Date: Sun, 3 Jun 2007 01:48:03 +0800
From: xWinGs <xwings@...urity.net.my>
To: submit@...w0rm.com, full-disclosure@...ts.grok.org.uk
Subject: SNMY200706_01 : GBD UPX File Handling Buffer
	Overflow Vulnerability

Title : GBD UPX File Handling Buffer Overflow Vulnerability

security.net.my Advisory: SNMY200706_01
Release Date            : 2007-06-02
Last Update             : 2007-06-02
Critical                : Low
Impact                  : System access
Where                   : From Local
Solution Status         : None
Software                : GDB 6.6 and above
CVE reference           : None
Related Files           : http://blog.xwings.net/?p=71

****************************************************
** Description :
****************************************************

A vulnerability has been reported in GDB, which possible exploited by 
malicious people
to compromise a vulnerable system.

The vulnerability is caused due to a boundary error in "coffread.c" when 
unpacking
executable files compressed with UPX. This can be exploited to cause a buffer 
overflow
and potentially allows arbitrary code execution via a specially-crafted UPX 
packed file.

The vulnerability has been reported in versions 6.6 till the lastest CVS.


****************************************************
** Provided and/or discovered by :
****************************************************

Discovered by KaiJern, Lau. (xwings<at>security<dot>net<dot>my)

****************************************************
** Changelog:
****************************************************

2006-01-13: Updated advisory with information from 3Com's Zero Day Initiative.
2006-01-17: Added link to US-CERT vulnerability note.

****************************************************
** Crashing GDB :
****************************************************

$ file gdbupx
gdbupx: MS-DOS executable PE  for MS Windows (console) Intel 80386 32-bit, UPX 
compressed

$ upx -d gdbupx
Ultimate Packer for eXecutables
Copyright (C) 1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006
UPX 2.02        Markus Oberhumer, Laszlo Molnar & John Reiser   Aug 13th 2006
File size         Ratio      Format      Name
--------------------   ------   -----------   -----------
upx: gdbupx: CantUnpackException: exe header corrupte.e
Unpacked 0 files.

$ gdb -v
GNU gdb 6.6
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-linux-gnu".

$ gdb gdbtest/bin/gdb
GNU gdb 6.6
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-linux-gnu"...
Using host libthread_db library "/lib/libthread_db.so.1".
Really redefine built-in command "frame"? (y or n) [answered Y; input not from 
terminal]
Really redefine built-in command "thread"? (y or n) [answered Y; input not 
from terminal]
Really redefine built-in command "start"? (y or n) [answered Y; input not from 
terminal]

gdb>r gdbupx
GNU gdb 6.6.50.20070531-cvs
Copyright (C) 2007 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-linux-gnu"...

Program received signal SIGSEGV, Segmentation fault.
_______________________________________________________________________________
eax:08334F70 ebx:00000000  ecx:08337168  edx:082C3240     eflags:00210246
esi:0833D320 edi:0833D34C  esp:BF8E54D0  ebp:BF8E54F8     eip:0814CD82
cs:0073  ds:007B  es:007B  fs:0000  gs:0033  ss:007B    o d I t s Z a P c
[007B:BF8E54D0]---------------------------------------------------------[stack]
BF8E5500 : 80 02 00 00  00 00 00 00 - FC 01 00 00  00 00 00 
00 ................
BF8E54F0 : 30 00 00 00  F0 55 8E BF - 38 56 8E BF  50 D7 14 08 
0....U..8V..P...
BF8E54E0 : 68 71 33 08  F4 BD 2E 08 - F0 55 8E BF  00 00 00 00 
hq3......U......
BF8E54D0 : 31 2D 25 08  FF FF FF FF - F8 54 8E BF  7D C0 14 08 
1-%......T..}...
[007B:0833D320]---------------------------------------------------------[ 
data]
0833D320 : 00 00 00 00  00 00 00 00 - 00 00 00 00  00 00 00 
00 ................
0833D330 : 00 00 00 00  00 00 00 00 - 00 00 00 00  00 00 00 
00 ................
[0073:0814CD82]---------------------------------------------------------[ 
code]
0x814cd82 <process_coff_symbol+130>:    movzx  eax,BYTE PTR [ebx]
0x814cd85 <process_coff_symbol+133>:    cmp    al,BYTE PTR [edx+24]
0x814cd88 <process_coff_symbol+136>:    mov    BYTE PTR [esi+12],0x1
0x814cd8c <process_coff_symbol+140>:    mov    DWORD PTR [esp+12],ecx
0x814cd90 <process_coff_symbol+144>:    sete   al
0x814cd93 <process_coff_symbol+147>:    movzx  eax,al
------------------------------------------------------------------------------
0x0814cd82 in process_coff_symbol (cs=0xbf8e55f0, aux=0x82ebdf4, 
objfile=0x8337168) at coffread.c:1482
1482      name = EXTERNAL_NAME (name, objfile->obfd);
gdb>bt
#0  0x0814cd82 in process_coff_symbol (cs=0xbf8e55f0, aux=0x82ebdf4, 
objfile=0x8337168) at coffread.c:1482
#1  0x0814d750 in coff_symfile_read (objfile=0x8337168, mainline=0x1) at 
coffread.c:1084
#2  0x08108ff3 in syms_from_objfile (objfile=0x8337168, addrs=0x833e280,
offsets=0x0, num_offsets=0x0, mainline=0x1, verbo=0x0) at symfile.c:876
#3  0x081093de in symbol_file_add_with_addrs_or_offsets (abfd=0x8334f70,
from_tty=0x0, addrs=0x0, offsets=0x0, num_offsets=0x0, mainline=0x1, 
flags=0x0) at symfile.c:988
#4  0x0810a265 in symbol_file_add_main_1 (args=0x8334f70 "\001", 
from_tty=0x82c3240,
flags=<value optimized out>) at symfile.c:1121
#5  0x08121b92 in catch_command_errors (command=0x810a3f0 
<symbol_file_add_main>,
arg=0xbf8e72ad "../../gdbupx", from_tty=0x0, mask=0x6) at exceptions.c:530
#6  0x0807eb38 in captured_main (data=0xbf8e58f4) at .././gdb/main.c:728
#7  0x08121c2b in catch_errors (func=0x807e1e0 <captured_main>, 
func_args=0xbf8e58f4,
errstring=0x8252d31 "", mask=0x6) at exceptions.c:515
#8  0x0807e193 in gdb_main (args=0xbf8e58f4) at .././gdb/main.c:881
#9  0x0807e155 in main (argc=0x0, argv=0x8332df0) at gdb.c:35

****************************************************
** Thanks To :
****************************************************

        i.   BSDaemon @ kernelhacking.com
        ii.  RedDragon @ thc
        iii. Committee Members of hackinthebox.org
        iv.  pulltheplug.org

-- 
--

Regards,
xWinGs aka KJ, Lau

==

All good things ...
come by grace, and grace come by art, and art does not come easy.

** From : xwings (at) security (dot) net (dot) my

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