Microsoft Excel 2003 11.8335.8333 – Use-After-Free
####################################################################### Luigi Auriemma Application: Microsoft Excel http://office.microsoft.com/en-us/excel/ http://office.microsoft.com/en-us/downloads/CD001022531.aspx Versions: tested Office 2003 11.8335.8333 SP3 Platforms: Windows Bug: use after free Exploitation: file Date: 03 Nov 2011 (found 24 Aug 2011) Author: Luigi Auriemma e-mail: aluigi@autistici.org web: aluigi.org ####################################################################### 1) Introduction 2) Bug 3) The Code 4) Fix ####################################################################### =============== 1) Introduction =============== Excel 2003 is a spreadsheet program, part of the Office 2003 suite still supported by Microsoft. ####################################################################### ====== 2) Bug ====== Use-after-free probably located in the code that handles the vbscript macros: eax=00492d78 ebx=00000000 ecx=feeefeee edx=00185ff8 esi=004c72b8 edi=00492478 eip=65058591 esp=00185fd0 ebp=0018601c iopl=0 nv up ei pl nz na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00210206 VBE6!DllVbeInit+0x40f6f: 65058591 ff11 call dword ptr [ecx] ds:002b:feeefeee=???????? 0:000:x86> k ChildEBP RetAddr 0018601c 6501c0dd VBE6!DllVbeInit+0x40f6f 00186074 6505dee2 VBE6!DllVbeInit+0x4abb 001860a8 6505e21c VBE6!DllVbeInit+0x468c0 00186220 767cbc9c VBE6!DllVbeInit+0x46bfa 00000000 00000000 ole32!StgIsStorageFile+0x764 How to replicate: - open the proof-of-concept via web or manually - "An error occurred while loading 'Module1'. Do you want to continue loading the project?" select No, if you select Yes then the bug doesn't seem to be replicable - "Unexpected error (32790)" select OK - "Excel found unreadable content in ..." Yes or No is the same - now reopen the proof-of-concept and the bug will happen immediately The reopening of the same file seems necessary probably because the Office suite uses only one instance of its programs and performs a particular reallocation of the resources when a file gets reopened. Note that I have tested only the latest version of Office 2003 on Windows 7. The proof-of-concept is NOT optimized. Modified bytes: excel_1a.xls: 0006FCA4 AA 01 excel_1b.xls: 0006FCB0 AD 40 ####################################################################### =========== 3) The Code =========== http://aluigi.org/poc/excel_1.zip https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/18078.zip ####################################################################### ====== 4) Fix ====== No fix. ####################################################################### |