------=_Part_5447_16401853.1152673884138 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Microsoft Excel Could Allow Remote Code Execution by Malformed FNGROUPCOUNT value Vulnerability By OYXin( xin.ouyang at google mail ) of Nevis Labs http://www.nevisnetworks.com Vendor Microsoft Inc. Products affected: Microsoft Office 2000 Service Pack 3 Microsoft Office XP Service Pack 3 Microsoft Office 2003 Service Pack 1 or Service Pack 2 Microsoft Works Suites Microsoft Office X for Mac Microsoft Office 2004 for Mac Overview: A remote code execution vulnerability exists in Excel using a FNGROUPCOUNT value. An attacker could exploit the vulnerability by constructing a specially crafted Excel file that could allow remote code execution. Details: The vulnerable code is similar to MS06-012(CVE-2006-0031) which found by eyas. ============================================================================== eax=0e0e0e0e ebx=0000fff1 ecx=00002241 edx=0000000f esi=00138964 edi=0013ffff eip=30093040 esp=0013794c ebp=001388e4 iopl=0 nv up ei pl nz na po 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 Excel.EXE - Excel!Ordinal41+0x93040: 30093040 f3ab rep stosd es:0013ffff=74634100 Excel!Ordinal41+0x9302e: 3009302e 5c pop esp 3009302f f3ffff rep ??? 30093032 8bd9 mov ebx,ecx 30093034 c1e902 shr ecx,0x2 30093037 8d7c1520 lea edi,[ebp+edx+0x20] 3009303b b80e0e0e0e mov eax,0xe0e0e0e 30093040 f3ab rep stosd > 0:000> g > (b98.5fc): 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=0e0e0e0e edx=7c9037d8 esi=00000000 > edi=00000000 > eip=0e0e0e0e esp=0013757c ebp=0013759c iopl=0 nv up ei pl zr na > po nc > cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 > efl=00010246 > 0e0e0e0e ?? ??? ============================================================================== POC: No POC will be supplied Fix: Microsoft has released an update for Microsoft Office which isset to address this issue. This can be downloaded from: http://www.microsoft.com/technet/security/bulletin/MS06-037.mspx Vendor Response: 2006.04.12 Vendor notified via secure@microsoft.com 2006.04.12 Vendor responded 2006.07.11 Vendor released MS06-037 patch 2006.07.12 Advisory released Reference: 1. http://sc.openoffice.org/excelfileformat.pdf 2. http://www.microsoft.com/technet/security/bulletin/MS06-037.mspx 3. http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1308 4. http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0031 Greetings to Nevis lab guys and 0x557 guys :) ------=_Part_5447_16401853.1152673884138 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Microsoft Excel Could Allow Remote Code Execution by Malformed FNGROUPCOUNT value Vulnerability

By OYXin( xin.ouyang at google mail ) of Nevis Labs
http://www.nevisnetworks.com


Vendor
Microsoft Inc.

Products affected:
Microsoft Office 2000 Service Pack 3
Microsoft Office XP Service Pack 3
Microsoft Office 2003 Service Pack 1 or Service Pack 2
Microsoft Works Suites
Microsoft Office X for Mac
Microsoft Office 2004 for Mac


Overview:
A remote code execution vulnerability exists in Excel using a FNGROUPCOUNT value. An attacker could exploit the vulnerability by constructing a specially crafted Excel file that could allow remote code execution.


Details:
The vulnerable code is similar to MS06-012(CVE-2006-0031) which found by eyas.

==============================================================================
eax=0e0e0e0e ebx=0000fff1 ecx=00002241 edx=0000000f esi=00138964
edi=0013ffff
eip=30093040 esp=0013794c ebp=001388e4 iopl=0         nv up ei pl nz na
po 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 Excel.EXE -
Excel!Ordinal41+0x93040:
30093040 f3ab             rep     stosd                  
es:0013ffff=74634100

Excel!Ordinal41+0x9302e:
3009302e 5c               pop     esp
3009302f f3ffff           rep     ???
30093032 8bd9             mov     ebx,ecx
30093034 c1e902           shr     ecx,0x2
30093037 8d7c1520         lea     edi,[ebp+edx+0x20]
3009303b b80e0e0e0e       mov     eax,0xe0e0e0e
30093040 f3ab             rep     stosd

> 0:000> g
> (b98.5fc): 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=0e0e0e0e edx=7c9037d8 esi=00000000
> edi=00000000
> eip=0e0e0e0e esp=0013757c ebp=0013759c iopl=0         nv up ei pl zr na
> po nc
> cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             
> efl=00010246
> 0e0e0e0e ??               ???
==============================================================================

POC:
No POC will be supplied

Fix:
Microsoft has released an update for Microsoft Office which isset to address this issue. This can be downloaded from:
http://www.microsoft.com/technet/security/bulletin/MS06-037.mspx


Vendor Response:
2006.04.12 Vendor notified via secure@microsoft.com
2006.04.12 Vendor responded
2006.07.11 Vendor released MS06-037 patch
2006.07.12 Advisory released


Reference:
1. http://sc.openoffice.org/excelfileformat.pdf
2. http://www.microsoft.com/technet/security/bulletin/MS06-037.mspx
3. http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1308
4. http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0031


Greetings to Nevis lab guys and 0x557 guys :)

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