ = [('lpDebugStringData', LPSTR),
('fUnicode', WORD),
('nDebugStringLength', WORD)]
 
class RIP_INFO(Structure):
_fields_ = [('dwError', DWORD),
('dwType', DWORD)]
 
class _U(Union):
_fields_ = [('Exception', EXCEPTION_DEBUG_INFO),
('CreateThread', CREATE_THREAD_DEBUG_INFO),
('CreateProcessInfo', CREATE_PROCESS_DEBUG_INFO),
('ExitThread', EXIT_THREAD_DEBUG_INFO),
('ExitProcess', EXIT_PROCESS_DEBUG_INFO),
('LoadDll', LOAD_DLL_DEBUG_INFO),
('UnloadDll', UNLOAD_DLL_DEBUG_INFO),
('DebugString', OUTPUT_DEBUG_STRING_INFO),
('RipInfo', RIP_INFO)]
 
class DEBUG_EVENT(Structure):
_anonymous_ = ('u',)
_fields_ = [('dwDebugEventCode', DWORD),
('dwProcessId', DWORD),
('dwThreadId', DWORD),
('u', _U)]
LPDEBUG_EVENT = POINTER(DEBUG_EVENT)
 
CONTEXT_X86 = 0x00010000
CONTEXT_i386 = CONTEXT_X86
CONTEXT_i486 = CONTEXT_X86
 
CONTEXT_CONTROL = (CONTEXT_i386 | 0x0001) # SS:SP, CS:IP, FLAGS, BP
CONTEXT_INTEGER = (CONTEXT_i386 | 0x0002) # AX, BX, CX, DX, SI, DI
CONTEXT_SEGMENTS = (CONTEXT_i386 | 0x0004) # DS, ES, FS, GS
CONTEXT_FLOATING_POINT = (CONTEXT_i386 | 0x0008L) # 387 state
CONTEXT_DEBUG_REGISTERS =  (CONTEXT_i386 | 0x0010L) # DB 0-3,6,7
CONTEXT_EXTENDED_REGISTERS =  (CONTEXT_i386 | 0x0020L)
CONTEXT_FULL = (CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_SEGMENTS)
CONTEXT_ALL = (CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_SEGMENTS |
CONTEXT_FLOATING_POINT | CONTEXT_DEBUG_REGISTERS |
CONTEXT_EXTENDED_REGISTERS)
 
SIZE_OF_80387_REGISTERS = 80
class FLOATING_SAVE_AREA(Structure):
_fields_ = [('ControlWord', DWORD),
('StatusWord', DWORD),
('TagWord', DWORD),
('ErrorOffset', DWORD),
('ErrorSelector', DWORD),
('DataOffset', DWORD),
('DataSelector', DWORD),
('RegisterArea', BYTE * SIZE_OF_80387_REGISTERS),
('Cr0NpxState', DWORD)]
 
MAXIMUM_SUPPORTED_EXTENSION = 512
class CONTEXT(Structure):
_fields_ = [('ContextFlags', DWORD),
('Dr0', DWORD),
('Dr1', DWORD),
('Dr2', DWORD),
('Dr3', DWORD),
('Dr6', DWORD),
('Dr7', DWORD),
('FloatSave', FLOATING_SAVE_AREA),
('SegGs', DWORD),
('SegFs', DWORD),
('SegEs', DWORD),
('SegDs', DWORD),
('Edi', DWORD),
('Esi', DWORD),
('Ebx', DWORD),
('Edx', DWORD),
('Ecx', DWORD),
('Eax', DWORD),
('Ebp', DWORD),
('Eip', DWORD),
('SegCs', DWORD),
('EFlags', DWORD),
('Esp', DWORD),
('SegSs', DWORD),
('ExtendedRegisters', BYTE * MAXIMUM_SUPPORTED_EXTENSION)]
LPCONTEXT = POINTER(CONTEXT)
 
class LDT_ENTRY(Structure):
_fields_ = [('LimitLow', WORD),
('BaseLow',  WORD),
('BaseMid', UBYTE),
('Flags1', UBYTE),
('Flags2', UBYTE),
('BaseHi', UBYTE)]
LPLDT_ENTRY = POINTER(LDT_ENTRY)
 
kernel32 = windll.kernel32
 
# BOOL WINAPI CloseHandle(
#   __in  HANDLE hObject
# );
CloseHandle = kernel32.CloseHandle
CloseHandle.argtypes = [HANDLE]
CloseHandle.restype = BOOL
 
# BOOL WINAPI CreateProcess(
#   __in_opt     LPCTSTR lpApplicationName,
#   __inout_opt  LPTSTR lpCommandLine,
#   __in_opt     LPSECURITY_ATTRIBUTES lpProcessAttributes,
#   __in_opt     LPSECURITY_ATTRIBUTES lpThreadAttributes,
#   __in         BOOL bInheritHandles,
#   __in         DWORD dwCreationFlags,
#   __in_opt     LPVOID lpEnvironment,
#   __in_opt     LPCTSTR lpCurrentDirectory,
#   __in         LPSTARTUPINFO lpStartupInfo,
#   __out        LPPROCESS_INFORMATION lpProcessInformation
# );
CreateProcess = kernel32.CreateProcessW
CreateProcess.argtypes = [LPCTSTR, LPTSTR, LPSECURITY_ATTRIBUTES,
LPSECURITY_ATTRIBUTES, BOOL, DWORD, LPVOID, LPCTSTR,
LPSTARTUPINFO, LPPROCESS_INFORMATION]
CreateProcess.restype = BOOL
 
# HANDLE WINAPI OpenThread(
#   __in  DWORD dwDesiredAccess,
#   __in  BOOL bInheritHandle,
#   __in  DWORD dwThreadId
# );
OpenThread = kernel32.OpenThread
OpenThread.argtypes = [DWORD, BOOL, DWORD]
OpenThread.restype = HANDLE
 
# BOOL WINAPI ContinueDebugEvent(
#   __in  DWORD dwProcessId,
#   __in  DWORD dwThreadId,
#   __in  DWORD dwContinueStatus
# );
ContinueDebugEvent = kernel32.ContinueDebugEvent
ContinueDebugEvent.argtypes = [DWORD, DWORD, DWORD]
ContinueDebugEvent.restype = BOOL
 
# BOOL WINAPI DebugActiveProcess(
#   __in  DWORD dwProcessId
# );
DebugActiveProcess = kernel32.DebugActiveProcess
DebugActiveProcess.argtypes = [DWORD]
DebugActiveProcess.restype = BOOL
 
# BOOL WINAPI GetThreadContext(
#   __in     HANDLE hThread,
#   __inout  LPCONTEXT lpContext
# );
GetThreadContext = kernel32.GetThreadContext
GetThreadContext.argtypes = [HANDLE, LPCONTEXT]
GetThreadContext.restype = BOOL
 
# BOOL WINAPI GetThreadSelectorEntry(
#   __in   HANDLE hThread,
#   __in   DWORD dwSelector,
#   __out  LPLDT_ENTRY lpSelectorEntry
# );
GetThreadSelectorEntry = kernel32.GetThreadSelectorEntry
GetThreadSelectorEntry.argtypes = [HANDLE, DWORD, LPLDT_ENTRY]
GetThreadSelectorEntry.restype = BOOL
 
# BOOL WINAPI ReadProcessMemory(
#   __in   HANDLE hProcess,
#   __in   LPCVOID lpBaseAddress,
#   __out  LPVOID lpBuffer,
#   __in   SIZE_T nSize,
#   __out  SIZE_T *lpNumberOfBytesRead
# );
ReadProcessMemory = kernel32.ReadProcessMemory
ReadProcessMemory.argtypes = [HANDLE, LPCVOID, LPVOID, SIZE_T, SIZE_T_p]
ReadProcessMemory.restype = BOOL
 
# BOOL WINAPI SetThreadContext(
#   __in  HANDLE hThread,
#   __in  const CONTEXT *lpContext
# );
SetThreadContext = kernel32.SetThreadContext
SetThreadContext.argtypes = [HANDLE, LPCONTEXT]
SetThreadContext.restype = BOOL
 
# BOOL WINAPI WaitForDebugEvent(
#   __out  LPDEBUG_EVENT lpDebugEvent,
#   __in   DWORD dwMilliseconds
# );
WaitForDebugEvent = kernel32.WaitForDebugEvent
WaitForDebugEvent.argtypes = [LPDEBUG_EVENT, DWORD]
WaitForDebugEvent.restype = BOOL
 
# BOOL WINAPI WriteProcessMemory(
#   __in   HANDLE hProcess,
#   __in   LPVOID lpBaseAddress,
#   __in   LPCVOID lpBuffer,
#   __in   SIZE_T nSize,
#   __out  SIZE_T *lpNumberOfBytesWritten
# );
WriteProcessMemory = kernel32.WriteProcessMemory
WriteProcessMemory.argtypes = [HANDLE, LPVOID, LPCVOID, SIZE_T, SIZE_T_p]
WriteProcessMemory.restype = BOOL
 
# BOOL WINAPI FlushInstructionCache(
#   __in  HANDLE hProcess,
#   __in  LPCVOID lpBaseAddress,
#   __in  SIZE_T dwSize
# );
FlushInstructionCache = kernel32.FlushInstructionCache
FlushInstructionCache.argtypes = [HANDLE, LPCVOID, SIZE_T]
FlushInstructionCache.restype = BOOL
 
#
# debugger.py
 
FLAG_TRACE_BIT = 0x100
 
class DebuggerError(Exception):
pass
 
class Debugger(object):
def __init__(self, process_info):
self.process_info = process_info
self.pid = process_info.dwProcessId
self.tid = process_info.dwThreadId
self.hprocess = process_info.hProcess
self.hthread = process_info.hThread
self._threads = {self.tid: self.hthread}
self._processes = {self.pid: self.hprocess}
self._bps = {}
self._inactive = {}
 
def read_process_memory(self, addr, size=None, type=str):
if issubclass(type, basestring):
buf = ctypes.create_string_buffer(size)
ref = buf
else:
size = ctypes.sizeof(type)
buf = type()
ref = byref(buf)
copied = SIZE_T(0)
rv = ReadProcessMemory(self.hprocess, addr, ref, size, byref(copied))
if not rv:
addr = getattr(addr, 'value', addr)
raise DebuggerError("could not read memory @ 0x%08x" % (addr,))
if copied.value != size:
raise DebuggerError("insufficient memory read")
if issubclass(type, basestring):
return buf.raw
return buf
 
def set_bp(self, addr, callback, bytev=None):
hprocess = self.hprocess
if bytev is None:
byte = self.read_process_memory(addr, type=ctypes.c_byte)
bytev = byte.value
else:
byte = ctypes.c_byte(0)
self._bps[addr] = (bytev, callback)
byte.value = 0xcc
copied = SIZE_T(0)
rv = WriteProcessMemory(hprocess, addr, byref(byte), 1, byref(copied))
if not rv:
addr = getattr(addr, 'value', addr)
raise DebuggerError("could not write memory @ 0x%08x" % (addr,))
if copied.value != 1:
raise DebuggerError("insufficient memory written")
rv = FlushInstructionCache(hprocess, None, 0)
if not rv:
raise DebuggerError("could not flush instruction cache")
return
 
def _restore_bps(self):
for addr, (bytev, callback) in self._inactive.items():
self.set_bp(addr, callback, bytev=bytev)
self._inactive.clear()
 
def _handle_bp(self, addr):
hprocess = self.hprocess
hthread = self.hthread
bytev, callback = self._inactive[addr] = self._bps.pop(addr)
byte = ctypes.c_byte(bytev)
copied = SIZE_T(0)
rv = WriteProcessMemory(hprocess, addr, byref(byte), 1, byref(copied))
if not rv:
raise DebuggerError("could not write memory")
if copied.value != 1:
raise DebuggerError("insufficient memory written")
rv = FlushInstructionCache(hprocess, None, 0)
if not rv:
raise DebuggerError("could not flush instruction cache")
context = CONTEXT(ContextFlags=CONTEXT_FULL)
rv = GetThreadContext(hthread, byref(context))
if not rv:
raise DebuggerError("could not get thread context")
context.Eip = addr
callback(self, context)
context.EFlags |= FLAG_TRACE_BIT
rv = SetThreadContext(hthread, byref(context))
if not rv:
raise DebuggerError("could not set thread context")
return
 
def _get_peb_address(self):
hthread = self.hthread
hprocess = self.hprocess
try:
pbi = PROCESS_BASIC_INFORMATION()
rv = NtQueryInformationProcess(hprocess, 0, byref(pbi),
sizeof(pbi), None)
if rv != 0:
raise DebuggerError("could not query process information")
return pbi.PebBaseAddress
except DebuggerError:
pass
try:
context = CONTEXT(ContextFlags=CONTEXT_FULL)
rv = GetThreadContext(hthread, byref(context))
if not rv:
raise DebuggerError("could not get thread context")
entry = LDT_ENTRY()
rv = GetThreadSelectorEntry(hthread, context.SegFs, byref(entry))
if not rv:
raise DebuggerError("could not get selector entry")
low, mid, high = entry.BaseLow, entry.BaseMid, entry.BaseHi
fsbase = low | (mid << 16) | (high << 24)
pebaddr = self.read_process_memory(fsbase + 0x30, type=c_voidp)
return pebaddr.value
except DebuggerError:
pass
return 0x7ffdf000
 
def get_base_address(self):
addr = self._get_peb_address() + (2 * 4)
baseaddr = self.read_process_memory(addr, type=c_voidp)
return baseaddr.value
 
def main_loop(self):
event = DEBUG_EVENT()
finished = False
while not finished:
rv = WaitForDebugEvent(byref(event), INFINITE)
if not rv:
raise DebuggerError("could not get debug event")
self.pid = pid = event.dwProcessId
self.tid = tid = event.dwThreadId
self.hprocess = self._processes.get(pid, None)
self.hthread = self._threads.get(tid, None)
status = DBG_CONTINUE
evid = event.dwDebugEventCode
if evid == EXCEPTION_DEBUG_EVENT:
first = event.Exception.dwFirstChance
record = event.Exception.ExceptionRecord
exid = record.ExceptionCode
flags = record.ExceptionFlags
addr = record.ExceptionAddress
if exid == EXCEPTION_BREAKPOINT:
if addr in self._bps:
self._handle_bp(addr)
elif exid == EXCEPTION_SINGLE_STEP:
self._restore_bps()
else:
status = DBG_EXCEPTION_NOT_HANDLED
elif evid == LOAD_DLL_DEBUG_EVENT:
hfile = event.LoadDll.hFile
if hfile is not None:
rv = CloseHandle(hfile)
if not rv:
raise DebuggerError("error closing file handle")
elif evid == CREATE_THREAD_DEBUG_EVENT:
info = event.CreateThread
self.hthread = info.hThread
self._threads[tid] = self.hthread
elif evid == EXIT_THREAD_DEBUG_EVENT:
hthread = self._threads.pop(tid, None)
if hthread is not None:
rv = CloseHandle(hthread)
if not rv:
raise DebuggerError("error closing thread handle")
elif evid == CREATE_PROCESS_DEBUG_EVENT:
info = event.CreateProcessInfo
self.hprocess = info.hProcess
self._processes[pid] = self.hprocess
elif evid == EXIT_PROCESS_DEBUG_EVENT:
hprocess = self._processes.pop(pid, None)
if hprocess is not None:
rv = CloseHandle(hprocess)
if not rv:
raise DebuggerError("error closing process handle")
if pid == self.process_info.dwProcessId:
finished = True
rv = ContinueDebugEvent(pid, tid, status)
if not rv:
raise DebuggerError("could not continue debug")
return True
 
#
# unswindle.py
 
KINDLE_REG_KEY = \
r'Software\Classes\Amazon.KindleForPC.content\shell\open\command'
 
class UnswindleError(Exception):
pass
 
class PC1KeyGrabber(object):
HOOKS = {
'b9f7e422094b8c8966a0e881e6358116e03e5b7b': {
0x004a719d: '_no_debugger_here',
0x005a795b: '_no_debugger_here',
0x0054f7e0: '_get_pc1_pid',
0x004f9c79: '_get_book_path',
},
'd5124ee20dab10e44b41a039363f6143725a5417': {
0x0041150d: '_i_like_wine',
0x004a681d: '_no_debugger_here',
0x005a438b: '_no_debugger_here',
0x0054c9e0: '_get_pc1_pid',
0x004f8ac9: '_get_book_path',
},
}
 
@classmethod
def supported_version(cls, hexdigest):
return (hexdigest in cls.HOOKS)
 
def _taddr(self, addr):
return (addr - 0x00400000) + self.baseaddr
 
def __init__(self, debugger, hexdigest):
self.book_path = None
self.book_pid = None
self.baseaddr = debugger.get_base_address()
hooks = self.HOOKS[hexdigest]
for addr, mname in hooks.items():
debugger.set_bp(self._taddr(addr), getattr(self, mname))
 
def _i_like_wine(self, debugger, context):
context.Eax = 1
return
 
def _no_debugger_here(self, debugger, context):
context.Eip += 2
context.Eax = 0
return
 
def _get_book_path(self, debugger, context):
addr = debugger.read_process_memory(context.Esp, type=ctypes.c_voidp)
try:
path = debugger.read_process_memory(addr, 4096)
except DebuggerError:
pgrest = 0x1000 - (addr.value & 0xfff)
path = debugger.read_process_memory(addr, pgrest)
path = path.decode('utf-16', 'ignore')
if u'\0' in path:
path = path[:path.index(u'\0')]
if path[-4:].lower() not in ('.prc', '.pdb', '.mobi'):
return
self.book_path = path
 
def _get_pc1_pid(self, debugger, context):
addr = context.Esp + ctypes.sizeof(ctypes.c_voidp)
addr = debugger.read_process_memory(addr, type=ctypes.c_char_p)
pid = debugger.read_process_memory(addr, 8)
pid = self._checksum_pid(pid)
self.book_pid = pid
 
def _checksum_pid(self, s):
letters = "ABCDEFGHIJKLMNPQRSTUVWXYZ123456789"
crc = (~binascii.crc32(s,-1))&0xFFFFFFFF
crc = crc ^ (crc >> 16)
res = s
l = len(letters)
for i in (0,1):
b = crc & 0xff
pos = (b // l) ^ (b % l)
res += letters[pos%l]
crc >>= 8
return res
 
class Unswindler(object):
def __init__(self):
self._exepath = self._get_exe_path()
self._hexdigest = self._get_hexdigest()
self._exedir = os.path.dirname(self._exepath)
self._mobidedrmpath = self._get_mobidedrm_path()
 
def _get_mobidedrm_path(self):
basedir = sys.modules[self.__module__].__file__
basedir = os.path.dirname(basedir)
for basename in ('mobidedrm', 'mobidedrm.py', 'mobidedrm.pyw'):
path = os.path.join(basedir, basename)
if os.path.isfile(path):
return path
raise UnswindleError("could not locate MobiDeDRM script")
 
def _get_exe_path(self):
path = None
for root in (winreg.HKEY_CURRENT_USER, winreg.HKEY_LOCAL_MACHINE):
try:
regkey = winreg.OpenKey(root, KINDLE_REG_KEY)
path = winreg.QueryValue(regkey, None)
break
except WindowsError:
pass
else:
raise UnswindleError("Kindle For PC installation not found")
if '"' in path:
path = re.search(r'"(.*?)"', path).group(1)
return path
 
def _get_hexdigest(self):
path = self._exepath
sha1 = hashlib.sha1()
with open(path, 'rb') as f:
data = f.read(4096)
while data:
sha1.update(data)
data = f.read(4096)
hexdigest = sha1.hexdigest()
if not PC1KeyGrabber.supported_version(hexdigest):
raise UnswindleError("Unsupported version of Kindle For PC")
return hexdigest
 
def _is_topaz(self, path):
with open(path, 'rb') as f:
magic = f.read(4)
if magic == 'TPZ0':
return True
return False
 
def get_book(self):
creation_flags = (CREATE_UNICODE_ENVIRONMENT |
DEBUG_PROCESS |
DEBUG_ONLY_THIS_PROCESS)
startup_info = STARTUPINFO()
process_info = PROCESS_INFORMATION()
path = pid = None
try:
rv = CreateProcess(self._exepath, None, None, None, False,
creation_flags, None, self._exedir,
byref(startup_info), byref(process_info))
if not rv:
raise UnswindleError("failed to launch Kindle For PC")
debugger = Debugger(process_info)
grabber = PC1KeyGrabber(debugger, self._hexdigest)
debugger.main_loop()
path = grabber.book_path
pid = grabber.book_pid
finally:
if process_info.hThread is not None:
CloseHandle(process_info.hThread)
if process_info.hProcess is not None:
CloseHandle(process_info.hProcess)
if path is None:
raise UnswindleError("failed to determine book path")
if self._is_topaz(path):
raise UnswindleError("cannot decrypt Topaz format book")
if pid is None:
raise UnswindleError("failed to determine book PID")
return (path, pid)
 
def decrypt_book(self, inpath, outpath, pid):
# darkreverser didn't protect mobidedrm's script execution to allow
# importing, so we have to just run it in a subprocess
with tempfile.NamedTemporaryFile(delete=False) as tmpf:
tmppath = tmpf.name
args = [sys.executable, self._mobidedrmpath, inpath, tmppath, pid]
mobidedrm = subprocess.Popen(args, stderr=subprocess.STDOUT,
stdout=subprocess.PIPE,
universal_newlines=True)
output = mobidedrm.communicate()[0]
if not output.endswith("done\n"):
try:
os.remove(tmppath)
except OSError:
pass
raise UnswindleError("problem running MobiDeDRM:\n" + output)
shutil.move(tmppath, outpath)
return
 
class ExceptionDialog(Tkinter.Frame):
def __init__(self, root, text):
Tkinter.Frame.__init__(self, root, border=5)
label = Tkinter.Label(self, text="Unexpected error:",
anchor=Tkconstants.W, justify=Tkconstants.LEFT)
label.pack(fill=Tkconstants.X, expand=0)
self.text = Tkinter.Text(self)
self.text.pack(fill=Tkconstants.BOTH, expand=1)
self.text.insert(Tkconstants.END, text)
 
def gui_main(argv=sys.argv):
root = Tkinter.Tk()
root.withdraw()
progname = os.path.basename(argv[0])
try:
unswindler = Unswindler()
inpath, pid = unswindler.get_book()
outpath = tkFileDialog.asksaveasfilename(
parent=None, title='Select unencrypted Mobipocket file to produce',
defaultextension='.mobi', filetypes=[('MOBI files', '.mobi'),
('All files', '.*')])
if not outpath:
return 0
unswindler.decrypt_book(inpath, outpath, pid)
except UnswindleError, e:
tkMessageBox.showerror("Unswindle For PC", "Error: " + str(e))
return 1
except Exception:
root.wm_state('normal')
root.title('Unswindle For PC')
text = traceback.format_exc()
ExceptionDialog(root, text).pack(fill=Tkconstants.BOTH, expand=1)
root.mainloop()
return 1
 
def cli_main(argv=sys.argv):
progname = os.path.basename(argv[0])
args = argv[1:]
if len(args) != 1:
sys.stderr.write("usage: %s OUTFILE\n" % (progname,))
return 1
outpath = args[0]
unswindler = Unswindler()
inpath, pid = unswindler.get_book()
unswindler.decrypt_book(inpath, outpath, pid)
return 0
 
if __name__ == '__main__':
sys.exit(gui_main())

Apache modules to help your server

Posted by on Friday, 27 November, 2009

libapache2-mod-bw – bandwidth limiting module

This module allows you to limit bandwidth usage on every virtual host or directory or to restrict the number of simultaneous connections.

The bandwidth control, for example, can be configured according to the criteria: origin of the connection, file extension, file size or user agent of the client.
Example:

LoadModule bw_module /usr/lib/apache2/modules/mod_bw.so
BandWidthModule On
BandWidth all 40000
MinBandWidth all 10000
ForceBandWidthModule On

libapache2-mod-defensible – module for Apache2 which provides DNSBL usage

mod_defensible implements usage of DNSBL servers to block access to a Web site or to specific locations.

Example:

DnsblUse On
DnsblServers httpbl.abuse.ch sbl-xbl.spamhaus.org
DnsblNameserver 145.253.2.75

libapache2-mod-evasive – evasive module to minimize HTTP DoS or brute force attacks

mod_evasive is an evasive maneuvers module for Apache to provide some protection in the event of an HTTP DoS or DDoS attack or brute force attack.

It is also designed to be a detection tool, and can be easily configured to talk to ipchains, firewalls, routers, and etcetera.

Example:

<IfModule mod_evasive20.c>
DOSHashTableSize 3097
DOSPageCount 5
DOSSiteCount 100
DOSPageInterval 1
DOSSiteInterval 1
DOSBlockingPeriod 600
</IfModule>

Comes with a perl script to test it also.

vps:/etc/apache2/mods-available# perl /usr/share/doc/libapache2-mod-evasive/examples/test.pl
HTTP/1.1 200 OK
HTTP/1.1 200 OK
HTTP/1.1 200 OK
HTTP/1.1 200 OK
HTTP/1.1 200 OK
HTTP/1.1 200 OK
HTTP/1.1 403 Forbidden
HTTP/1.1 403 Forbidden
HTTP/1.1 403 Forbidden
HTTP/1.1 403 Forbidden

libapache2-mod-line-edit – search-and-replace line editor module for apache 2

mod_line_edit is a general-purpose apache 2 filter for text documents. It operates as a simple on-the-fly line editor, applying search-and-replace rules defined in a configuration or .htaccess file. Both simple text and regular expression search and replace are supported.

Example:

SetOutputFilter line-editor
SetEnv LineEdit “text/plain;text/css;text/html”
LELineEnd ANY
LERewriteRule https?://(www\.)?example\.com http://example-development.yoursite.co.nz Ri

Throw something like that into your or somewhere and you instantly fixed all those problem URLS on your development system, without touching the source files at all.
This is ideal to stop/prevent people exploiting various holes in web applications and inserting javascript redirects etc.

Please note: the name of all these modules is debian/ubuntu related. Centos or RedHat based distros may have another name for the same modules. If you need any of these installed just drop an email into the support box and let us know.